review.tizen.org Git - platform/kernel/linux-starfive.git/log

Merge tag 'btree-complain-bad-records-6.4_2023-04-11' of git://git./linux/kernel/git/djwong/xfs-linux into guilt/xfs-for-next

xfs: standardize btree record checking code [v24.5]

While I was cleaning things up for 6.1, I noticed that the btree
_query_range and _query_all functions don't perform the same checking
that the _get_rec functions perform. In fact, they don't perform /any/
sanity checking, which means that callers aren't warned about impossible
records.

Therefore, hoist the record validation and complaint logging code into
separate functions, and call them from any place where we convert an
ondisk record into an incore record. For online scrub, we can replace
checking code with a call to the record checking functions in libxfs,
thereby reducing the size of the codebase.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Merge tag 'scrub-drain-intents-6.4_2023-04-11' of git://git./linux/kernel/git/djwong/xfs-linux into guilt/xfs-for-next

xfs: drain deferred work items when scrubbing [v24.5]

The design doc for XFS online fsck contains a long discussion of the
eventual consistency models in use for XFS metadata.  In that chapter,
we note that it is possible for scrub to collide with a chain of
deferred space metadata updates, and proposes a lightweight solution:
The use of a pending-intents counter so that scrub can wait for the
system to drain all chains.

This patchset implements that scrub drain.  The first patch implements
the basic mechanism, and the subsequent patches reduce the runtime
overhead by converting the implementation to use sloppy counters and
introducing jump labels to avoid walking into scrub hooks when it isn't
running.  This last paradigm repeats elsewhere in this megaseries.

v23.1: make intent items take an active ref to the perag structure and
       document why we bump and drop the intent counts when we do

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Merge tag 'scrub-fix-legalese-6.4_2023-04-11' of git://git./linux/kernel/git/djwong/xfs-linux into guilt/xfs-for-next

xfs_scrub: fix licensing and copyright notices [v24.5]

Fix various attribution problems in the xfs_scrub source code, such as
the author's contact information, out of date SPDX tags, and a rough
estimate of when the feature was under heavy development. The most
egregious parts are the files that are missing license information
completely.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Merge tag 'pass-perag-refs-6.4_2023-04-11' of git://git./linux/kernel/git/djwong/xfs-linux into guilt/xfs-for-next

xfs: pass perag references around when possible [v24.5]

Avoid the cost of perag radix tree lookups by passing around active perag
references when possible.

v24.2: rework some of the naming and whatnot so there's less opencoding

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Merge tag 'intents-perag-refs-6.4_2023-04-11' of git://git./linux/kernel/git/djwong/xfs-linux into guilt/xfs-for-next

xfs: make intent items take a perag reference [v24.5]

Now that we've cleaned up some code warts in the deferred work item
processing code, let's make intent items take an active perag reference
from their creation until they are finally freed by the defer ops
machinery. This change facilitates the scrub drain in the next patchset
and will make it easier for the future AG removal code to detect a busy
AG in need of quiescing.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

Merge tag 'online-fsck-design-6.4_2023-04-11' of git://git./linux/kernel/git/djwong/xfs-linux into guilt/xfs-for-next

xfs: design documentation for online fsck [v24.5]

After six years of development and a nearly two year hiatus from
patchbombing, I think it is time to resume the process of merging the
online fsck feature into XFS.  The full patchset comprises 105 separate
patchsets that capture 470 patches across the kernel, xfsprogs, and
fstests projects.

I would like to merge this feature into upstream in time for the 2023
LTS kernel.  As of 5.15 (aka last year's LTS), we have merged all
generally useful infrastructure improvements into the regular
filesystem.  The only changes to the core filesystem that remain are the
ones that are only useful to online fsck itself.  In other words, the
vast majority of the new code in the patchsets comprising the online
fsck feature are is mostly self contained and can be turned off via
Kconfig.

Many of you readers might be wondering -- why have I chosen to make one
large submission with 100+ patchsets comprising ~500 patches?  Why
didn't I merge small pieces of functionality bit by bit and revise
common code as necessary?  Well, the simple answer is that in the past
six years, the fundamental algorithms have been revised repeatedly as
I've built out the functionality.  In other words, the codebase as it is
now has the benefit that I now know every piece that's necessary to get
the job done in a reasonable manner and within the constraints laid out
by community reviews.  I believe this has reduced code churn in mainline
and freed up my time so that I can iterate faster.

As a concession to the mail servers, I'm breaking up the submission into
smaller pieces; I'm only pushing the design document and the revisions
to the existing scrub code, which is the first 20%% of the patches.
Also, I'm arbitrarily restarting the version numbering by reversioning
all patchsets from version 22 to epoch 23, version 1.

The big question to everyone reading this is: How might I convince you
that there is more merit in merging the whole feature and dealing with
the consequences than continuing to maintain it out of tree?

---------

To prepare the XFS community and potential patch reviewers for the
upstream submission of the online fsck feature, I decided to write a
document capturing the broader picture behind the online repair
development effort.  The document begins by defining the problems that
online fsck aims to solve and outlining specific use cases for the
functionality.

Using that as a base, the rest of the design document presents the high
level algorithms that fulfill the goals set out at the start and the
interactions between the large pieces of the system.  Case studies round
out the design documentation by adding the details of exactly how
specific parts of the online fsck code integrate the algorithms with the
filesystem.

The goal of this effort is to help the XFS community understand how the
gigantic online repair patchset works.  The questions I submit to the
community reviewers are:

1. As you read the design doc (and later the code), do you feel that you
   understand what's going on well enough to try to fix a bug if you
   found one?

2. What sorts of interactions between systems (or between scrub and the
   rest of the kernel) am I missing?

3. Do you feel confident enough in the implementation as it is now that
   the benefits of merging the feature (as EXPERIMENTAL) outweigh any
   potential disruptions to XFS at large?

4. Are there problematic interactions between subsystems that ought to
   be cleared up before merging?

5. Can I just merge all of this?

I intend to commit this document to the kernel's documentation directory
when we start merging the patchset, albeit without the links to
git.kernel.org.  A much more readable version of this is posted at:
https://djwong.org/docs/xfs-online-fsck-design/

v2: add missing sections about: all the in-kernel data structures and
    new apis that the scrub and repair functions use; how xattrs and
    directories are checked; how space btree records are checked; and
    add more details to the parts where all these bits tie together.
    Proofread for verb tense inconsistencies and eliminate vague 'we'
    usage.  Move all the discussion of what we can do with pageable
    kernel memory into a single source file and section.  Document where
    log incompat feature locks fit into the locking model.

v3: resync with 6.0, fix a few typos, begin discussion of the merging
    plan for this megapatchset.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: fix BUG_ON in xfs_getbmap()

There's issue as follows:
XFS: Assertion failed: (bmv->bmv_iflags & BMV_IF_DELALLOC) != 0, file: fs/xfs/xfs_bmap_util.c, line: 329
------------[ cut here ]------------
kernel BUG at fs/xfs/xfs_message.c:102!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 14612 Comm: xfs_io Not tainted 6.3.0-rc2-next-20230315-00006-g2729d23ddb3b-dirty #422
RIP: 0010:assfail+0x96/0xa0
RSP: 0018:ffffc9000fa178c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff888179a18000
RDX: 0000000000000000 RSI: ffff888179a18000 RDI: 0000000000000002
RBP: 0000000000000000 R08: ffffffff8321aab6 R09: 0000000000000000
R10: 0000000000000001 R11: ffffed1105f85139 R12: ffffffff8aacc4c0
R13: 0000000000000149 R14: ffff888269f58000 R15: 000000000000000c
FS:  00007f42f27a4740(0000) GS:ffff88882fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000b92388 CR3: 000000024f006000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
xfs_getbmap+0x1a5b/0x1e40
xfs_ioc_getbmap+0x1fd/0x5b0
xfs_file_ioctl+0x2cb/0x1d50
__x64_sys_ioctl+0x197/0x210
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Above issue may happen as follows:
         ThreadA                       ThreadB
do_shared_fault
__do_fault
  xfs_filemap_fault
   __xfs_filemap_fault
    filemap_fault
                             xfs_ioc_getbmap -> Without BMV_IF_DELALLOC flag
      xfs_getbmap
       xfs_ilock(ip, XFS_IOLOCK_SHARED);
       filemap_write_and_wait
do_page_mkwrite
  xfs_filemap_page_mkwrite
   __xfs_filemap_fault
    xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
    iomap_page_mkwrite
     ...
     xfs_buffered_write_iomap_begin
      xfs_bmapi_reserve_delalloc -> Allocate delay extent
                              xfs_ilock_data_map_shared(ip)
                      xfs_getbmap_report_one
       ASSERT((bmv->bmv_iflags & BMV_IF_DELALLOC) != 0)
                        -> trigger BUG_ON

As xfs_filemap_page_mkwrite() only hold XFS_MMAPLOCK_SHARED lock, there's
small window mkwrite can produce delay extent after file write in xfs_getbmap().
To solve above issue, just skip delalloc extents.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: verify buffer contents when we skip log replay

syzbot detected a crash during log recovery:

XFS (loop0): Mounting V5 Filesystem bfdc47fc-10d8-4eed-a562-11a831b3f791
XFS (loop0): Torn write (CRC failure) detected at log block 0x180. Truncating head block from 0x200.
XFS (loop0): Starting recovery (logdev: internal)
==================================================================
BUG: KASAN: slab-out-of-bounds in xfs_btree_lookup_get_block+0x15c/0x6d0 fs/xfs/libxfs/xfs_btree.c:1813
Read of size 8 at addr ffff88807e89f258 by task syz-executor132/5074

CPU: 0 PID: 5074 Comm: syz-executor132 Not tainted 6.2.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
print_address_description+0x74/0x340 mm/kasan/report.c:306
print_report+0x107/0x1f0 mm/kasan/report.c:417
kasan_report+0xcd/0x100 mm/kasan/report.c:517
xfs_btree_lookup_get_block+0x15c/0x6d0 fs/xfs/libxfs/xfs_btree.c:1813
xfs_btree_lookup+0x346/0x12c0 fs/xfs/libxfs/xfs_btree.c:1913
xfs_btree_simple_query_range+0xde/0x6a0 fs/xfs/libxfs/xfs_btree.c:4713
xfs_btree_query_range+0x2db/0x380 fs/xfs/libxfs/xfs_btree.c:4953
xfs_refcount_recover_cow_leftovers+0x2d1/0xa60 fs/xfs/libxfs/xfs_refcount.c:1946
xfs_reflink_recover_cow+0xab/0x1b0 fs/xfs/xfs_reflink.c:930
xlog_recover_finish+0x824/0x920 fs/xfs/xfs_log_recover.c:3493
xfs_log_mount_finish+0x1ec/0x3d0 fs/xfs/xfs_log.c:829
xfs_mountfs+0x146a/0x1ef0 fs/xfs/xfs_mount.c:933
xfs_fs_fill_super+0xf95/0x11f0 fs/xfs/xfs_super.c:1666
get_tree_bdev+0x400/0x620 fs/super.c:1282
vfs_get_tree+0x88/0x270 fs/super.c:1489
do_new_mount+0x289/0xad0 fs/namespace.c:3145
do_mount fs/namespace.c:3488 [inline]
__do_sys_mount fs/namespace.c:3697 [inline]
__se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3674
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f89fa3f4aca
Code: 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffd5fb5ef8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00646975756f6e2c RCX: 00007f89fa3f4aca
RDX: 0000000020000100 RSI: 0000000020009640 RDI: 00007fffd5fb5f10
RBP: 00007fffd5fb5f10 R08: 00007fffd5fb5f50 R09: 000000000000970d
R10: 0000000000200800 R11: 0000000000000206 R12: 0000000000000004
R13: 0000555556c6b2c0 R14: 0000000000200800 R15: 00007fffd5fb5f50
</TASK>

The fuzzed image contains an AGF with an obviously garbage
agf_refcount_level value of 32, and a dirty log with a buffer log item
for that AGF.  The ondisk AGF has a higher LSN than the recovered log
item.  xlog_recover_buf_commit_pass2 reads the buffer, compares the
LSNs, and decides to skip replay because the ondisk buffer appears to be
newer.

Unfortunately, the ondisk buffer is corrupt, but recovery just read the
buffer with no buffer ops specified:

error = xfs_buf_read(mp->m_ddev_targp, buf_f->blf_blkno,
buf_f->blf_len, buf_flags, &bp, NULL);

Skipping the buffer leaves its contents in memory unverified.  This sets
us up for a kernel crash because xfs_refcount_recover_cow_leftovers
reads the buffer (which is still around in XBF_DONE state, so no read
verification) and creates a refcountbt cursor of height 32.  This is
impossible so we run off the end of the cursor object and crash.

Fix this by invoking the verifier on all skipped buffers and aborting
log recovery if the ondisk buffer is corrupt.  It might be smarter to
force replay the log item atop the buffer and then see if it'll pass the
write verifier (like ext4 does) but for now let's go with the
conservative option where we stop immediately.

Link: https://syzkaller.appspot.com/bug?extid=7e9494b8b399902e994e
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: _{attr,data}_map_shared should take ILOCK_EXCL until iread_extents is completely done

While fuzzing the data fork extent count on a btree-format directory
with xfs/375, I observed the following (excerpted) splat:

XFS: Assertion failed: xfs_isilocked(ip, XFS_ILOCK_EXCL), file: fs/xfs/libxfs/xfs_bmap.c, line: 1208
------------[ cut here ]------------
WARNING: CPU: 0 PID: 43192 at fs/xfs/xfs_message.c:104 assfail+0x46/0x4a [xfs]
Call Trace:
<TASK>
xfs_iread_extents+0x1af/0x210 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
xchk_dir_walk+0xb8/0x190 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
xchk_parent_count_parent_dentries+0x41/0x80 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
xchk_parent_validate+0x199/0x2e0 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
xchk_parent+0xdf/0x130 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
xfs_scrub_metadata+0x2b8/0x730 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
xfs_scrubv_metadata+0x38b/0x4d0 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
xfs_ioc_scrubv_metadata+0x111/0x160 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
xfs_file_ioctl+0x367/0xf50 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd]
__x64_sys_ioctl+0x82/0xa0
do_syscall_64+0x2b/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

The cause of this is a race condition in xfs_ilock_data_map_shared,
which performs an unlocked access to the data fork to guess which lock
mode it needs:

Thread 0                          Thread 1

xfs_need_iread_extents
<observe no iext tree>
xfs_ilock(..., ILOCK_EXCL)
xfs_iread_extents
<observe no iext tree>
<check ILOCK_EXCL>
<load bmbt extents into iext>
<notice iext size doesn't
match nextents>
                                  xfs_need_iread_extents
                                  <observe iext tree>
                                  xfs_ilock(..., ILOCK_SHARED)
<tear down iext tree>
xfs_iunlock(..., ILOCK_EXCL)
                                  xfs_iread_extents
                                  <observe no iext tree>
                                  <check ILOCK_EXCL>
                                  *BOOM*

Fix this race by adding a flag to the xfs_ifork structure to indicate
that we have not yet read in the extent records and changing the
predicate to look at the flag state, not if_height.  The memory barrier
ensures that the flag will not be set until the very end of the
function.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: remove WARN when dquot cache insertion fails

It just creates unnecessary bot noise these days.

Reported-by: syzbot+6ae213503fb12e87934f@syzkaller.appspotmail.com
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: don't consider future format versions valid

In commit fe08cc504448 we reworked the valid superblock version
checks. If it is a V5 filesystem, it is always valid, then we
checked if the version was less than V4 (reject) and then checked
feature fields in the V4 flags to determine if it was valid.

What we missed was that if the version is not V4 at this point,
we shoudl reject the fs. i.e. the check current treats V6+
filesystems as if it was a v4 filesystem. Fix this.

cc: stable@vger.kernel.org
Fixes: fe08cc504448 ("xfs: open code sb verifier feature checks")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

xfs: complain about bad file mapping records in the ondisk bmbt

Similar to what we've just done for the other btrees, create a function
to log corrupt bmbt records and call it whenever we encounter a bad
record in the ondisk btree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: complain about bad records in query_range helpers

For every btree type except for the bmbt, refactor the code that
complains about bad records into a helper and make the ->query_range
helpers call it so that corruptions found via that avenue are logged.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: standardize ondisk to incore conversion for bmap btrees

Fix all xfs_bmbt_disk_get_all callsites to call xfs_bmap_validate_extent
and bubble up corruption reports.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: standardize ondisk to incore conversion for rmap btrees

Create a xfs_rmap_check_irec function to detect corruption in btree
records. Fix all xfs_rmap_btrec_to_irec callsites to call the new
helper and bubble up corruption reports.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: return a failure address from xfs_rmap_irec_offset_unpack

Currently, xfs_rmap_irec_offset_unpack returns only 0 or -EFSCORRUPTED.
Change this function to return the code address of a failed conversion
in preparation for the next patch, which standardizes localized record
checking and reporting code.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: standardize ondisk to incore conversion for refcount btrees

Create a xfs_refcount_check_irec function to detect corruption in btree
records. Fix all xfs_refcount_btrec_to_irec callsites to call the new
helper and bubble up corruption reports.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: standardize ondisk to incore conversion for inode btrees

Create a xfs_inobt_check_irec function to detect corruption in btree
records. Fix all xfs_inobt_btrec_to_irec callsites to call the new
helper and bubble up corruption reports.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: standardize ondisk to incore conversion for free space btrees

Create a xfs_alloc_btrec_to_irec function to convert an ondisk record to
an incore record, and a xfs_alloc_check_irec function to detect
corruption. Replace all the open-coded logic with calls to the new
helpers and bubble up corruption reports.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: scrub should use ECHRNG to signal that the drain is needed

In the previous patch, we added jump labels to the intent drain code so
that regular filesystem operations need not pay the price of checking
for someone (scrub) waiting on intents to drain from some part of the
filesystem when that someone isn't running.

However, I observed that xfs/285 now spends a lot more time pushing the
AIL from the inode btree scrubber than it used to. This is because the
inobt scrubber will try push the AIL to try to get logged inode cores
written to the filesystem when it sees a weird discrepancy between the
ondisk inode and the inobt records. This AIL push is triggered when the
setup function sees TRY_HARDER is set; and the requisite EDEADLOCK
return is initiated when the discrepancy is seen.

The solution to this performance slow down is to use a different result
code (ECHRNG) for scrub code to signal that it needs to wait for
deferred intent work items to drain out of some part of the filesystem.
When this happens, set a new scrub state flag (XCHK_NEED_DRAIN) so that
setup functions will activate the jump label.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: minimize overhead of drain wakeups by using jump labels

To reduce the runtime overhead even further when online fsck isn't
running, use a static branch key to decide if we call wake_up on the
drain.  For compilers that support jump labels, the call to wake_up is
replaced by a nop sled when nobody is waiting for intents to drain.

From my initial microbenchmarking, every transition of the static key
between the on and off states takes about 22000ns to complete; this is
paid entirely by the xfs_scrub process.  When the static key is off
(which it should be when fsck isn't running), the nop sled adds an
overhead of approximately 0.36ns to runtime code.  The post-atomic
lockless waiter check adds about 0.03ns, which is basically free.

For the few compilers that don't support jump labels, runtime code pays
the cost of calling wake_up on an empty waitqueue, which was observed to
be about 30ns.  However, most architectures that have sufficient memory
and CPU capacity to run XFS also support jump labels, so this is not
much of a worry.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: clean up scrub context if scrub setup returns -EDEADLOCK

It has been a longstanding convention that online scrub and repair
functions can return -EDEADLOCK to signal that they weren't able to
obtain some necessary resource.  When this happens, the scrub framework
is supposed to release all resources attached to the scrub context, set
the TRY_HARDER flag in the scrub context flags, and try again.  In this
context, individual scrub functions are supposed to take all the
resources they (incorrectly) speculated were not necessary.

We're about to make it so that the functions that lock and wait for a
filesystem AG can also return EDEADLOCK to signal that we need to try
again with the drain waiters enabled.  Therefore, refactor
xfs_scrub_metadata to support this behavior for ->setup() functions.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: allow queued AG intents to drain before scrubbing

When a writer thread executes a chain of log intent items, the AG header
buffer locks will cycle during a transaction roll to get from one intent
item to the next in a chain.  Although scrub takes all AG header buffer
locks, this isn't sufficient to guard against scrub checking an AG while
that writer thread is in the middle of finishing a chain because there's
no higher level locking primitive guarding allocation groups.

When there's a collision, cross-referencing between data structures
(e.g. rmapbt and refcountbt) yields false corruption events; if repair
is running, this results in incorrect repairs, which is catastrophic.

Fix this by adding to the perag structure the count of active intents
and make scrub wait until it has both AG header buffer locks and the
intent counter reaches zero.

One quirk of the drain code is that deferred bmap updates also bump and
drop the intent counter.  A fundamental decision made during the design
phase of the reverse mapping feature is that updates to the rmapbt
records are always made by the same code that updates the primary
metadata.  In other words, callers of bmapi functions expect that the
bmapi functions will queue deferred rmap updates.

Some parts of the reflink code queue deferred refcount (CUI) and bmap
(BUI) updates in the same head transaction, but the deferred work
manager completely finishes the CUI before the BUI work is started.  As
a result, the CUI drops the intent count long before the deferred rmap
(RUI) update even has a chance to bump the intent count.  The only way
to keep the intent count elevated between the CUI and RUI is for the BUI
to bump the counter until the RUI has been created.

A second quirk of the intent drain code is that deferred work items must
increment the intent counter as soon as the work item is added to the
transaction.  When a BUI completes and queues an RUI, the RUI must
increment the counter before the BUI decrements it.  The only way to
accomplish this is to require that the counter be bumped as soon as the
deferred work item is created in memory.

In the next patches we'll improve on this facility, but this patch
provides the basic functionality.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: add a tracepoint to report incorrect extent refcounts

Add a new tracepoint so that I can see exactly what and where we failed
the refcount check.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: update copyright years for scrub/ files

Update the copyright years in the scrub/ source code files. This isn't
required, but it's helpful to remind myself just how long it's taken to
develop this feature.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: fix author and spdx headers on scrub/ files

Fix the spdx tags to match current practice, and update the author
contact information.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: create traced helper to get extra perag references

There are a few places in the XFS codebase where a caller has either an
active or a passive reference to a perag structure and wants to give
a passive reference to some other piece of code.  Btree cursor creation
and inode walks are good examples of this.  Replace the open-coded logic
with a helper to do this.

The new function adds a few safeguards -- it checks that there's at
least one reference to the perag structure passed in, and it records the
refcount bump in the ftrace information.  This makes it much easier to
debug perag refcounting problems.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: give xfs_refcount_intent its own perag reference

Give the xfs_refcount_intent a passive reference to the perag structure
data. This reference will be used to enable scrub intent draining
functionality in subsequent patches. Any space being modified by a
refcount intent is already allocated, so we need to be able to operate
even if the AG is being shrunk or offlined.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: give xfs_rmap_intent its own perag reference

Give the xfs_rmap_intent a passive reference to the perag structure
data. This reference will be used to enable scrub intent draining
functionality in subsequent patches. The space we're (reverse) mapping
is already allocated, so we need to be able to operate even if the AG is
being shrunk or offlined.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: give xfs_extfree_intent its own perag reference

Give the xfs_extfree_intent an passive reference to the perag structure
data. This reference will be used to enable scrub intent draining
functionality in subsequent patches. The space being freed must already
be allocated, so we need to able to run even if the AG is being offlined
or shrunk.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: pass per-ag references to xfs_free_extent

Pass a reference to the per-AG structure to xfs_free_extent. Most
callers already have one, so we can eliminate unnecessary lookups. The
one exception to this is the EFI code, which the next patch will fix.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: give xfs_bmap_intent its own perag reference

Give the xfs_bmap_intent an active reference to the perag structure
data.  This reference will be used to enable scrub intent draining
functionality in subsequent patches.  Later, shrink will use these
passive references to know if an AG is quiesced or not.

The reason why we take a passive ref for a file mapping operation is
simple: we're committing to some sort of action involving space in an
AG, so we want to indicate our interest in that AG.  The space is
already allocated, so we need to be able to operate on AGs that are
offline or being shrunk.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document future directions of online fsck

Add the seventh and final chapter of the online fsck documentation,
where we talk about future functionality that can tie in with the
functionality provided by the online fsck patchset.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document the userspace fsck driver program

Add the sixth chapter of the online fsck design documentation, where
we discuss the details of the data structures and algorithms used by the
driver program xfs_scrub.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document directory tree repairs

Directory tree repairs are the least complete part of online fsck, due
to the lack of directory parent pointers. However, even without that
feature, we can still make some corrections to the directory tree -- we
can salvage as many directory entries as we can from a damaged
directory, and we can reattach orphaned inodes to the lost+found, just
as xfs_repair does now.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document metadata file repair

File-based metadata (such as xattrs and directories) can be extremely
large. To reduce the memory requirements and maximize code reuse, it is
very convenient to create a temporary file, use the regular dir/attr
code to store salvaged information, and then atomically swap the extents
between the file being repaired and the temporary file. Record the high
level concepts behind how temporary files and atomic content swapping
should work, and then present some case studies of what the actual
repair functions do.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document full filesystem scans for online fsck

Certain parts of the online fsck code need to scan every file in the
entire filesystem. It is not acceptable to block the entire filesystem
while this happens, which means that we need to be clever in allowing
scans to coordinate with ongoing filesystem updates. We also need to
hook the filesystem so that regular updates propagate to the staging
records.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document online file metadata repair code

Add to the fifth chapter of the online fsck design documentation, where
we discuss the details of the data structures and algorithms used by the
kernel to repair file metadata.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document btree bulk loading

Add a discussion of the btree bulk loading code, which makes it easy to
take an in-memory recordset and write it out to disk in an efficient
manner. This also enables atomic switchover from the old to the new
structure with minimal potential for leaking the old blocks.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document pageable kernel memory

Add a discussion of pageable kernel memory, since online fsck needs
quite a bit more memory than most other parts of the filesystem to stage
records and other information.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document how online fsck deals with eventual consistency

Writes to an XFS filesystem employ an eventual consistency update model
to break up complex multistep metadata updates into small chained
transactions. This is generally good for performance and scalability
because XFS doesn't need to prepare for enormous transactions, but it
also means that online fsck must be careful not to attempt a fsck action
unless it can be shown that there are no other threads processing a
transaction chain. This part of the design documentation covers the
thinking behind the consistency model and how scrub deals with it.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document the filesystem metadata checking strategy

Begin the fifth chapter of the online fsck design documentation, where
we discuss the details of the data structures and algorithms used by the
kernel to examine filesystem metadata and cross-reference it around the
filesystem.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document the user interface for online fsck

Start the fourth chapter of the online fsck design documentation, which
discusses the user interface and the background scrubbing service.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document the testing plan for online fsck

Start the third chapter of the online fsck design documentation. This
covers the testing plan to make sure that both online and offline fsck
can detect arbitrary problems and correct them without making things
worse.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document the general theory underlying online fsck design

Start the second chapter of the online fsck design documentation.
This covers the general theory underlying how online fsck works.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

xfs: document the motivation for online fsck design

Start the first chapter of the online fsck design documentation.
This covers the motivations for creating this in the first place.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

Linux 6.3-rc6

Merge tag 'perf_urgent_for_v6.3_rc6' of git://git./linux/kernel/git/tip/tip

Pull perf fixes from Borislav Petkov:

- Fix "same task" check when redirecting event output

- Do not wait unconditionally for RCU on the event migration path if
   there are no events to migrate

* tag 'perf_urgent_for_v6.3_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix the same task check in perf_event_set_output
  perf: Optimize perf_pmu_migrate_context()

Merge tag 'x86_urgent_for_v6.3_rc6' of git://git./linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

- Add a new Intel Arrow Lake CPU model number

- Fix a confusion about how to check the version of the ACPI spec which
   supports a "online capable" bit in the MADT table which lead to a
   bunch of boot breakages with Zen1 systems and VMs

* tag 'x86_urgent_for_v6.3_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu: Add model number for Intel Arrow Lake processor
  x86/acpi/boot: Correct acpi_is_processor_usable() check
  x86/ACPI/boot: Use FADT version to check support for online capable

Merge tag 'cxl-fixes-6.3-rc6' of git://git./linux/kernel/git/cxl/cxl

Pull compute express link (cxl) fixes from Dan Williams:
"Several fixes for driver startup regressions that landed during the
  merge window as well as some older bugs.

  The regressions were due to a lack of testing with what the CXL
  specification calls Restricted CXL Host (RCH) topologies compared to
  the testing with Virtual Host (VH) CXL topologies. A VH topology is
  typical PCIe while RCH topologies map CXL endpoints as Root Complex
  Integrated endpoints. The impact is some driver crashes on startup.

  This merge window also added compatibility for range registers (the
  mechanism that CXL 1.1 defined for mapping memory) to treat them like
  HDM decoders (the mechanism that CXL 2.0 defined for mapping
  Host-managed Device Memory). That work collided with the new region
  enumeration code that was tested with CXL 2.0 setups, and fails with
  crashes at startup.

  Lastly, the DOE (Data Object Exchange) implementation for retrieving
  an ACPI-like data table from CXL devices is being reworked for v6.4.
  Several fixes fell out of that work that are suitable for v6.3.

  All of this has been in linux-next for a while, and all reported
  issues [1] have been addressed.

  Summary:

   - Fix several issues with region enumeration in RCH topologies that
     can trigger crashes on driver startup or shutdown.

   - Fix CXL DVSEC range register compatibility versus region
     enumeration that leads to startup crashes

   - Fix CDAT endiannes handling

   - Fix multiple buffer handling boundary conditions

   - Fix Data Object Exchange (DOE) workqueue usage vs
     CONFIG_DEBUG_OBJECTS warn splats"

Link: http://lore.kernel.org/r/20230405075704.33de8121@canb.auug.org.au
* tag 'cxl-fixes-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
  cxl/hdm: Extend DVSEC range register emulation for region enumeration
  cxl/hdm: Limit emulation to the number of range registers
  cxl/region: Move coherence tracking into cxl_region_attach()
  cxl/region: Fix region setup/teardown for RCDs
  cxl/port: Fix find_cxl_root() for RCDs and simplify it
  cxl/hdm: Skip emulation when driver manages mem_enable
  cxl/hdm: Fix double allocation of @cxlhdm
  PCI/DOE: Fix memory leak with CONFIG_DEBUG_OBJECTS=y
  PCI/DOE: Silence WARN splat with CONFIG_DEBUG_OBJECTS=y
  cxl/pci: Handle excessive CDAT length
  cxl/pci: Handle truncated CDAT entries
  cxl/pci: Handle truncated CDAT header
  cxl/pci: Fix CDAT retrieval on big endian

Merge tag '6.3-rc5-smb3-cifs-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs client fixes from Steve French:
"Two cifs/smb3 client fixes, one for stable:

   - double lock fix for a cifs/smb1 reconnect path

   - DFS prefixpath fix for reconnect when server moved"

* tag '6.3-rc5-smb3-cifs-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: double lock in cifs_reconnect_tcon()
  cifs: sanitize paths in cifs_update_super_prepath.

Merge tag 'char-misc-6.3-rc6' of git://git./linux/kernel/git/gregkh/char-misc

Pull char/misc driver fixes from Greg KH:
"Here are a small set of various small driver changes for 6.3-rc6.
  Included in here are:

   - iio driver fixes for reported problems

   - coresight hwtracing bugfix for reported problem

   - small counter driver bugfixes

  All have been in linux-next for a while with no reported problems"

* tag 'char-misc-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  coresight: etm4x: Do not access TRCIDR1 for identification
  coresight-etm4: Fix for() loop drvdata->nr_addr_cmp range bug
  iio: adc: ti-ads7950: Set `can_sleep` flag for GPIO chip
  iio: adc: palmas_gpadc: fix NULL dereference on rmmod
  counter: 104-quad-8: Fix Synapse action reported for Index signals
  counter: 104-quad-8: Fix race condition between FLAG and CNTR reads
  iio: adc: max11410: fix read_poll_timeout() usage
  iio: dac: cio-dac: Fix max DAC write value check for 12-bit
  iio: light: cm32181: Unregister second I2C client if present
  iio: accel: kionix-kx022a: Get the timestamp from the driver's private data in the trigger_handler
  iio: adc: ad7791: fix IRQ flags
  iio: buffer: make sure O_NONBLOCK is respected
  iio: buffer: correctly return bytes written in output buffers
  iio: light: vcnl4000: Fix WARN_ON on uninitialized lock
  iio: adis16480: select CONFIG_CRC32
  drivers: iio: adc: ltc2497: fix LSB shift
  iio: adc: qcom-spmi-adc5: Fix the channel name

Merge tag 'tty-6.3-rc6' of git://git./linux/kernel/git/gregkh/tty

Pull tty/serial driver fixes from Greg KH:
"Here are some small tty and serial driver fixes for some reported
  problems:

   - fsl_uart driver bugfixes

   - sh-sci serial driver bugfixes

   - renesas serial driver DT binding bugfixes

   - 8250 DMA bugfix

  All of these have been in linux-next for a while with no reported
  problems"

* tag 'tty-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: serial: sh-sci: Fix Rx on RZ/G2L SCI
  tty: serial: fsl_lpuart: fix crash in lpuart_uport_is_active
  tty: serial: fsl_lpuart: avoid checking for transfer complete when UARTCTRL_SBK is asserted in lpuart32_tx_empty
  serial: 8250: Prevent starting up DMA Rx on THRI interrupt
  dt-bindings: serial: renesas,scif: Fix 4th IRQ for 4-IRQ SCIFs
  tty: serial: sh-sci: Fix transmit end interrupt handler

Merge tag 'usb-6.3-rc6' of git://git./linux/kernel/git/gregkh/usb

Pull USB bugfixes from Greg KH:
"Here are some small USB bugfixes for 6.3-rc6 that have been in my
  tree, and in linux-next, for a while. Included in here are:

   - new usb-serial driver device ids

   - xhci bugfixes for reported problems

   - gadget driver bugfixes for reported problems

   - dwc3 new device id

  All have been in linux-next with no reported problems"

* tag 'usb-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: cdnsp: Fixes error: uninitialized symbol 'len'
  usb: gadgetfs: Fix ep_read_iter to handle ITER_UBUF
  usb: gadget: f_fs: Fix ffs_epfile_read_iter to handle ITER_UBUF
  usb: typec: altmodes/displayport: Fix configure initial pin assignment
  usb: dwc3: pci: add support for the Intel Meteor Lake-S
  xhci: Free the command allocated for setting LPM if we return early
  Revert "usb: xhci-pci: Set PROBE_PREFER_ASYNCHRONOUS"
  xhci: also avoid the XHCI_ZERO_64B_REGS quirk with a passthrough iommu
  USB: serial: option: add Quectel RM500U-CN modem
  usb: xhci: tegra: fix sleep in atomic call
  USB: serial: option: add Telit FE990 compositions
  USB: serial: cp210x: add Silicon Labs IFS-USB-DATACABLE IDs

Merge tag 'scsi-fixes' of git://git./linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
"Four small fixes, all in drivers. They're all one or two lines except
  for the ufs one, but that's a simple revert of a previous feature"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: iscsi_tcp: Check that sock is valid before iscsi_set_param()
  scsi: qla2xxx: Fix memory leak in qla2x00_probe_one()
  scsi: mpi3mr: Handle soft reset in progress fault code (0xF002)
  scsi: Revert "scsi: ufs: core: Initialize devfreq synchronously"

Merge tag 'block-6.3-2023-04-06' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:

- Ensure that ublk always reads the whole sqe upfront (me)

- Fix for a block size probing issue with ublk (Ming)

- Fix for the bio based polling (Keith)

- NVMe pull request via Christoph:
      - fix discard support without oncs (Keith Busch)

- Partition scan error handling regression fix (Yu)

* tag 'block-6.3-2023-04-06' of git://git.kernel.dk/linux:
  block: don't set GD_NEED_PART_SCAN if scan partition failed
  block: ublk: make sure that block size is set correctly
  ublk: read any SQE values upfront
  nvme: fix discard support without oncs
  blk-mq: directly poll requests

Merge tag 'io_uring-6.3-2023-04-06' of git://git.kernel.dk/linux

Pull io_uring fixes from Jens Axboe:
"Just two minor fixes for provided buffers - one where we could
  potentially leak a buffer, and one where the returned values was
  off-by-one in some cases"

* tag 'io_uring-6.3-2023-04-06' of git://git.kernel.dk/linux:
  io_uring: fix memory leak when removing provided buffers
  io_uring: fix return value when removing provided buffers

Merge tag 'dma-mapping-6.3-2023-04-08' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fix from Christoph Hellwig:

- fix a braino in the swiotlb alignment check fix (Petr Tesarik)

* tag 'dma-mapping-6.3-2023-04-08' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: fix a braino in the alignment check fix

Merge tag 'trace-v6.3-rc5-2' of git://git./linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:
"A couple more minor fixes:

   - Reset direct->addr back to its original value on error in updating
     the direct trampoline code

   - Make lastcmd_mutex static"

* tag 'trace-v6.3-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/synthetic: Make lastcmd_mutex static
  ftrace: Fix issue that 'direct->addr' not restored in modify_ftrace_direct()

Merge tag 'mm-hotfixes-stable-2023-04-07-16-23' of git://git./linux/kernel/git/akpm/mm

Pull MM fixes from Andrew Morton:
"28 hotfixes.

  23 are cc:stable and the other five address issues which were
  introduced during this merge cycle.

  20 are for MM and the remainder are for other subsystems"

* tag 'mm-hotfixes-stable-2023-04-07-16-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (28 commits)
  maple_tree: fix a potential concurrency bug in RCU mode
  maple_tree: fix get wrong data_end in mtree_lookup_walk()
  mm/swap: fix swap_info_struct race between swapoff and get_swap_pages()
  nilfs2: fix sysfs interface lifetime
  mm: take a page reference when removing device exclusive entries
  mm: vmalloc: avoid warn_alloc noise caused by fatal signal
  nilfs2: initialize "struct nilfs_binfo_dat"->bi_pad field
  nilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread()
  zsmalloc: document freeable stats
  zsmalloc: document new fullness grouping
  fsdax: force clear dirty mark if CoW
  mm/hugetlb: fix uffd wr-protection for CoW optimization path
  mm: enable maple tree RCU mode by default
  maple_tree: add RCU lock checking to rcu callback functions
  maple_tree: add smp_rmb() to dead node detection
  maple_tree: fix write memory barrier of nodes once dead for RCU mode
  maple_tree: remove extra smp_wmb() from mas_dead_leaves()
  maple_tree: fix freeing of nodes in rcu mode
  maple_tree: detect dead nodes in mas_start()
  maple_tree: be more cautious about dead nodes
  ...

Merge tag 'gpio-fixes-for-v6.3-rc6' of git://git./linux/kernel/git/brgl/linux

Pull gpio fixes from Bartosz Golaszewski:

- fix irq handling in gpio-davinci

- fix Kconfig dependencies for gpio-regmap

* tag 'gpio-fixes-for-v6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpio: davinci: Add irq chip flag to skip set wake
  gpio: davinci: Do not clear the bank intr enable bit in save_context
  gpio: GPIO_REGMAP: select REGMAP instead of depending on it

Merge tag 'acpi-6.3-rc6' of git://git./linux/kernel/git/rafael/linux-pm

Pull ACPI fixes from Rafael Wysocki:
"Fix the ACPI backlight override mechanism for the cases when
  acpi_backlight=video is set through the kernel command line or a DMI
  quirk and add backlight quirks for Apple iMac14,1 and iMac14,2 and
  Lenovo ThinkPad W530 (Hans de Goede)"

* tag 'acpi-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: video: Add acpi_backlight=video quirk for Lenovo ThinkPad W530
  ACPI: video: Add acpi_backlight=video quirk for Apple iMac14,1 and iMac14,2
  ACPI: video: Make acpi_backlight=video work independent from GPU driver
  ACPI: video: Add auto_detect arg to __acpi_video_get_backlight_type()

Merge tag 'arm64-fixes' of git://git./linux/kernel/git/arm64/linux

Pull arm64 fix from Catalin Marinas:
"Fix uninitialised variable warning (from smatch) in the arm64 compat
alignment fixup code"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: compat: Work around uninitialized variable warning

Merge tag '6.3-rc5-ksmbd-server-fixes' of git://git.samba.org/ksmbd

Pull ksmbd server fixes from Steve French:
"Four fixes, three for stable:

   - slab out of bounds fix

   - lock cancellation fix

   - minor cleanup to address clang warning

   - fix for xfstest 551 (wrong parms passed to kvmalloc)"

* tag '6.3-rc5-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
  ksmbd: fix slab-out-of-bounds in init_smb2_rsp_hdr
  ksmbd: delete asynchronous work from list
  ksmbd: remove unused is_char_allowed function
  ksmbd: do not call kvmalloc() with __GFP_NORETRY | __GFP_NO_WARN

cifs: double lock in cifs_reconnect_tcon()

This lock was supposed to be an unlock.

Fixes: 6cc041e90c17 ("cifs: avoid races in parallel reconnects in smb1")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

block: don't set GD_NEED_PART_SCAN if scan partition failed

Currently if disk_scan_partitions() failed, GD_NEED_PART_SCAN will still
set, and partition scan will be proceed again when blkdev_get_by_dev()
is called. However, this will cause a problem that re-assemble partitioned
raid device will creat partition for underlying disk.

Test procedure:

mdadm -CR /dev/md0 -l 1 -n 2 /dev/sda /dev/sdb -e 1.0
sgdisk -n 0:0:+100MiB /dev/md0
blockdev --rereadpt /dev/sda
blockdev --rereadpt /dev/sdb
mdadm -S /dev/md0
mdadm -A /dev/md0 /dev/sda /dev/sdb

Test result: underlying disk partition and raid partition can be
observed at the same time

Note that this can still happen in come corner cases that
GD_NEED_PART_SCAN can be set for underlying disk while re-assemble raid
device.

Fixes: e5cfefa97bcc ("block: fix scan partition for exclusively open device again")
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

tracing/synthetic: Make lastcmd_mutex static

The lastcmd_mutex is only used in trace_events_synth.c and should be
static.

Link: https://lore.kernel.org/linux-trace-kernel/202304062033.cRStgOuP-lkp@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20230406111033.6e26de93@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Tze-nan Wu <Tze-nan.Wu@mediatek.com>
Fixes: 4ccf11c4e8a8e ("tracing/synthetic: Fix races on freeing last_cmd")
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Merge tag 'net-6.3-rc6-2' of git://git./linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
"Including fixes from wireless and can.

  Current release - regressions:

   - wifi: mac80211:
      - fix potential null pointer dereference
      - fix receiving mesh packets in forwarding=0 networks
      - fix mesh forwarding

  Current release - new code bugs:

   - virtio/vsock: fix leaks due to missing skb owner

  Previous releases - regressions:

   - raw: fix NULL deref in raw_get_next().

   - sctp: check send stream number after wait_for_sndbuf

   - qrtr:
      - fix a refcount bug in qrtr_recvmsg()
      - do not do DEL_SERVER broadcast after DEL_CLIENT

   - wifi: brcmfmac: fix SDIO suspend/resume regression

   - wifi: mt76: fix use-after-free in fw features query.

   - can: fix race between isotp_sendsmg() and isotp_release()

   - eth: mtk_eth_soc: fix remaining throughput regression

   - eth: ice: reset FDIR counter in FDIR init stage

  Previous releases - always broken:

   - core: don't let netpoll invoke NAPI if in xmit context

   - icmp: guard against too small mtu

   - ipv6: fix an uninit variable access bug in __ip6_make_skb()

   - wifi: mac80211: fix the size calculation of
     ieee80211_ie_len_eht_cap()

   - can: fix poll() to not report false EPOLLOUT events

   - eth: gve: secure enough bytes in the first TX desc for all TCP
     pkts"

* tag 'net-6.3-rc6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (47 commits)
  net: stmmac: check fwnode for phy device before scanning for phy
  net: stmmac: Add queue reset into stmmac_xdp_open() function
  selftests: net: rps_default_mask.sh: delete veth link specifically
  net: fec: make use of MDIO C45 quirk
  can: isotp: fix race between isotp_sendsmg() and isotp_release()
  can: isotp: isotp_ops: fix poll() to not report false EPOLLOUT events
  can: isotp: isotp_recvmsg(): use sock_recv_cmsgs() to get SOCK_RXQ_OVFL infos
  can: j1939: j1939_tp_tx_dat_new(): fix out-of-bounds memory access
  gve: Secure enough bytes in the first TX desc for all TCP pkts
  netlink: annotate lockless accesses to nlk->max_recvmsg_len
  ethtool: reset #lanes when lanes is omitted
  ping: Fix potentail NULL deref for /proc/net/icmp.
  raw: Fix NULL deref in raw_get_next().
  ice: Reset FDIR counter in FDIR init stage
  ice: fix wrong fallback logic for FDIR
  net: stmmac: fix up RX flow hash indirection table when setting channels
  net: ethernet: ti: am65-cpsw: Fix mdio cleanup in probe
  wifi: mt76: ignore key disable commands
  wifi: ath11k: reduce the MHI timeout to 20s
  ipv6: Fix an uninit variable access bug in __ip6_make_skb()
  ...

Merge tag 'linux-kselftest-fixes-6.3-rc6' of git://git./linux/kernel/git/shuah/linux-kselftest

Pull Kselftest fixes from Shuah Khan:
"One single fix to mount_setattr_test build failure"

* tag 'linux-kselftest-fixes-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests mount: Fix mount_setattr_test builds failed

Merge tag 'for-linus-iommufd' of git://git./linux/kernel/git/jgg/iommufd

Pull iommufd fixes from Jason Gunthorpe:

- An invalid VA range can be be put in a pages and eventually trigger
   WARN_ON, reject it early

- Use of the wrong start index value when doing the complex batch carry
   scheme

- Wrong store ordering resulting in corrupting data used in a later
   calculation that corrupted the batch structure during carry

* tag 'for-linus-iommufd' of git://git.kernel.org/pub/scm/linux/kernel/git/jgg/iommufd:
  iommufd: Do not corrupt the pfn list when doing batch carry
  iommufd: Fix unpinning of pages when an access is present
  iommufd: Check for uptr overflow

Merge tag 'pwm/for-6.3-rc6' of git://git./linux/kernel/git/thierry.reding/linux-pwm

Pull pwm fixes from Thierry Reding:
"These are some fixes to make sure the PWM state structure is always
  initialized to a known state.

  Prior to this it could happen in some situations that random data from
  the stack would leak into the data structure and cause subtle bugs"

* tag 'pwm/for-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  pwm: Zero-initialize the pwm_state passed to driver's .get_state()
  pwm: meson: Explicitly set .polarity in .get_state()
  pwm: sprd: Explicitly set .polarity in .get_state()
  pwm: iqs620a: Explicitly set .polarity in .get_state()
  pwm: cros-ec: Explicitly set .polarity in .get_state()
  pwm: hibvt: Explicitly set .polarity in .get_state()

Merge tag 'drm-fixes-2023-04-06' of git://anongit.freedesktop.org/drm/drm

Pull drm fixes from Daniel Vetter:
"Mostly i915 fixes: dp mst for compression/dsc, perf ioctl uaf, ctx rpm
  accounting, gt reset vs huc loading.

  And a few individual driver fixes: ivpu dma fence&suspend, panfrost
  mmap, nouveau color depth"

* tag 'drm-fixes-2023-04-06' of git://anongit.freedesktop.org/drm/drm:
  accel/ivpu: Fix S3 system suspend when not idle
  accel/ivpu: Add dma fence to command buffers only
  drm/i915: Fix context runtime accounting
  drm/i915: fix race condition UAF in i915_perf_add_config_ioctl
  drm/i915: Use compressed bpp when calculating m/n value for DP MST DSC
  drm/i915/huc: Cancel HuC delayed load timer on reset.
  drm/i915/ttm: fix sparse warning
  drm/panfrost: Fix the panfrost_mmu_map_fault_addr() error path
  drm/nouveau/disp: Support more modes by checking with lower bpc

Merge tag 'sound-6.3-rc6' of git://git./linux/kernel/git/tiwai/sound

Pull sound fixes from Takashi Iwai:
"The majority of changes here are various fixes for Intel drivers,
  and there is a change in ASoC PCM core for the format constraints.

  In addition, a workaround for HD-audio HDMI regressions and usual
  HD-audio quirks are found"

* tag 'sound-6.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda/hdmi: Preserve the previous PCM device upon re-enablement
  ALSA: hda/realtek: Add quirk for Clevo X370SNW
  ALSA: hda/realtek: fix mute/micmute LEDs for a HP ProBook
  ASoC: SOF: avoid a NULL dereference with unsupported widgets
  ASoC: da7213.c: add missing pm_runtime_disable()
  ASoC: hdac_hdmi: use set_stream() instead of set_tdm_slots()
  ASoC: codecs: lpass: fix the order or clks turn off during suspend
  ASoC: Intel: bytcr_rt5640: Add quirk for the Acer Iconia One 7 B1-750
  ASoC: SOF: ipc4: Ensure DSP is in D0I0 during sof_ipc4_set_get_data()
  ASoC: amd: yc: Add DMI entries to support Victus by HP Laptop 16-e1xxx (8A22)
  ASoC: soc-pcm: fix hw->formats cleared by soc_pcm_hw_init() for dpcm
  ASoC: Intel: soc-acpi: add table for Intel 'Rooks County' NUC M15
  ASOC: Intel: sof_sdw: add quirk for Intel 'Rooks County' NUC M15

Merge tag 'platform-drivers-x86-v6.3-5' of git://git./linux/kernel/git/pdx86/platform-drivers-x86

Pull x86 platform driver fixes from Hans de Goede:

-  more think-lmi fixes

-  one DMI quirk addition

* tag 'platform-drivers-x86-v6.3-5' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86:
  platform/x86: thinkpad_acpi: Add missing T14s Gen1 type to s2idle quirk list
  platform/x86: think-lmi: Clean up display of current_value on Thinkstation
  platform/x86: think-lmi: Fix memory leaks when parsing ThinkStation WMI strings
  platform/x86: think-lmi: Fix memory leak when showing current settings

Merge tag 'asm-generic-fixes-6.3' of git://git./linux/kernel/git/arnd/asm-generic

Pull asm-generic fixes from Arnd Bergmann:
"These are minor fixes to address false-positive build warnings:

  Some of the less common I/O accessors are missing __force casts and
  cause sparse warnings for their implied byteswap, and a recent change
  to __generic_cmpxchg_local() causes a warning about constant integer
  truncation"

* tag 'asm-generic-fixes-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  asm-generic: avoid __generic_cmpxchg_local warnings
  asm-generic/io.h: suppress endianness warnings for relaxed accessors
  asm-generic/io.h: suppress endianness warnings for readq() and writeq()

net: stmmac: check fwnode for phy device before scanning for phy

Some DT devices already have phy device configured in the DT/ACPI.
Current implementation scans for a phy unconditionally even though
there is a phy listed in the DT/ACPI and already attached.

We should check the fwnode if there is any phy device listed in
fwnode and decide whether to scan for a phy to attach to.

Fixes: fe2cfbc96803 ("net: stmmac: check if MAC needs to attach to a PHY")
Reported-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/lkml/20230403212434.296975-1-martin.blumenstingl@googlemail.com/
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Shahab Vahedi <shahab@synopsys.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Suggested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
Link: https://lore.kernel.org/r/20230406024541.3556305-1-michael.wei.hong.sit@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ftrace: Fix issue that 'direct->addr' not restored in modify_ftrace_direct()

Syzkaller report a WARNING: "WARN_ON(!direct)" in modify_ftrace_direct().

Root cause is 'direct->addr' was changed from 'old_addr' to 'new_addr' but
not restored if error happened on calling ftrace_modify_direct_caller().
Then it can no longer find 'direct' by that 'old_addr'.

To fix it, restore 'direct->addr' to 'old_addr' explicitly in error path.

Link: https://lore.kernel.org/linux-trace-kernel/20230330025223.1046087-1-zhengyejian1@huawei.com
Cc: stable@vger.kernel.org
Cc: <mhiramat@kernel.org>
Cc: <mark.rutland@arm.com>
Cc: <ast@kernel.org>
Cc: <daniel@iogearbox.net>
Fixes: 8a141dd7f706 ("ftrace: Fix modify_ftrace_direct.")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

swiotlb: fix a braino in the alignment check fix

The alignment mask in swiotlb_do_find_slots() masks off the high
bits which are not relevant for the alignment, so multiple
requirements are combined with a bitwise OR rather than AND.
In plain English, the stricter the alignment, the more bits must
be set in iotlb_align_mask.

Confusion may arise from the fact that the same variable is also
used to mask off the offset within a swiotlb slot, which is
achieved with a bitwise AND.

Fixes: 0eee5ae10256 ("swiotlb: fix slot alignment checks")
Reported-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/all/CAA42JLa1y9jJ7BgQvXeUYQh-K2mDNHd2BYZ4iZUz33r5zY7oAQ@mail.gmail.com/
Reported-by: Kelsey Steele <kelseysteele@linux.microsoft.com>
Link: https://lore.kernel.org/all/20230405003549.GA21326@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net/
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Tested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Merge tag 'nvme-6.3-2023-04-06' of git://git.infradead.org/nvme into block-6.3

Pull NVMe fix from Christoph:

"nvme fixes for Linux 6.3

- fix discard support without oncs (Keith Busch)"

* tag 'nvme-6.3-2023-04-06' of git://git.infradead.org/nvme:
nvme: fix discard support without oncs

block: ublk: make sure that block size is set correctly

block size is one very key setting for block layer, and bad block size
could panic kernel easily.

Make sure that block size is set correctly.

Meantime if ublk_validate_params() fails, clear ub->params so that disk
is prevented from being added.

Fixes: 71f28f3136af ("ublk_drv: add io_uring based userspace block driver")
Reported-and-tested-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

ublk: read any SQE values upfront

Since SQE memory is shared with userspace, we should only be reading it
once. We cannot read it multiple times, particularly when it's read once
for validation and then read again for the actual use.

ublk_ch_uring_cmd() is safe when called as a retry operation, as the
memory backing is stable at that point. But for normal issue, we want
to ensure that we only read ublksrv_io_cmd once. Wrap the function in
a helper that reads the value into an on-stack copy of the struct.

Cc: stable@vger.kernel.org # 6.0+
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

net: stmmac: Add queue reset into stmmac_xdp_open() function

Queue reset was moved out from __init_dma_rx_desc_rings() and
__init_dma_tx_desc_rings() functions. Thus, the driver fails to transmit
and receive packet after XDP prog setup.

This commit adds the missing queue reset into stmmac_xdp_open() function.

Fixes: f9ec5723c3db ("net: ethernet: stmicro: stmmac: move queue reset to dedicated functions")
Cc: <stable@vger.kernel.org> # 6.0+
Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/20230404044823.3226144-1-yoong.siang.song@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: net: rps_default_mask.sh: delete veth link specifically

When deleting the netns and recreating a new one while re-adding the
veth interface, there is a small window of time during which the old
veth interface has not yet been removed. This can cause the new addition
to fail. To resolve this issue, we can either wait for a short while to
ensure that the old veth interface is deleted, or we can specifically
remove the veth interface.

Before this patch:
  # ./rps_default_mask.sh
  empty rps_default_mask                                      [ ok ]
  changing rps_default_mask dont affect existing devices      [ ok ]
  changing rps_default_mask dont affect existing netns        [ ok ]
  changing rps_default_mask affect newly created devices      [ ok ]
  changing rps_default_mask don't affect newly child netns[II][ ok ]
  rps_default_mask is 0 by default in child netns             [ ok ]
  RTNETLINK answers: File exists
  changing rps_default_mask in child ns don't affect the main one[ ok ]
  cat: /sys/class/net/vethC11an1/queues/rx-0/rps_cpus: No such file or directory
  changing rps_default_mask in child ns affects new childns devices./rps_default_mask.sh: line 36: [: -eq: unary operator expected
  [fail] expected 1 found
  changing rps_default_mask in child ns don't affect existing devices[ ok ]

After this patch:
  # ./rps_default_mask.sh
  empty rps_default_mask                                      [ ok ]
  changing rps_default_mask dont affect existing devices      [ ok ]
  changing rps_default_mask dont affect existing netns        [ ok ]
  changing rps_default_mask affect newly created devices      [ ok ]
  changing rps_default_mask don't affect newly child netns[II][ ok ]
  rps_default_mask is 0 by default in child netns             [ ok ]
  changing rps_default_mask in child ns don't affect the main one[ ok ]
  changing rps_default_mask in child ns affects new childns devices[ ok ]
  changing rps_default_mask in child ns don't affect existing devices[ ok ]

Fixes: 3a7d84eae03b ("self-tests: more rps self tests")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20230404072411.879476-1-liuhangbin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: fec: make use of MDIO C45 quirk

Not all fec MDIO bus drivers support C45 mode transactions. The older fec
hardware block in many ColdFire SoCs does not appear to support them, at
least according to most of the different ColdFire SoC reference manuals.
The bits used to generate C45 access on the iMX parts, in the OP field
of the MMFR register, are documented as generating non-compliant MII
frames (it is not documented as to exactly how they are non-compliant).

Commit 8d03ad1ab0b0 ("net: fec: Separate C22 and C45 transactions")
means the fec driver will always register c45 MDIO read and write
methods. During probe these will always be accessed now generating
non-compliant MII accesses on ColdFire based devices.

Add a quirk define, FEC_QUIRK_HAS_MDIO_C45, that can be used to
distinguish silicon that supports MDIO C45 framing or not. Add this to
all the existing iMX quirks, so they will be behave as they do now (*).

(*) it seems that some iMX parts may not support C45 transactions either.
The iMX25 and iMX50 Reference Manuals contain similar wording to
the ColdFire Reference Manuals on this.

Fixes: 8d03ad1ab0b0 ("net: fec: Separate C22 and C45 transactions")
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20230404052207.3064861-1-gerg@linux-m68k.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

maple_tree: fix a potential concurrency bug in RCU mode

There is a concurrency bug that may cause the wrong value to be loaded
when a CPU is modifying the maple tree.

CPU1:
mtree_insert_range()
  mas_insert()
    mas_store_root()
      ...
      mas_root_expand()
        ...
        rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node));
        ma_set_meta(node, maple_leaf_64, 0, slot);    <---IP

CPU2:
mtree_load()
  mtree_lookup_walk()
    ma_data_end();

When CPU1 is about to execute the instruction pointed to by IP, the
ma_data_end() executed by CPU2 may return the wrong end position, which
will cause the value loaded by mtree_load() to be wrong.

An example of triggering the bug:

Add mdelay(100) between rcu_assign_pointer() and ma_set_meta() in
mas_root_expand().

static DEFINE_MTREE(tree);
int work(void *p) {
unsigned long val;
for (int i = 0 ; i< 30; ++i) {
val = (unsigned long)mtree_load(&tree, 8);
mdelay(5);
pr_info("%lu",val);
}
return 0;
}

mt_init_flags(&tree, MT_FLAGS_USE_RCU);
mtree_insert(&tree, 0, (void*)12345, GFP_KERNEL);
run_thread(work)
mtree_insert(&tree, 1, (void*)56789, GFP_KERNEL);

In RCU mode, mtree_load() should always return the value before or after
the data structure is modified, and in this example mtree_load(&tree, 8)
may return 56789 which is not expected, it should always return NULL.  Fix
it by put ma_set_meta() before rcu_assign_pointer().

Link: https://lkml.kernel.org/r/20230314124203.91572-4-zhangpeng.00@bytedance.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: fix get wrong data_end in mtree_lookup_walk()

if (likely(offset > end))
max = pivots[offset];

The above code should be changed to if (likely(offset < end)), which is
correct. This affects the correctness of ma_data_end(). Now it seems
that the final result will not be wrong, but it is best to change it.
This patch does not change the code as above, because it simplifies the
code by the way.

Link: https://lkml.kernel.org/r/20230314124203.91572-1-zhangpeng.00@bytedance.com
Link: https://lkml.kernel.org/r/20230314124203.91572-2-zhangpeng.00@bytedance.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/swap: fix swap_info_struct race between swapoff and get_swap_pages()

The si->lock must be held when deleting the si from the available list.
Otherwise, another thread can re-add the si to the available list, which
can lead to memory corruption.  The only place we have found where this
happens is in the swapoff path.  This case can be described as below:

core 0                       core 1
swapoff

del_from_avail_list(si)      waiting

try lock si->lock            acquire swap_avail_lock
                             and re-add si into
                             swap_avail_head

acquire si->lock but missing si already being added again, and continuing
to clear SWP_WRITEOK, etc.

It can be easily found that a massive warning messages can be triggered
inside get_swap_pages() by some special cases, for example, we call
madvise(MADV_PAGEOUT) on blocks of touched memory concurrently, meanwhile,
run much swapon-swapoff operations (e.g.  stress-ng-swap).

However, in the worst case, panic can be caused by the above scene.  In
swapoff(), the memory used by si could be kept in swap_info[] after
turning off a swap.  This means memory corruption will not be caused
immediately until allocated and reset for a new swap in the swapon path.
A panic message caused: (with CONFIG_PLIST_DEBUG enabled)

------------[ cut here ]------------
top: 00000000e58a3003, n: 0000000013e75cda, p: 000000008cd4451a
prev: 0000000035b1e58a, n: 000000008cd4451a, p: 000000002150ee8d
next: 000000008cd4451a, n: 000000008cd4451a, p: 000000008cd4451a
WARNING: CPU: 21 PID: 1843 at lib/plist.c:60 plist_check_prev_next_node+0x50/0x70
Modules linked in: rfkill(E) crct10dif_ce(E)...
CPU: 21 PID: 1843 Comm: stress-ng Kdump: ... 5.10.134+
Hardware name: Alibaba Cloud ECS, BIOS 0.0.0 02/06/2015
pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
pc : plist_check_prev_next_node+0x50/0x70
lr : plist_check_prev_next_node+0x50/0x70
sp : ffff0018009d3c30
x29: ffff0018009d3c40 x28: ffff800011b32a98
x27: 0000000000000000 x26: ffff001803908000
x25: ffff8000128ea088 x24: ffff800011b32a48
x23: 0000000000000028 x22: ffff001800875c00
x21: ffff800010f9e520 x20: ffff001800875c00
x19: ffff001800fdc6e0 x18: 0000000000000030
x17: 0000000000000000 x16: 0000000000000000
x15: 0736076307640766 x14: 0730073007380731
x13: 0736076307640766 x12: 0730073007380731
x11: 000000000004058d x10: 0000000085a85b76
x9 : ffff8000101436e4 x8 : ffff800011c8ce08
x7 : 0000000000000000 x6 : 0000000000000001
x5 : ffff0017df9ed338 x4 : 0000000000000001
x3 : ffff8017ce62a000 x2 : ffff0017df9ed340
x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
plist_check_prev_next_node+0x50/0x70
plist_check_head+0x80/0xf0
plist_add+0x28/0x140
add_to_avail_list+0x9c/0xf0
_enable_swap_info+0x78/0xb4
__do_sys_swapon+0x918/0xa10
__arm64_sys_swapon+0x20/0x30
el0_svc_common+0x8c/0x220
do_el0_svc+0x2c/0x90
el0_svc+0x1c/0x30
el0_sync_handler+0xa8/0xb0
el0_sync+0x148/0x180
irq event stamp: 2082270

Now, si->lock locked before calling 'del_from_avail_list()' to make sure
other thread see the si had been deleted and SWP_WRITEOK cleared together,
will not reinsert again.

This problem exists in versions after stable 5.10.y.

Link: https://lkml.kernel.org/r/20230404154716.23058-1-rongwei.wang@linux.alibaba.com
Fixes: a2468cc9bfdff ("swap: choose swap device according to numa node")
Tested-by: Yongchen Yin <wb-yyc939293@alibaba-inc.com>
Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Aaron Lu <aaron.lu@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: fix sysfs interface lifetime

The current nilfs2 sysfs support has issues with the timing of creation
and deletion of sysfs entries, potentially leading to null pointer
dereferences, use-after-free, and lockdep warnings.

Some of the sysfs attributes for nilfs2 per-filesystem instance refer to
metadata file "cpfile", "sufile", or "dat", but
nilfs_sysfs_create_device_group that creates those attributes is executed
before the inodes for these metadata files are loaded, and
nilfs_sysfs_delete_device_group which deletes these sysfs entries is
called after releasing their metadata file inodes.

Therefore, access to some of these sysfs attributes may occur outside of
the lifetime of these metadata files, resulting in inode NULL pointer
dereferences or use-after-free.

In addition, the call to nilfs_sysfs_create_device_group() is made during
the locking period of the semaphore "ns_sem" of nilfs object, so the
shrinker call caused by the memory allocation for the sysfs entries, may
derive lock dependencies "ns_sem" -> (shrinker) -> "locks acquired in
nilfs_evict_inode()".

Since nilfs2 may acquire "ns_sem" deep in the call stack holding other
locks via its error handler __nilfs_error(), this causes lockdep to report
circular locking. This is a false positive and no circular locking
actually occurs as no inodes exist yet when
nilfs_sysfs_create_device_group() is called. Fortunately, the lockdep
warnings can be resolved by simply moving the call to
nilfs_sysfs_create_device_group() out of "ns_sem".

This fixes these sysfs issues by revising where the device's sysfs
interface is created/deleted and keeping its lifetime within the lifetime
of the metadata files above.

Link: https://lkml.kernel.org/r/20230330205515.6167-1-konishi.ryusuke@gmail.com
Fixes: dd70edbde262 ("nilfs2: integrate sysfs support into driver")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+979fa7f9c0d086fdc282@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/0000000000003414b505f7885f7e@google.com
Reported-by: syzbot+5b7d542076d9bddc3c6a@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/0000000000006ac86605f5f44eb9@google.com
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: take a page reference when removing device exclusive entries

Device exclusive page table entries are used to prevent CPU access to a
page whilst it is being accessed from a device.  Typically this is used to
implement atomic operations when the underlying bus does not support
atomic access.  When a CPU thread encounters a device exclusive entry it
locks the page and restores the original entry after calling mmu notifiers
to signal drivers that exclusive access is no longer available.

The device exclusive entry holds a reference to the page making it safe to
access the struct page whilst the entry is present.  However the fault
handling code does not hold the PTL when taking the page lock.  This means
if there are multiple threads faulting concurrently on the device
exclusive entry one will remove the entry whilst others will wait on the
page lock without holding a reference.

This can lead to threads locking or waiting on a folio with a zero
refcount.  Whilst mmap_lock prevents the pages getting freed via munmap()
they may still be freed by a migration.  This leads to warnings such as
PAGE_FLAGS_CHECK_AT_FREE due to the page being locked when the refcount
drops to zero.

Fix this by trying to take a reference on the folio before locking it.
The code already checks the PTE under the PTL and aborts if the entry is
no longer there.  It is also possible the folio has been unmapped, freed
and re-allocated allowing a reference to be taken on an unrelated folio.
This case is also detected by the PTE check and the folio is unlocked
without further changes.

Link: https://lkml.kernel.org/r/20230330012519.804116-1-apopple@nvidia.com
Fixes: b756a3b5e7ea ("mm: device exclusive memory access")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: vmalloc: avoid warn_alloc noise caused by fatal signal

There're some suspicious warn_alloc on my test serer, for example,

[13366.518837] warn_alloc: 81 callbacks suppressed
[13366.518841] test_verifier: vmalloc error: size 4096, page order 0, failed to allocate pages, mode:0x500dc2(GFP_HIGHUSER|__GFP_ZERO|__GFP_ACCOUNT), nodemask=(null),cpuset=/,mems_allowed=0-1
[13366.522240] CPU: 30 PID: 722463 Comm: test_verifier Kdump: loaded Tainted: G        W  O       6.2.0+ #638
[13366.524216] Call Trace:
[13366.524702]  <TASK>
[13366.525148]  dump_stack_lvl+0x6c/0x80
[13366.525712]  dump_stack+0x10/0x20
[13366.526239]  warn_alloc+0x119/0x190
[13366.526783]  ? alloc_pages_bulk_array_mempolicy+0x9e/0x2a0
[13366.527470]  __vmalloc_area_node+0x546/0x5b0
[13366.528066]  __vmalloc_node_range+0xc2/0x210
[13366.528660]  __vmalloc_node+0x42/0x50
[13366.529186]  ? bpf_prog_realloc+0x53/0xc0
[13366.529743]  __vmalloc+0x1e/0x30
[13366.530235]  bpf_prog_realloc+0x53/0xc0
[13366.530771]  bpf_patch_insn_single+0x80/0x1b0
[13366.531351]  bpf_jit_blind_constants+0xe9/0x1c0
[13366.531932]  ? __free_pages+0xee/0x100
[13366.532457]  ? free_large_kmalloc+0x58/0xb0
[13366.533002]  bpf_int_jit_compile+0x8c/0x5e0
[13366.533546]  bpf_prog_select_runtime+0xb4/0x100
[13366.534108]  bpf_prog_load+0x6b1/0xa50
[13366.534610]  ? perf_event_task_tick+0x96/0xb0
[13366.535151]  ? security_capable+0x3a/0x60
[13366.535663]  __sys_bpf+0xb38/0x2190
[13366.536120]  ? kvm_clock_get_cycles+0x9/0x10
[13366.536643]  __x64_sys_bpf+0x1c/0x30
[13366.537094]  do_syscall_64+0x38/0x90
[13366.537554]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
[13366.538107] RIP: 0033:0x7f78310f8e29
[13366.538561] Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 17 e0 2c 00 f7 d8 64 89 01 48
[13366.540286] RSP: 002b:00007ffe2a61fff8 EFLAGS: 00000206 ORIG_RAX: 0000000000000141
[13366.541031] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f78310f8e29
[13366.541749] RDX: 0000000000000080 RSI: 00007ffe2a6200b0 RDI: 0000000000000005
[13366.542470] RBP: 00007ffe2a620010 R08: 00007ffe2a6202a0 R09: 00007ffe2a6200b0
[13366.543183] R10: 00000000000f423e R11: 0000000000000206 R12: 0000000000407800
[13366.543900] R13: 00007ffe2a620540 R14: 0000000000000000 R15: 0000000000000000
[13366.544623]  </TASK>
[13366.545260] Mem-Info:
[13366.546121] active_anon:81319 inactive_anon:20733 isolated_anon:0
active_file:69450 inactive_file:5624 isolated_file:0
unevictable:0 dirty:10 writeback:0
slab_reclaimable:69649 slab_unreclaimable:48930
mapped:27400 shmem:12868 pagetables:4929
sec_pagetables:0 bounce:0
kernel_misc_reclaimable:0
free:15870308 free_pcp:142935 free_cma:0
[13366.551886] Node 0 active_anon:224836kB inactive_anon:33528kB active_file:175692kB inactive_file:13752kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:59248kB dirty:32kB writeback:0kB shmem:18252kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:4616kB pagetables:10664kB sec_pagetables:0kB all_unreclaimable? no
[13366.555184] Node 1 active_anon:100440kB inactive_anon:49404kB active_file:102108kB inactive_file:8744kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:50352kB dirty:8kB writeback:0kB shmem:33220kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB kernel_stack:3896kB pagetables:9052kB sec_pagetables:0kB all_unreclaimable? no
[13366.558262] Node 0 DMA free:15360kB boost:0kB min:304kB low:380kB high:456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[13366.560821] lowmem_reserve[]: 0 2735 31873 31873 31873
[13366.561981] Node 0 DMA32 free:2790904kB boost:0kB min:56028kB low:70032kB high:84036kB reserved_highatomic:0KB active_anon:1936kB inactive_anon:20kB active_file:396kB inactive_file:344kB unevictable:0kB writepending:0kB present:3129200kB managed:2801520kB mlocked:0kB bounce:0kB free_pcp:5188kB local_pcp:0kB free_cma:0kB
[13366.565148] lowmem_reserve[]: 0 0 29137 29137 29137
[13366.566168] Node 0 Normal free:28533824kB boost:0kB min:596740kB low:745924kB high:895108kB reserved_highatomic:28672KB active_anon:222900kB inactive_anon:33508kB active_file:175296kB inactive_file:13408kB unevictable:0kB writepending:32kB present:30408704kB managed:29837172kB mlocked:0kB bounce:0kB free_pcp:295724kB local_pcp:0kB free_cma:0kB
[13366.569485] lowmem_reserve[]: 0 0 0 0 0
[13366.570416] Node 1 Normal free:32141144kB boost:0kB min:660504kB low:825628kB high:990752kB reserved_highatomic:69632KB active_anon:100440kB inactive_anon:49404kB active_file:102108kB inactive_file:8744kB unevictable:0kB writepending:8kB present:33554432kB managed:33025372kB mlocked:0kB bounce:0kB free_pcp:270880kB local_pcp:46860kB free_cma:0kB
[13366.573403] lowmem_reserve[]: 0 0 0 0 0
[13366.574015] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15360kB
[13366.575474] Node 0 DMA32: 782*4kB (UME) 756*8kB (UME) 736*16kB (UME) 745*32kB (UME) 694*64kB (UME) 653*128kB (UME) 595*256kB (UME) 552*512kB (UME) 454*1024kB (UME) 347*2048kB (UME) 246*4096kB (UME) = 2790904kB
[13366.577442] Node 0 Normal: 33856*4kB (UMEH) 51815*8kB (UMEH) 42418*16kB (UMEH) 36272*32kB (UMEH) 22195*64kB (UMEH) 10296*128kB (UMEH) 7238*256kB (UMEH) 5638*512kB (UEH) 5337*1024kB (UMEH) 3506*2048kB (UMEH) 1470*4096kB (UME) = 28533784kB
[13366.580460] Node 1 Normal: 15776*4kB (UMEH) 37485*8kB (UMEH) 29509*16kB (UMEH) 21420*32kB (UMEH) 14818*64kB (UMEH) 13051*128kB (UMEH) 9918*256kB (UMEH) 7374*512kB (UMEH) 5397*1024kB (UMEH) 3887*2048kB (UMEH) 2002*4096kB (UME) = 32141240kB
[13366.583027] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
[13366.584380] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[13366.585702] Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
[13366.587042] Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[13366.588372] 87386 total pagecache pages
[13366.589266] 0 pages in swap cache
[13366.590327] Free swap  = 0kB
[13366.591227] Total swap = 0kB
[13366.592142] 16777082 pages RAM
[13366.593057] 0 pages HighMem/MovableOnly
[13366.594037] 357226 pages reserved
[13366.594979] 0 pages hwpoisoned

This failure really confuse me as there're still lots of available pages.
Finally I figured out it was caused by a fatal signal.  When a process is
allocating memory via vm_area_alloc_pages(), it will break directly even
if it hasn't allocated the requested pages when it receives a fatal
signal.  In that case, we shouldn't show this warn_alloc, as it is
useless.  We only need to show this warning when there're really no enough
pages.

Link: https://lkml.kernel.org/r/20230330162625.13604-1-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: initialize "struct nilfs_binfo_dat"->bi_pad field

nilfs_btree_assign_p() and nilfs_direct_assign_p() are not initializing
"struct nilfs_binfo_dat"->bi_pad field, causing uninit-value reports when
being passed to CRC function.

Link: https://lkml.kernel.org/r/20230326152146.15872-1-konishi.ryusuke@gmail.com
Reported-by: syzbot <syzbot+048585f3f4227bb2b49b@syzkaller.appspotmail.com>
Link: https://syzkaller.appspot.com/bug?extid=048585f3f4227bb2b49b
Reported-by: Dipanjan Das <mail.dipanjan.das@gmail.com>
Link: https://lkml.kernel.org/r/CANX2M5bVbzRi6zH3PTcNE_31TzerstOXUa9Bay4E6y6dX23_pg@mail.gmail.com
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

nilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread()

The finalization of nilfs_segctor_thread() can race with
nilfs_segctor_kill_thread() which terminates that thread, potentially
causing a use-after-free BUG as KASAN detected.

At the end of nilfs_segctor_thread(), it assigns NULL to "sc_task" member
of "struct nilfs_sc_info" to indicate the thread has finished, and then
notifies nilfs_segctor_kill_thread() of this using waitqueue
"sc_wait_task" on the struct nilfs_sc_info.

However, here, immediately after the NULL assignment to "sc_task", it is
possible that nilfs_segctor_kill_thread() will detect it and return to
continue the deallocation, freeing the nilfs_sc_info structure before the
thread does the notification.

This fixes the issue by protecting the NULL assignment to "sc_task" and
its notification, with spinlock "sc_state_lock" of the struct
nilfs_sc_info. Since nilfs_segctor_kill_thread() does a final check to
see if "sc_task" is NULL with "sc_state_lock" locked, this can eliminate
the race.

Link: https://lkml.kernel.org/r/20230327175318.8060-1-konishi.ryusuke@gmail.com
Reported-by: syzbot+b08ebcc22f8f3e6be43a@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/00000000000000660d05f7dfa877@google.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zsmalloc: document freeable stats

When freeable class stat was added to classes file (back in 2016) we
forgot to update zsmalloc documentation. Fix that.

Link: https://lkml.kernel.org/r/20230325024631.2817153-3-senozhatsky@chromium.org
Fixes: 1120ed548394 ("mm/zsmalloc: add `freeable' column to pool stat")
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

zsmalloc: document new fullness grouping

Patch series "zsmalloc: minor documentation updates".

Two minor patches that bring zsmalloc documentation up to date.

This patch (of 2):

Update documentation and reflect new zspages fullness grouping (we don't
use almost_empty and almost_full anymore).

Link: https://lkml.kernel.org/r/20230325024631.2817153-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20230325024631.2817153-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Fixes: 67e157eb3639 ("zsmalloc: show per fullness group class stats")
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fsdax: force clear dirty mark if CoW

XFS allows CoW on non-shared extents to combat fragmentation[1].  The old
non-shared extent could be mwrited before, its dax entry is marked dirty.

This results in a WARNing:

[   28.512349] ------------[ cut here ]------------
[   28.512622] WARNING: CPU: 2 PID: 5255 at fs/dax.c:390 dax_insert_entry+0x342/0x390
[   28.513050] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 nfs lockd grace fscache netfs nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables
[   28.515462] CPU: 2 PID: 5255 Comm: fsstress Kdump: loaded Not tainted 6.3.0-rc1-00001-g85e1481e19c1-dirty #117
[   28.515902] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Arch Linux 1.16.1-1-1 04/01/2014
[   28.516307] RIP: 0010:dax_insert_entry+0x342/0x390
[   28.516536] Code: 30 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc 48 8b 45 20 48 83 c0 01 e9 e2 fe ff ff 48 8b 45 20 48 83 c0 01 e9 cd fe ff ff <0f> 0b e9 53 ff ff ff 48 8b 7c 24 08 31 f6 e8 1b 61 a1 00 eb 8c 48
[   28.517417] RSP: 0000:ffffc9000845fb18 EFLAGS: 00010086
[   28.517721] RAX: 0000000000000053 RBX: 0000000000000155 RCX: 000000000018824b
[   28.518113] RDX: 0000000000000000 RSI: ffffffff827525a6 RDI: 00000000ffffffff
[   28.518515] RBP: ffffea00062092c0 R08: 0000000000000000 R09: ffffc9000845f9c8
[   28.518905] R10: 0000000000000003 R11: ffffffff82ddb7e8 R12: 0000000000000155
[   28.519301] R13: 0000000000000000 R14: 000000000018824b R15: ffff88810cfa76b8
[   28.519703] FS:  00007f14a0c94740(0000) GS:ffff88817bd00000(0000) knlGS:0000000000000000
[   28.520148] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   28.520472] CR2: 00007f14a0c8d000 CR3: 000000010321c004 CR4: 0000000000770ee0
[   28.520863] PKRU: 55555554
[   28.521043] Call Trace:
[   28.521219]  <TASK>
[   28.521368]  dax_fault_iter+0x196/0x390
[   28.521595]  dax_iomap_pte_fault+0x19b/0x3d0
[   28.521852]  __xfs_filemap_fault+0x234/0x2b0
[   28.522116]  __do_fault+0x30/0x130
[   28.522334]  do_fault+0x193/0x340
[   28.522586]  __handle_mm_fault+0x2d3/0x690
[   28.522975]  handle_mm_fault+0xe6/0x2c0
[   28.523259]  do_user_addr_fault+0x1bc/0x6f0
[   28.523521]  exc_page_fault+0x60/0x140
[   28.523763]  asm_exc_page_fault+0x22/0x30
[   28.524001] RIP: 0033:0x7f14a0b589ca
[   28.524225] Code: c5 fe 7f 07 c5 fe 7f 47 20 c5 fe 7f 47 40 c5 fe 7f 47 60 c5 f8 77 c3 66 0f 1f 84 00 00 00 00 00 40 0f b6 c6 48 89 d1 48 89 fa <f3> aa 48 89 d0 c5 f8 77 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90
[   28.525198] RSP: 002b:00007fff1dea1c98 EFLAGS: 00010202
[   28.525505] RAX: 000000000000001e RBX: 000000000014a000 RCX: 0000000000006046
[   28.525895] RDX: 00007f14a0c82000 RSI: 000000000000001e RDI: 00007f14a0c8d000
[   28.526290] RBP: 000000000000006f R08: 0000000000000004 R09: 000000000014a000
[   28.526681] R10: 0000000000000008 R11: 0000000000000246 R12: 028f5c28f5c28f5c
[   28.527067] R13: 8f5c28f5c28f5c29 R14: 0000000000011046 R15: 00007f14a0c946c0
[   28.527449]  </TASK>
[   28.527600] ---[ end trace 0000000000000000 ]---

To be able to delete this entry, clear its dirty mark before
invalidate_inode_pages2_range().

[1] https://lore.kernel.org/linux-xfs/20230321151339.GA11376@frogsfrogsfrogs/

Link: https://lkml.kernel.org/r/1679653680-2-1-git-send-email-ruansy.fnst@fujitsu.com
Fixes: f80e1668888f3 ("fsdax: invalidate pages when CoW")
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/hugetlb: fix uffd wr-protection for CoW optimization path

This patch fixes an issue that a hugetlb uffd-wr-protected mapping can be
writable even with uffd-wp bit set.  It only happens with hugetlb private
mappings, when someone firstly wr-protects a missing pte (which will
install a pte marker), then a write to the same page without any prior
access to the page.

Userfaultfd-wp trap for hugetlb was implemented in hugetlb_fault() before
reaching hugetlb_wp() to avoid taking more locks that userfault won't
need.  However there's one CoW optimization path that can trigger
hugetlb_wp() inside hugetlb_no_page(), which will bypass the trap.

This patch skips hugetlb_wp() for CoW and retries the fault if uffd-wp bit
is detected.  The new path will only trigger in the CoW optimization path
because generic hugetlb_fault() (e.g.  when a present pte was
wr-protected) will resolve the uffd-wp bit already.  Also make sure
anonymous UNSHARE won't be affected and can still be resolved, IOW only
skip CoW not CoR.

This patch will be needed for v5.19+ hence copy stable.

[peterx@redhat.com: v2]
Link: https://lkml.kernel.org/r/ZBzOqwF2wrHgBVZb@x1n
[peterx@redhat.com: v3]
Link: https://lkml.kernel.org/r/20230324142620.2344140-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20230321191840.1897940-1-peterx@redhat.com
Fixes: 166f3ecc0daf ("mm/hugetlb: hook page faults for uffd write protection")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: enable maple tree RCU mode by default

Use the maple tree in RCU mode for VMA tracking.

The maple tree tracks the stack and is able to update the pivot
(lower/upper boundary) in-place to allow the page fault handler to write
to the tree while holding just the mmap read lock.  This is safe as the
writes to the stack have a guard VMA which ensures there will always be a
NULL in the direction of the growth and thus will only update a pivot.

It is possible, but not recommended, to have VMAs that grow up/down
without guard VMAs.  syzbot has constructed a testcase which sets up a VMA
to grow and consume the empty space.  Overwriting the entire NULL entry
causes the tree to be altered in a way that is not safe for concurrent
readers; the readers may see a node being rewritten or one that does not
match the maple state they are using.

Enabling RCU mode allows the concurrent readers to see a stable node and
will return the expected result.

[Liam.Howlett@Oracle.com: we don't need to free the nodes with RCU[
Link: https://lore.kernel.org/linux-mm/000000000000b0a65805f663ace6@google.com/
Link: https://lkml.kernel.org/r/20230227173632.3292573-9-surenb@google.com
Fixes: d4af56c5c7c6 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: syzbot+8d95422d3537159ca390@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: add RCU lock checking to rcu callback functions

Dereferencing RCU objects within the RCU callback without the RCU check
has caused lockdep to complain.  Fix the RCU dereferencing by using the
RCU callback lock to ensure the operation is safe.

Also stop creating a new lock to use for dereferencing during destruction
of the tree or subtree.  Instead, pass through a pointer to the tree that
has the lock that is held for RCU dereferencing checking.  It also does
not make sense to use the maple state in the freeing scenario as the tree
walk is a special case where the tree no longer has the normal encodings
and parent pointers.

Link: https://lkml.kernel.org/r/20230227173632.3292573-8-surenb@google.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: add smp_rmb() to dead node detection

Add an smp_rmb() before reading the parent pointer to ensure that anything
read from the node prior to the parent pointer hasn't been reordered ahead
of this check.

The is necessary for RCU mode.

Link: https://lkml.kernel.org/r/20230227173632.3292573-7-surenb@google.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

maple_tree: fix write memory barrier of nodes once dead for RCU mode

During the development of the maple tree, the strategy of freeing multiple
nodes changed and, in the process, the pivots were reused to store
pointers to dead nodes. To ensure the readers see accurate pivots, the
writers need to mark the nodes as dead and call smp_wmb() to ensure any
readers can identify the node as dead before using the pivot values.

There were two places where the old method of marking the node as dead
without smp_wmb() were being used, which resulted in RCU readers seeing
the wrong pivot value before seeing the node was dead. Fix this race
condition by using mte_set_node_dead() which has the smp_wmb() call to
ensure the race is closed.

Add a WARN_ON() to the ma_free_rcu() call to ensure all nodes being freed
are marked as dead to ensure there are no other call paths besides the two
updated paths.

This is necessary for the RCU mode of the maple tree.

Link: https://lkml.kernel.org/r/20230227173632.3292573-6-surenb@google.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>