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

bpf, arm: Fix various typos in comments

Various spelling mistakes in comments. Detected with the help of
Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220318103729.157574-9-Julia.Lawall@inria.fr

libbpf: Close fd in bpf_object__reuse_map

pin_fd is dup-ed and assigned in bpf_map__reuse_fd. Close it
in bpf_object__reuse_map after reuse.

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220319030533.3132250-1-hengqi.chen@gmail.com

bpftool: Fix print error when show bpf map

If there is no btf_id or frozen, it will not show the pids, but the pids don't
depend on any one of them.

Below is the result after this change:

  $ ./bpftool map show
  2: lpm_trie  flags 0x1
key 8B  value 8B  max_entries 1  memlock 4096B
pids systemd(1)
  3: lpm_trie  flags 0x1
key 20B  value 8B  max_entries 1  memlock 4096B
pids systemd(1)

While before this change, the 'pids systemd(1)' can't be displayed.

Fixes: 9330986c0300 ("bpf: Add bloom filter map implementation")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220320060815.7716-1-laoar.shao@gmail.com

bpf: Fix kprobe_multi return probe backtrace

Andrii reported that backtraces from kprobe_multi program attached
as return probes are not complete and showing just initial entry [1].

It's caused by changing registers to have original function ip address
as instruction pointer even for return probe, which will screw backtrace
from return probe.

This change keeps registers intact and store original entry ip and
link address on the stack in bpf_kprobe_multi_run_ctx struct, where
bpf_get_func_ip and bpf_get_attach_cookie helpers for kprobe_multi
programs can find it.

[1] https://lore.kernel.org/bpf/CAEf4BzZDDqK24rSKwXNp7XL3ErGD4bZa1M6c_c4EvDSt3jrZcg@mail.gmail.com/T/#m8d1301c0ea0892ddf9dc6fba57a57b8cf11b8c51

Fixes: ca74823c6e16 ("bpf: Add cookie support to programs attached with kprobe multi link")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220321070113.1449167-3-jolsa@kernel.org

Revert "bpf: Add support to inline bpf_get_func_ip helper on x86"

This reverts commit 97ee4d20ee67eb462581a7af01442de6586e390b.

Following change is adding more complexity to bpf_get_func_ip
helper for kprobe_multi programs, which can't be inlined easily.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220321070113.1449167-2-jolsa@kernel.org

bpf: Simplify check in btf_parse_hdr()

Replace offsetof(hdr_len) + sizeof(hdr_len) with offsetofend(hdr_len) to
simplify the check for correctness of btf_data_size in btf_parse_hdr()

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220320075240.1001728-1-ytcoode@gmail.com

selftests/bpf/test_lirc_mode2.sh: Exit with proper code

When test_lirc_mode2_user exec failed, the test report failed but still
exit with 0. Fix it by exiting with an error code.

Another issue is for the LIRCDEV checking. With bash -n, we need to quote
the variable, or it will always be true. So if test_lirc_mode2_user was
not run, just exit with skip code.

Fixes: 6bdd533cee9a ("bpf: add selftest for lirc_mode2 type program")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220321024149.157861-1-liuhangbin@gmail.com

bpf: Check for NULL return from bpf_get_btf_vmlinux

When CONFIG_DEBUG_INFO_BTF is disabled, bpf_get_btf_vmlinux can return a
NULL pointer. Check for it in btf_get_module_btf to prevent a NULL pointer
dereference.

While kernel test robot only complained about this specific case, let's
also check for NULL in other call sites of bpf_get_btf_vmlinux.

Fixes: 9492450fd287 ("bpf: Always raise reference in btf_get_module_btf")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220320143003.589540-1-memxor@gmail.com

selftests/bpf: Test skipping stacktrace

Add a test case for stacktrace with skip > 0 using a small sized
buffer. It didn't support skipping entries greater than or equal to
the size of buffer and filled the skipped part with 0.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220314182042.71025-2-namhyung@kernel.org

bpf: Adjust BPF stack helper functions to accommodate skip > 0

Let's say that the caller has storage for num_elem stack frames.  Then,
the BPF stack helper functions walk the stack for only num_elem frames.
This means that if skip > 0, one keeps only 'num_elem - skip' frames.

This is because it sets init_nr in the perf_callchain_entry to the end
of the buffer to save num_elem entries only.  I believe it was because
the perf callchain code unwound the stack frames until it reached the
global max size (sysctl_perf_event_max_stack).

However it now has perf_callchain_entry_ctx.max_stack to limit the
iteration locally.  This simplifies the code to handle init_nr in the
BPF callstack entries and removes the confusion with the perf_event's
__PERF_SAMPLE_CALLCHAIN_EARLY which sets init_nr to 0.

Also change the comment on bpf_get_stack() in the header file to be
more explicit what the return value means.

Fixes: c195651e565a ("bpf: add bpf_get_stack helper")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/30a7b5d5-6726-1cc2-eaee-8da2828a9a9c@oracle.com
Link: https://lore.kernel.org/bpf/20220314182042.71025-1-namhyung@kernel.org
Based-on-patch-by: Eugene Loh <eugene.loh@oracle.com>

bpf: Select proper size for bpf_prog_pack

Using HPAGE_PMD_SIZE as the size for bpf_prog_pack is not ideal in some
cases. Specifically, for NUMA systems, __vmalloc_node_range requires
PMD_SIZE * num_online_nodes() to allocate huge pages. Also, if the system
does not support huge pages (i.e., with cmdline option nohugevmalloc), it
is better to use PAGE_SIZE packs.

Add logic to select proper size for bpf_prog_pack. This solution is not
ideal, as it makes assumption about the behavior of module_alloc and
__vmalloc_node_range. However, it appears to be the easiest solution as
it doesn't require changes in module_alloc and vmalloc code.

Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator")
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220311201135.3573610-1-song@kernel.org

Merge branch 'Make 2-byte access to bpf_sk_lookup->remote_port endian-agnostic'

Jakub Sitnicki says:

====================

This patch set is a result of a discussion we had around the RFC patchset from
Ilya [1]. The fix for the narrow loads from the RFC series is still relevant,
but this series does not depend on it. Nor is it required to unbreak sk_lookup
tests on BE, if this series gets applied.

To summarize the takeaways from [1]:

1) we want to make 2-byte load from ctx->remote_port portable across LE and BE,
2) we keep the 4-byte load from ctx->remote_port as it is today - result varies
on endianess of the platform.

[1] https://lore.kernel.org/bpf/20220222182559.2865596-2-iii@linux.ibm.com/

v1 -> v2:
- Remove needless check that 4-byte load is from &ctx->remote_port offset
(Martin)

[v1]: https://lore.kernel.org/bpf/20220317165826.1099418-1-jakub@cloudflare.com/
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Fix test for 4-byte load from remote_port on big-endian

The context access converter rewrites the 4-byte load from
bpf_sk_lookup->remote_port to a 2-byte load from bpf_sk_lookup_kern
structure.

It means that we cannot treat the destination register contents as a 32-bit
value, or the code will not be portable across big- and little-endian
architectures.

This is exactly the same case as with 4-byte loads from bpf_sock->dst_port
so follow the approach outlined in [1] and treat the register contents as a
16-bit value in the test.

[1]: https://lore.kernel.org/bpf/20220317113920.1068535-5-jakub@cloudflare.com/

Fixes: 2ed0dc5937d3 ("selftests/bpf: Cover 4-byte load from remote_port in bpf_sk_lookup")
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220319183356.233666-4-jakub@cloudflare.com

selftests/bpf: Fix u8 narrow load checks for bpf_sk_lookup remote_port

In commit 9a69e2b385f4 ("bpf: Make remote_port field in struct
bpf_sk_lookup 16-bit wide") ->remote_port field changed from __u32 to
__be16.

However, narrow load tests which exercise 1-byte sized loads from
offsetof(struct bpf_sk_lookup, remote_port) were not adopted to reflect the
change.

As a result, on little-endian we continue testing loads from addresses:

- (__u8 *)&ctx->remote_port + 3
- (__u8 *)&ctx->remote_port + 4

which map to the zero padding following the remote_port field, and don't
break the tests because there is no observable change.

While on big-endian, we observe breakage because tests expect to see zeros
for values loaded from:

- (__u8 *)&ctx->remote_port - 1
- (__u8 *)&ctx->remote_port - 2

Above addresses map to ->remote_ip6 field, which precedes ->remote_port,
and are populated during the bpf_sk_lookup IPv6 tests.

Unsurprisingly, on s390x we observe:

#136/38 sk_lookup/narrow access to ctx v4:OK
#136/39 sk_lookup/narrow access to ctx v6:FAIL

Fix it by removing the checks for 1-byte loads from offsets outside of the
->remote_port field.

Fixes: 9a69e2b385f4 ("bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide")
Suggested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220319183356.233666-3-jakub@cloudflare.com

bpf: Treat bpf_sk_lookup remote_port as a 2-byte field

In commit 9a69e2b385f4 ("bpf: Make remote_port field in struct
bpf_sk_lookup 16-bit wide") the remote_port field has been split up and
re-declared from u32 to be16.

However, the accompanying changes to the context access converter have not
been well thought through when it comes big-endian platforms.

Today 2-byte wide loads from offsetof(struct bpf_sk_lookup, remote_port)
are handled as narrow loads from a 4-byte wide field.

This by itself is not enough to create a problem, but when we combine

1. 32-bit wide access to ->remote_port backed by a 16-wide wide load, with
2. inherent difference between litte- and big-endian in how narrow loads
need have to be handled (see bpf_ctx_narrow_access_offset),

we get inconsistent results for a 2-byte loads from &ctx->remote_port on LE
and BE architectures. This in turn makes BPF C code for the common case of
2-byte load from ctx->remote_port not portable.

To rectify it, inform the context access converter that remote_port is
2-byte wide field, and only 1-byte loads need to be treated as narrow
loads.

At the same time, we special-case the 4-byte load from &ctx->remote_port to
continue handling it the same way as do today, in order to keep the
existing BPF programs working.

Fixes: 9a69e2b385f4 ("bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide")
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220319183356.233666-2-jakub@cloudflare.com

Merge branch 'Enable non-atomic allocations in local storage'

Joanne Koong says:

====================

From: Joanne Koong <joannelkoong@gmail.com>

Currently, local storage memory can only be allocated atomically
(GFP_ATOMIC). This restriction is too strict for sleepable bpf
programs.

In this patchset, sleepable programs can allocate memory in local
storage using GFP_KERNEL, while non-sleepable programs always default to
GFP_ATOMIC.

v3 <- v2:
* Add extra case to local_storage.c selftest to test associating multiple
elements with the local storage, which triggers a GFP_KERNEL allocation in
local_storage_update().
* Cast gfp_t to __s32 in verifier to fix the sparse warnings

v2 <- v1:
* Allocate the memory before/after the raw_spin_lock_irqsave, depending
on the gfp flags
* Rename mem_flags to gfp_flags
* Reword the comment "*mem_flags* is set by the bpf verifier" to
"*gfp_flags* is a hidden argument provided by the verifier"
* Add a sentence to the commit message about existing local storage
selftests covering both the GFP_ATOMIC and GFP_KERNEL paths in
bpf_local_storage_update.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Test for associating multiple elements with the local storage

This patch adds a few calls to the existing local storage selftest to
test that we can associate multiple elements with the local storage.

The sleepable program's call to bpf_sk_storage_get with sk_storage_map2
will lead to an allocation of a new selem under the GFP_KERNEL flag.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220318045553.3091807-3-joannekoong@fb.com

bpf: Enable non-atomic allocations in local storage

Currently, local storage memory can only be allocated atomically
(GFP_ATOMIC). This restriction is too strict for sleepable bpf
programs.

In this patch, the verifier detects whether the program is sleepable,
and passes the corresponding GFP_KERNEL or GFP_ATOMIC flag as a
5th argument to bpf_task/sk/inode_storage_get. This flag will propagate
down to the local storage functions that allocate memory.

Please note that bpf_task/sk/inode_storage_update_elem functions are
invoked by userspace applications through syscalls. Preemption is
disabled before bpf_task/sk/inode_storage_update_elem is called, which
means they will always have to allocate memory atomically.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220318045553.3091807-2-joannekoong@fb.com

libbpf: Avoid NULL deref when initializing map BTF info

If BPF object doesn't have an BTF info, don't attempt to search for BTF
types describing BPF map key or value layout.

Fixes: 262cfb74ffda ("libbpf: Init btf_{key,value}_type_id on internal map open")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220320001911.3640917-1-andrii@kernel.org

bpf: Always raise reference in btf_get_module_btf

Align it with helpers like bpf_find_btf_id, so all functions returning
BTF in out parameter follow the same rule of raising reference
consistently, regardless of module or vmlinux BTF.

Adjust existing callers to handle the change accordinly.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220317115957.3193097-10-memxor@gmail.com

bpf: Factor out fd returning from bpf_btf_find_by_name_kind

In next few patches, we need a helper that searches all kernel BTFs
(vmlinux and module BTFs), and finds the type denoted by 'name' and
'kind'. Turns out bpf_btf_find_by_name_kind already does the same thing,
but it instead returns a BTF ID and optionally fd (if module BTF). This
is used for relocating ksyms in BPF loader code (bpftool gen skel -L).

We extract the core code out into a new helper bpf_find_btf_id, which
returns the BTF ID in the return value, and BTF pointer in an out
parameter. The reference for the returned BTF pointer is always raised,
hence user must either transfer it (e.g. to a fd), or release it after
use.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220317115957.3193097-2-memxor@gmail.com

bpftool: Add BPF_TRACE_KPROBE_MULTI to attach type names table

BPF_TRACE_KPROBE_MULTI is a new attach type name, add it to bpftool's
table. This fixes a currently failing CI bpftool check.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220318150106.2933343-1-andrii@kernel.org

Merge branch 'bpf-fix-sock-field-tests'

Jakub Sitnicki says:

====================
I think we have reached a consensus [1] on how the test for the 4-byte load from
bpf_sock->dst_port and bpf_sk_lookup->remote_port should look, so here goes v3.

I will submit a separate set of patches for bpf_sk_lookup->remote_port tests.

This series has been tested on x86_64 and s390 on top of recent bpf-next -
ad13baf45691 ("selftests/bpf: Test subprog jit when toggle bpf_jit_harden
repeatedly").

[1] https://lore.kernel.org/bpf/87k0cwxkzs.fsf@cloudflare.com/

v2 -> v3:
- Split what was previously patch 2 which was doing two things
- Use BPF_TCP_* constants (Martin)
- Treat the result of 4-byte load from dst_port as a 16-bit value (Martin)
- Typo fixup and some rewording in patch 4 description
v1 -> v2:
- Limit read_sk_dst_port only to client traffic (patch 2)
- Make read_sk_dst_port pass on litte- and big-endian (patch 3)

v1: https://lore.kernel.org/bpf/20220225184130.483208-1-jakub@cloudflare.com/
v2: https://lore.kernel.org/bpf/20220227202757.519015-1-jakub@cloudflare.com/
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

selftests/bpf: Fix test for 4-byte load from dst_port on big-endian

The check for 4-byte load from dst_port offset into bpf_sock is failing on
big-endian architecture - s390. The bpf access converter rewrites the
4-byte load to a 2-byte load from sock_common at skc_dport offset, as shown
below.

  * s390 / llvm-objdump -S --no-show-raw-insn

  00000000000002a0 <sk_dst_port__load_word>:
        84:       r1 = *(u32 *)(r1 + 48)
        85:       w0 = 1
        86:       if w1 == 51966 goto +1 <LBB5_2>
        87:       w0 = 0
  00000000000002c0 <LBB5_2>:
        88:       exit

  * s390 / bpftool prog dump xlated

  _Bool sk_dst_port__load_word(struct bpf_sock * sk):
    35: (69) r1 = *(u16 *)(r1 +12)
    36: (bc) w1 = w1
    37: (b4) w0 = 1
    38: (16) if w1 == 0xcafe goto pc+1
    39: (b4) w0 = 0
    40: (95) exit

  * x86_64 / llvm-objdump -S --no-show-raw-insn

  00000000000002a0 <sk_dst_port__load_word>:
        84:       r1 = *(u32 *)(r1 + 48)
        85:       w0 = 1
        86:       if w1 == 65226 goto +1 <LBB5_2>
        87:       w0 = 0
  00000000000002c0 <LBB5_2>:
        88:       exit

  * x86_64 / bpftool prog dump xlated

  _Bool sk_dst_port__load_word(struct bpf_sock * sk):
    33: (69) r1 = *(u16 *)(r1 +12)
    34: (b4) w0 = 1
    35: (16) if w1 == 0xfeca goto pc+1
    36: (b4) w0 = 0
    37: (95) exit

This leads to surprises if we treat the destination register contents as a
32-bit value, ignoring the fact that in reality it contains a 16-bit value.

On little-endian the register contents reflect the bpf_sock struct
definition, where the lower 16-bits contain the port number:

struct bpf_sock {
...
__be16 dst_port; /* offset 48 */
__u16 :16;
...
};

However, on big-endian the register contents suggest that field the layout
of bpf_sock struct is as so:

struct bpf_sock {
...
__u16 :16; /* offset 48 */
__be16 dst_port;
...
};

Account for this quirky access conversion in the test case exercising the
4-byte load by treating the result as 16-bit wide.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220317113920.1068535-5-jakub@cloudflare.com

selftests/bpf: Use constants for socket states in sock_fields test

Replace magic numbers in BPF code with constants from bpf.h, so that they
don't require an explanation in the comments.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220317113920.1068535-4-jakub@cloudflare.com

selftests/bpf: Check dst_port only on the client socket

cgroup_skb/egress programs which sock_fields test installs process packets
flying in both directions, from the client to the server, and in reverse
direction.

Recently added dst_port check relies on the fact that destination
port (remote peer port) of the socket which sends the packet is known ahead
of time. This holds true only for the client socket, which connects to the
known server port.

Filter out any traffic that is not egressing from the client socket in the
BPF program that tests reading the dst_port.

Fixes: 8f50f16ff39d ("selftests/bpf: Extend verifier and bpf_sock tests for dst_port loads")
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220317113920.1068535-3-jakub@cloudflare.com

selftests/bpf: Fix error reporting from sock_fields programs

The helper macro that records an error in BPF programs that exercise sock
fields access has been inadvertently broken by adaptation work that
happened in commit b18c1f0aa477 ("bpf: selftest: Adapt sock_fields test to
use skel and global variables").

BPF_NOEXIST flag cannot be used to update BPF_MAP_TYPE_ARRAY. The operation
always fails with -EEXIST, which in turn means the error never gets
recorded, and the checks for errors always pass.

Revert the change in update flags.

Fixes: b18c1f0aa477 ("bpf: selftest: Adapt sock_fields test to use skel and global variables")
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220317113920.1068535-2-jakub@cloudflare.com

Merge branch 'Subskeleton support for BPF librariesThread-Topic: [PATCH bpf-next v4 0/5'

Delyan Kratunov says:

====================

In the quest for ever more modularity, a new need has arisen - the ability to
access data associated with a BPF library from a corresponding userspace library.
The catch is that we don't want the userspace library to know about the structure of the
final BPF object that the BPF library is linked into.

In pursuit of this modularity, this patch series introduces *subskeletons.*
Subskeletons are similar in use and design to skeletons with a couple of differences:

1. The generated storage types do not rely on contiguous storage for the library's
variables because they may be interspersed randomly throughout the final BPF object's sections.

2. Subskeletons do not own objects and instead require a loaded bpf_object* to
be passed at runtime in order to be initialized. By extension, symbols are resolved at
runtime by parsing the final object's BTF.

3. Subskeletons allow access to all global variables, programs, and custom maps. They also expose
the internal maps *of the final object*. This allows bpf_var_skeleton objects to contain a bpf_map**
instead of a section name.

Changes since v3:
- Re-add key/value type lookup for legacy user maps (fixing btf test)
- Minor cleanups (missed sanitize_identifier call, error messages, formatting)

Changes since v2:
- Reuse SEC_NAME strict mode flag
- Init bpf_map->btf_value_type_id on open for internal maps *and* user BTF maps
- Test custom section names (.data.foo) and overlapping kconfig externs between the final object and the library
- Minor review comments in gen.c & libbpf.c

Changes since v1:
- Introduced new strict mode knob for single-routine-in-.text compatibility behavior, which
   disproportionately affects library objects. bpftool works in 1.0 mode so subskeleton generation
   doesn't have to worry about this now.
- Made bpf_map_btf_value_type_id available earlier and used it wherever applicable.
- Refactoring in bpftool gen.c per review comments.
- Subskels now use typeof() for array and func proto globals to avoid the need for runtime split btf.
- Expanded the subskeleton test to include arrays, custom maps, extern maps, weak symbols, and kconfigs.
- selftests/bpf/Makefile now generates a subskel.h for every skel.h it would make.

For reference, here is a shortened subskeleton header:

#ifndef __TEST_SUBSKELETON_LIB_SUBSKEL_H__
#define __TEST_SUBSKELETON_LIB_SUBSKEL_H__

struct test_subskeleton_lib {
struct bpf_object *obj;
struct bpf_object_subskeleton *subskel;
struct {
struct bpf_map *map2;
struct bpf_map *map1;
struct bpf_map *data;
struct bpf_map *rodata;
struct bpf_map *bss;
struct bpf_map *kconfig;
} maps;
struct {
struct bpf_program *lib_perf_handler;
} progs;
struct test_subskeleton_lib__data {
int *var6;
int *var2;
int *var5;
} data;
struct test_subskeleton_lib__rodata {
int *var1;
} rodata;
struct test_subskeleton_lib__bss {
struct {
int var3_1;
__s64 var3_2;
} *var3;
int *libout1;
typeof(int[4]) *var4;
typeof(int (*)()) *fn_ptr;
} bss;
struct test_subskeleton_lib__kconfig {
_Bool *CONFIG_BPF_SYSCALL;
} kconfig;

static inline struct test_subskeleton_lib *
test_subskeleton_lib__open(const struct bpf_object *src)
{
struct test_subskeleton_lib *obj;
struct bpf_object_subskeleton *s;
int err;

...
s = (struct bpf_object_subskeleton *)calloc(1, sizeof(*s));
...

s->var_cnt = 9;
...

s->vars[0].name = "var6";
s->vars[0].map = &obj->maps.data;
s->vars[0].addr = (void**) &obj->data.var6;
  ...

/* maps */
...

/* programs */
s->prog_cnt = 1;
...

err = bpf_object__open_subskeleton(s);
  ...
return obj;
}
#endif /* __TEST_SUBSKELETON_LIB_SUBSKEL_H__ */
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

selftests/bpf: Test subskeleton functionality

This patch changes the selftests/bpf Makefile to also generate
a subskel.h for every skel.h it would have normally generated.

Separately, it also introduces a new subskeleton test which tests
library objects, externs, weak symbols, kconfigs, and user maps.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1bd24956940bbbfe169bb34f7f87b11df52ef011.1647473511.git.delyank@fb.com

bpftool: Add support for subskeletons

Subskeletons are headers which require an already loaded program to
operate.

For example, when a BPF library is linked into a larger BPF object file,
the library userspace needs a way to access its own global variables
without requiring knowledge about the larger program at build time.

As a result, subskeletons require a loaded bpf_object to open().
Further, they find their own symbols in the larger program by
walking BTF type data at run time.

At this time, programs, maps, and globals are supported through
non-owning pointers.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/ca8a48b4841c72d285ecce82371bef4a899756cb.1647473511.git.delyank@fb.com

libbpf: Add subskeleton scaffolding

In symmetry with bpf_object__open_skeleton(),
bpf_object__open_subskeleton() performs the actual walking and linking
of maps, progs, and globals described by bpf_*_skeleton objects.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/6942a46fbe20e7ebf970affcca307ba616985b15.1647473511.git.delyank@fb.com

libbpf: Init btf_{key,value}_type_id on internal map open

For internal and user maps, look up the key and value btf
types on open() and not load(), so that `bpf_map_btf_value_type_id`
is usable in `bpftool gen`.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/78dbe4e457b4a05e098fc6c8f50014b680c86e4e.1647473511.git.delyank@fb.com

libbpf: .text routines are subprograms in strict mode

Currently, libbpf considers a single routine in .text to be a program. This
is particularly confusing when it comes to library objects - a single routine
meant to be used as an extern will instead be considered a bpf_program.

This patch hides this compatibility behavior behind the pre-existing
SEC_NAME strict mode flag.

Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/018de8d0d67c04bf436055270d35d394ba393505.1647473511.git.delyank@fb.com

Merge branch 'bpf: Add kprobe multi link'

Jiri Olsa says:

====================

hi,
this patchset adds new link type BPF_TRACE_KPROBE_MULTI that attaches
kprobe program through fprobe API [1] instroduced by Masami.

The fprobe API allows to attach probe on multiple functions at once very
fast, because it works on top of ftrace. On the other hand this limits
the probe point to the function entry or return.

With bpftrace support I see following attach speed:

  # perf stat --null -r 5 ./src/bpftrace -e 'kprobe:x* { } i:ms:1 { exit(); } '
  Attaching 2 probes...
  Attaching 3342 functions
  ...

  1.4960 +- 0.0285 seconds time elapsed  ( +-  1.91% )

v3 changes:
  - based on latest fprobe post from Masami [2]
  - add acks
  - add extra comment to kprobe_multi_link_handler wrt entry ip setup [Masami]
  - keep swap_words_64 static and swap values directly in
    bpf_kprobe_multi_cookie_swap [Andrii]
  - rearrange locking/migrate setup in kprobe_multi_link_prog_run [Andrii]
  - move uapi fields [Andrii]
  - add bpf_program__attach_kprobe_multi_opts function [Andrii]
  - many small test changes [Andrii]
  - added tests for bpf_program__attach_kprobe_multi_opts
  - make kallsyms_lookup_name check for empty string [Andrii]

v2 changes:
  - based on latest fprobe changes [1]
  - renaming the uapi interface to kprobe multi
  - adding support for sort_r to pass user pointer for swap functions
    and using that in cookie support to keep just single functions array
  - moving new link to kernel/trace/bpf_trace.c file
  - using single fprobe callback function for entry and exit
  - using kvzalloc, libbpf_ensure_mem functions
  - adding new k[ret]probe.multi sections instead of using current kprobe
  - used glob_match from test_progs.c, added '?' matching
  - move bpf_get_func_ip verifier inline change to seprate change
  - couple of other minor fixes

Also available at:
  https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
  bpf/kprobe_multi

thanks,
jirka

[1] https://lore.kernel.org/bpf/164458044634.586276.3261555265565111183.stgit@devnote2/
[2] https://lore.kernel.org/bpf/164735281449.1084943.12438881786173547153.stgit@devnote2/
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Add cookie test for bpf_program__attach_kprobe_multi_opts

Adding bpf_cookie test for programs attached by
bpf_program__attach_kprobe_multi_opts API.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-14-jolsa@kernel.org

selftests/bpf: Add attach test for bpf_program__attach_kprobe_multi_opts

Adding tests for bpf_program__attach_kprobe_multi_opts function,
that test attach with pattern, symbols and addrs.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-13-jolsa@kernel.org

selftests/bpf: Add kprobe_multi bpf_cookie test

Adding bpf_cookie test for programs attached by kprobe_multi links.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-12-jolsa@kernel.org

selftests/bpf: Add kprobe_multi attach test

Adding kprobe_multi attach test that uses new fprobe interface to
attach kprobe program to multiple functions.

The test is attaching programs to bpf_fentry_test* functions and
uses single trampoline program bpf_prog_test_run to trigger
bpf_fentry_test* functions.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-11-jolsa@kernel.org

libbpf: Add bpf_program__attach_kprobe_multi_opts function

Adding bpf_program__attach_kprobe_multi_opts function for attaching
kprobe program to multiple functions.

  struct bpf_link *
  bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
                                        const char *pattern,
                                        const struct bpf_kprobe_multi_opts *opts);

User can specify functions to attach with 'pattern' argument that
allows wildcards (*?' supported) or provide symbols or addresses
directly through opts argument. These 3 options are mutually
exclusive.

When using symbols or addresses, user can also provide cookie value
for each symbol/address that can be retrieved later in bpf program
with bpf_get_attach_cookie helper.

  struct bpf_kprobe_multi_opts {
          size_t sz;
          const char **syms;
          const unsigned long *addrs;
          const __u64 *cookies;
          size_t cnt;
          bool retprobe;
          size_t :0;
  };

Symbols, addresses and cookies are provided through opts object
(syms/addrs/cookies) as array pointers with specified count (cnt).

Each cookie value is paired with provided function address or symbol
with the same array index.

The program can be also attached as return probe if 'retprobe' is set.

For quick usage with NULL opts argument, like:

  bpf_program__attach_kprobe_multi_opts(prog, "ksys_*", NULL)

the 'prog' will be attached as kprobe to 'ksys_*' functions.

Also adding new program sections for automatic attachment:

  kprobe.multi/<symbol_pattern>
  kretprobe.multi/<symbol_pattern>

The symbol_pattern is used as 'pattern' argument in
bpf_program__attach_kprobe_multi_opts function.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-10-jolsa@kernel.org

libbpf: Add bpf_link_create support for multi kprobes

Adding new kprobe_multi struct to bpf_link_create_opts object
to pass multiple kprobe data to link_create attr uapi.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-9-jolsa@kernel.org

libbpf: Add libbpf_kallsyms_parse function

Move the kallsyms parsing in internal libbpf_kallsyms_parse
function, so it can be used from other places.

It will be used in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-8-jolsa@kernel.org

bpf: Add cookie support to programs attached with kprobe multi link

Adding support to call bpf_get_attach_cookie helper from
kprobe programs attached with kprobe multi link.

The cookie is provided by array of u64 values, where each
value is paired with provided function address or symbol
with the same array index.

When cookie array is provided it's sorted together with
addresses (check bpf_kprobe_multi_cookie_swap). This way
we can find cookie based on the address in
bpf_get_attach_cookie helper.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-7-jolsa@kernel.org

bpf: Add support to inline bpf_get_func_ip helper on x86

Adding support to inline it on x86, because it's single
load instruction.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-6-jolsa@kernel.org

bpf: Add bpf_get_func_ip kprobe helper for multi kprobe link

Adding support to call bpf_get_func_ip helper from kprobe
programs attached by multi kprobe link.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-5-jolsa@kernel.org

Merge branch 'fprobe: Introduce fprobe function entry/exit probe'

Masami Hiramatsu says:

====================

Hi,

Here is the 12th version of fprobe. This version fixes a possible gcc-11 issue which
was reported as kretprobes on arm issue, and also I updated the fprobe document.

The previous version (v11) is here[1];

[1] https://lore.kernel.org/all/164701432038.268462.3329725152949938527.stgit@devnote2/T/#u

This series introduces the fprobe, the function entry/exit probe
with multiple probe point support for x86, arm64 and powerpc64le.
This also introduces the rethook for hooking function return as same as
the kretprobe does. This abstraction will help us to generalize the fgraph
tracer, because we can just switch to it from the rethook in fprobe,
depending on the kernel configuration.

The patch [1/12] is from Jiri's series[2].

[2] https://lore.kernel.org/all/20220104080943.113249-1-jolsa@kernel.org/T/#u

And the patch [9/10] adds the FPROBE_FL_KPROBE_SHARED flag for the case
if user wants to share the same code (or share a same resource) on the
fprobe and the kprobes.

I forcibly updated my kprobes/fprobe branch, you can pull this series
from:

https://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git kprobes/fprobe

Thank you,
---

Jiri Olsa (1):
ftrace: Add ftrace_set_filter_ips function
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

bpf: Add multi kprobe link

Adding new link type BPF_LINK_TYPE_KPROBE_MULTI that attaches kprobe
program through fprobe API.

The fprobe API allows to attach probe on multiple functions at once
very fast, because it works on top of ftrace. On the other hand this
limits the probe point to the function entry or return.

The kprobe program gets the same pt_regs input ctx as when it's attached
through the perf API.

Adding new attach type BPF_TRACE_KPROBE_MULTI that allows attachment
kprobe to multiple function with new link.

User provides array of addresses or symbols with count to attach the
kprobe program to. The new link_create uapi interface looks like:

  struct {
          __u32           flags;
          __u32           cnt;
          __aligned_u64   syms;
          __aligned_u64   addrs;
  } kprobe_multi;

The flags field allows single BPF_TRACE_KPROBE_MULTI bit to create
return multi kprobe.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-4-jolsa@kernel.org

kallsyms: Skip the name search for empty string

When kallsyms_lookup_name is called with empty string,
it will do futile search for it through all the symbols.

Skipping the search for empty string.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-3-jolsa@kernel.org

lib/sort: Add priv pointer to swap function

Adding support to have priv pointer in swap callback function.

Following the initial change on cmp callback functions [1]
and adding SWAP_WRAPPER macro to identify sort call of sort_r.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/20220316122419.933957-2-jolsa@kernel.org
[1] 4333fb96ca10 ("media: lib/sort.c: implement sort() variant taking context argument")

fprobe: Add a selftest for fprobe

Add a KUnit based selftest for fprobe interface.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735295554.1084943.18347620679928750960.stgit@devnote2

docs: fprobe: Add fprobe description to ftrace-use.rst

Add a documentation of fprobe for the user who needs
this interface.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735294272.1084943.12372175959382037397.stgit@devnote2

fprobe: Introduce FPROBE_FL_KPROBE_SHARED flag for fprobe

Introduce FPROBE_FL_KPROBE_SHARED flag for sharing fprobe callback with
kprobes safely from the viewpoint of recursion.

Since the recursion safety of the fprobe (and ftrace) is a bit different
from the kprobes, this may cause an issue if user wants to run the same
code from the fprobe and the kprobes.

The kprobes has per-cpu 'current_kprobe' variable which protects the
kprobe handler from recursion in any case. On the other hand, the fprobe
uses only ftrace_test_recursion_trylock(), which will allow interrupt
context calls another (or same) fprobe during the fprobe user handler is
running.

This is not a matter in cases if the common callback shared among the
kprobes and the fprobe has its own recursion detection, or it can handle
the recursion in the different contexts (normal/interrupt/NMI.)
But if it relies on the 'current_kprobe' recursion lock, it has to check
kprobe_running() and use kprobe_busy_*() APIs.

Fprobe has FPROBE_FL_KPROBE_SHARED flag to do this. If your common callback
code will be shared with kprobes, please set FPROBE_FL_KPROBE_SHARED
*before* registering the fprobe, like;

fprobe.flags = FPROBE_FL_KPROBE_SHARED;

register_fprobe(&fprobe, "func*", NULL);

This will protect your common callback from the nested call.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735293127.1084943.15687374237275817599.stgit@devnote2

fprobe: Add sample program for fprobe

Add a sample program for the fprobe. The sample_fprobe puts a fprobe on
kernel_clone() by default. This dump stack and some called address info
at the function entry and exit.

The sample_fprobe.ko gets 2 parameters.
- symbol: you can specify the comma separated symbols or wildcard symbol
pattern (in this case you can not use comma)
- stackdump: a bool value to enable or disable stack dump in the fprobe
handler.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735291987.1084943.4449670993752806840.stgit@devnote2

fprobe: Add exit_handler support

Add exit_handler to fprobe. fprobe + rethook allows us to hook the kernel
function return. The rethook will be enabled only if the
fprobe::exit_handler is set.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735290790.1084943.10601965782208052202.stgit@devnote2

ARM: rethook: Add rethook arm implementation

Add rethook arm implementation. Most of the code has been copied from
kretprobes on arm.
Since the arm's ftrace implementation is a bit special, this needs a
special care using from fprobe.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735289643.1084943.15184590256680485720.stgit@devnote2

powerpc: Add rethook support

Add rethook powerpc64 implementation. Most of the code has been copied from
kretprobes on powerpc64.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735288495.1084943.539630613772422267.stgit@devnote2

arm64: rethook: Add arm64 rethook implementation

Add rethook arm64 implementation. Most of the code has been copied from
kretprobes on arm64.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735287344.1084943.9787335632585653418.stgit@devnote2

rethook: x86: Add rethook x86 implementation

Add rethook for x86 implementation. Most of the code has been copied from
kretprobes on x86.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735286243.1084943.7477055110527046644.stgit@devnote2

rethook: Add a generic return hook

Add a return hook framework which hooks the function return. Most of the
logic came from the kretprobe, but this is independent from kretprobe.

Note that this is expected to be used with other function entry hooking
feature, like ftrace, fprobe, adn kprobes. Eventually this will replace
the kretprobe (e.g. kprobe + rethook = kretprobe), but at this moment,
this is just an additional hook.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735285066.1084943.9259661137330166643.stgit@devnote2

fprobe: Add ftrace based probe APIs

The fprobe is a wrapper API for ftrace function tracer.
Unlike kprobes, this probes only supports the function entry, but this
can probe multiple functions by one fprobe. The usage is similar, user
will set their callback to fprobe::entry_handler and call
register_fprobe*() with probed functions.
There are 3 registration interfaces,

- register_fprobe() takes filtering patterns of the functin names.
- register_fprobe_ips() takes an array of ftrace-location addresses.
- register_fprobe_syms() takes an array of function names.

The registered fprobes can be unregistered with unregister_fprobe().
e.g.

struct fprobe fp = { .entry_handler = user_handler };
const char *targets[] = { "func1", "func2", "func3"};
...

ret = register_fprobe_syms(&fp, targets, ARRAY_SIZE(targets));

...

unregister_fprobe(&fp);

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735283857.1084943.1154436951479395551.stgit@devnote2

ftrace: Add ftrace_set_filter_ips function

Adding ftrace_set_filter_ips function to be able to set filter on
multiple ip addresses at once.

With the kprobe multi attach interface we have cases where we need to
initialize ftrace_ops object with thousands of functions, so having
single function diving into ftrace_hash_move_and_update_ops with
ftrace_lock is faster.

The functions ips are passed as unsigned long array with count.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735282673.1084943.18310504594134769804.stgit@devnote2

selftests/bpf: Fix tunnel remote IP comments

In namespace at_ns0, the IP address of tnl dev is 10.1.1.100 which is the
overlay IP, and the ip address of veth0 is 172.16.1.100 which is the vtep
IP. When doing 'ping 10.1.1.100' from root namespace, the remote_ip should
be 172.16.1.100.

Fixes: 933a741e3b82 ("selftests/bpf: bpf tunnel test.")
Signed-off-by: Kaixi Fan <fankaixi.li@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220313164116.5889-1-fankaixi.li@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

veth: Allow jumbo frames in xdp mode

Allow increasing the MTU over page boundaries on veth devices
if the attached xdp program declares to support xdp fragments.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/d5dc039c3d4123426e7023a488c449181a7bc57f.1646989407.git.lorenzo@kernel.org

veth: Rework veth_xdp_rcv_skb in order to accept non-linear skb

Introduce veth_convert_skb_to_xdp_buff routine in order to
convert a non-linear skb into a xdp buffer. If the received skb
is cloned or shared, veth_convert_skb_to_xdp_buff will copy it
in a new skb composed by order-0 pages for the linear and the
fragmented area. Moreover veth_convert_skb_to_xdp_buff guarantees
we have enough headroom for xdp.
This is a preliminary patch to allow attaching xdp programs with frags
support on veth devices.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/8d228b106bc1903571afd1d77e797bffe9a5ea7c.1646989407.git.lorenzo@kernel.org

net: veth: Account total xdp_frame len running ndo_xdp_xmit

Even if this is a theoretical issue since it is not possible to perform
XDP_REDIRECT on a non-linear xdp_frame, veth driver does not account
paged area in ndo_xdp_xmit function pointer.
Introduce xdp_get_frame_len utility routine to get the xdp_frame full
length and account total frame size running XDP_REDIRECT of a
non-linear xdp frame into a veth device.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Hoiland-Jorgensen <toke@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/54f9fd3bb65d190daf2c0bbae2f852ff16cfbaa0.1646989407.git.lorenzo@kernel.org

selftests/bpf: Test subprog jit when toggle bpf_jit_harden repeatedly

When bpf_jit_harden is toggled between 0 and 2, subprog jit may fail
due to inconsistent twice read values of bpf_jit_harden during jit. So
add a test to ensure the problem is fixed.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220309123321.2400262-5-houtao1@huawei.com

bpf: Fix net.core.bpf_jit_harden race

It is the bpf_jit_harden counterpart to commit 60b58afc96c9 ("bpf: fix
net.core.bpf_jit_enable race"). bpf_jit_harden will be tested twice
for each subprog if there are subprogs in bpf program and constant
blinding may increase the length of program, so when running
"./test_progs -t subprogs" and toggling bpf_jit_harden between 0 and 2,
jit_subprogs may fail because constant blinding increases the length
of subprog instructions during extra passs.

So cache the value of bpf_jit_blinding_enabled() during program
allocation, and use the cached value during constant blinding, subprog
JITing and args tracking of tail call.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220309123321.2400262-4-houtao1@huawei.com

bpf, x86: Fall back to interpreter mode when extra pass fails

Extra pass for subprog jit may fail (e.g. due to bpf_jit_harden race),
but bpf_func is not cleared for the subprog and jit_subprogs will
succeed. The running of the bpf program may lead to oops because the
memory for the jited subprog image has already been freed.

So fall back to interpreter mode by clearing bpf_func/jited/jited_len
when extra pass fails.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220309123321.2400262-2-houtao1@huawei.com

Merge branch 'Remove libcap dependency from bpf selftests'

Martin KaFai Lau says:

====================

After upgrading to the newer libcap (>= 2.60),
the libcap commit aca076443591 ("Make cap_t operations thread safe.")
added a "__u8 mutex;" to the "struct _cap_struct". It caused a few byte
shift that breaks the assumption made in the "struct libcap" definition
in test_verifier.c.

This set is to remove the libcap dependency from the bpf selftests.

v2:
- Define CAP_PERFMON and CAP_BPF when the older <linux/capability.h>
does not have them. (Andrii)
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

bpf: selftests: Remove libcap usage from test_progs

This patch removes the libcap usage from test_progs.
bind_perm.c is the only user. cap_*_effective() helpers added in the
earlier patch are directly used instead.

No other selftest binary is using libcap, so '-lcap' is also removed
from the Makefile.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220316173835.2039334-1-kafai@fb.com

bpf: selftests: Remove libcap usage from test_verifier

This patch removes the libcap usage from test_verifier.
The cap_*_effective() helpers added in the earlier patch are
used instead.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220316173829.2038682-1-kafai@fb.com

bpf: selftests: Add helpers to directly use the capget and capset syscall

After upgrading to the newer libcap (>= 2.60),
the libcap commit aca076443591 ("Make cap_t operations thread safe.")
added a "__u8 mutex;" to the "struct _cap_struct".  It caused a few byte
shift that breaks the assumption made in the "struct libcap" definition
in test_verifier.c.

The bpf selftest usage only needs to enable and disable the effective
caps of the running task.  It is easier to directly syscall the
capget and capset instead.  It can also remove the libcap
library dependency.

The cap_helpers.{c,h} is added.  One __u64 is used for all CAP_*
bits instead of two __u32.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220316173823.2036955-1-kafai@fb.com

bpftool: man: Add missing top level docs

The top-level (bpftool.8) man page was missing docs for a few
subcommands and their respective sub-sub-commands.

This commit brings the top level man page up to date. Note that I've
kept the ordering of the subcommands the same as in `bpftool help`.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/3049ef5dc509c0d1832f0a8b2dba2ccaad0af688.1647213551.git.dxu@dxuuu.xyz

bpftool: Add bpf_cookie to link output

Commit 82e6b1eee6a8 ("bpf: Allow to specify user-provided bpf_cookie for
BPF perf links") introduced the concept of user specified bpf_cookie,
which could be accessed by BPF programs using bpf_get_attach_cookie().
For troubleshooting purposes it is convenient to expose bpf_cookie via
bpftool as well, so there is no need to meddle with the target BPF
program itself.

Implemented using the pid iterator BPF program to actually fetch
bpf_cookies, which allows constraining code changes only to bpftool.

$ bpftool link
1: type 7  prog 5
        bpf_cookie 123
        pids bootstrap(81)

Signed-off-by: Dmitrii Dolgov <9erthalion6@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220309163112.24141-1-9erthalion6@gmail.com

selftests/bpf: Clean up array_size.cocci warnings

Clean up the array_size.cocci warnings under tools/testing/selftests/bpf/:

Use `ARRAY_SIZE(arr)` instead of forms like `sizeof(arr)/sizeof(arr[0])`.

tools/testing/selftests/bpf/test_cgroup_storage.c uses ARRAY_SIZE() defined
in tools/include/linux/kernel.h (sys/sysinfo.h -> linux/kernel.h), while
others use ARRAY_SIZE() in bpf_util.h.

Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220315130143.2403-1-guozhengkui@vivo.com

samples/bpf, xdpsock: Fix race when running for fix duration of time

When running xdpsock for a fix duration of time before terminating
using --duration=<n>, there is a race condition that may cause xdpsock
to terminate immediately.

When running for a fixed duration of time the check to determine when to
terminate execution is in is_benchmark_done() and is being executed in
the context of the poller thread,

    if (opt_duration > 0) {
            unsigned long dt = (get_nsecs() - start_time);

            if (dt >= opt_duration)
                    benchmark_done = true;
    }

However start_time is only set after the poller thread have been
created. This leaves a small window when the poller thread is starting
and calls is_benchmark_done() for the first time that start_time is not
yet set. In that case start_time have its initial value of 0 and the
duration check fails as it do not correlate correctly for the
applications start time and immediately sets benchmark_done which in
turn terminates the xdpsock application.

Fix this by setting start_time before creating the poller thread.

Fixes: d3f11b018f6c ("samples/bpf: xdpsock: Add duration option to specify how long to run")
Signed-off-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220315102948.466436-1-niklas.soderlund@corigine.com

bpf, sockmap: Fix double uncharge the mem of sk_msg

If tcp_bpf_sendmsg is running during a tear down operation, psock may be
freed.

tcp_bpf_sendmsg()
tcp_bpf_send_verdict()
  sk_msg_return()
  tcp_bpf_sendmsg_redir()
   unlikely(!psock))
     sk_msg_free()

The mem of msg has been uncharged in tcp_bpf_send_verdict() by
sk_msg_return(), and would be uncharged by sk_msg_free() again. When psock
is null, we can simply returning an error code, this would then trigger
the sk_msg_free_nocharge in the error path of __SK_REDIRECT and would have
the side effect of throwing an error up to user space. This would be a
slight change in behavior from user side but would look the same as an
error if the redirect on the socket threw an error.

This issue can cause the following info:
WARNING: CPU: 0 PID: 2136 at net/ipv4/af_inet.c:155 inet_sock_destruct+0x13c/0x260
Call Trace:
<TASK>
__sk_destruct+0x24/0x1f0
sk_psock_destroy+0x19b/0x1c0
process_one_work+0x1b3/0x3c0
worker_thread+0x30/0x350
? process_one_work+0x3c0/0x3c0
kthread+0xe6/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220304081145.2037182-5-wangyufen@huawei.com

bpf, sockmap: Fix more uncharged while msg has more_data

In tcp_bpf_send_verdict(), if msg has more data after
tcp_bpf_sendmsg_redir():

tcp_bpf_send_verdict()
tosend = msg->sg.size  //msg->sg.size = 22220
case __SK_REDIRECT:
  sk_msg_return()  //uncharged msg->sg.size(22220) sk->sk_forward_alloc
  tcp_bpf_sendmsg_redir() //after tcp_bpf_sendmsg_redir, msg->sg.size=11000
goto more_data;
tosend = msg->sg.size  //msg->sg.size = 11000
case __SK_REDIRECT:
  sk_msg_return()  //uncharged msg->sg.size(11000) to sk->sk_forward_alloc

The msg->sg.size(11000) has been uncharged twice, to fix we can charge the
remaining msg->sg.size before goto more data.

This issue can cause the following info:
WARNING: CPU: 0 PID: 9860 at net/core/stream.c:208 sk_stream_kill_queues+0xd4/0x1a0
Call Trace:
<TASK>
inet_csk_destroy_sock+0x55/0x110
__tcp_close+0x279/0x470
tcp_close+0x1f/0x60
inet_release+0x3f/0x80
__sock_release+0x3d/0xb0
sock_close+0x11/0x20
__fput+0x92/0x250
task_work_run+0x6a/0xa0
do_exit+0x33b/0xb60
do_group_exit+0x2f/0xa0
get_signal+0xb6/0x950
arch_do_signal_or_restart+0xac/0x2a0
? vfs_write+0x237/0x290
exit_to_user_mode_prepare+0xa9/0x200
syscall_exit_to_user_mode+0x12/0x30
do_syscall_64+0x46/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
</TASK>

WARNING: CPU: 0 PID: 2136 at net/ipv4/af_inet.c:155 inet_sock_destruct+0x13c/0x260
Call Trace:
<TASK>
__sk_destruct+0x24/0x1f0
sk_psock_destroy+0x19b/0x1c0
process_one_work+0x1b3/0x3c0
worker_thread+0x30/0x350
? process_one_work+0x3c0/0x3c0
kthread+0xe6/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220304081145.2037182-4-wangyufen@huawei.com

bpf, sockmap: Fix memleak in tcp_bpf_sendmsg while sk msg is full

If tcp_bpf_sendmsg() is running while sk msg is full. When sk_msg_alloc()
returns -ENOMEM error, tcp_bpf_sendmsg() goes to wait_for_memory. If partial
memory has been alloced by sk_msg_alloc(), that is, msg_tx->sg.size is
greater than osize after sk_msg_alloc(), memleak occurs. To fix we use
sk_msg_trim() to release the allocated memory, then goto wait for memory.

Other call paths of sk_msg_alloc() have the similar issue, such as
tls_sw_sendmsg(), so handle sk_msg_trim logic inside sk_msg_alloc(),
as Cong Wang suggested.

This issue can cause the following info:
WARNING: CPU: 3 PID: 7950 at net/core/stream.c:208 sk_stream_kill_queues+0xd4/0x1a0
Call Trace:
<TASK>
inet_csk_destroy_sock+0x55/0x110
__tcp_close+0x279/0x470
tcp_close+0x1f/0x60
inet_release+0x3f/0x80
__sock_release+0x3d/0xb0
sock_close+0x11/0x20
__fput+0x92/0x250
task_work_run+0x6a/0xa0
do_exit+0x33b/0xb60
do_group_exit+0x2f/0xa0
get_signal+0xb6/0x950
arch_do_signal_or_restart+0xac/0x2a0
exit_to_user_mode_prepare+0xa9/0x200
syscall_exit_to_user_mode+0x12/0x30
do_syscall_64+0x46/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
</TASK>

WARNING: CPU: 3 PID: 2094 at net/ipv4/af_inet.c:155 inet_sock_destruct+0x13c/0x260
Call Trace:
<TASK>
__sk_destruct+0x24/0x1f0
sk_psock_destroy+0x19b/0x1c0
process_one_work+0x1b3/0x3c0
kthread+0xe6/0x110
ret_from_fork+0x22/0x30
</TASK>

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220304081145.2037182-3-wangyufen@huawei.com

bpf, sockmap: Fix memleak in sk_psock_queue_msg

If tcp_bpf_sendmsg is running during a tear down operation we may enqueue
data on the ingress msg queue while tear down is trying to free it.

sk1 (redirect sk2)                         sk2
-------------------                      ---------------
tcp_bpf_sendmsg()
tcp_bpf_send_verdict()
  tcp_bpf_sendmsg_redir()
   bpf_tcp_ingress()
                                          sock_map_close()
                                           lock_sock()
    lock_sock() ... blocking
                                           sk_psock_stop
                                            sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
                                           release_sock(sk);
    lock_sock()
    sk_mem_charge()
    get_page()
    sk_psock_queue_msg()
     sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED);
      drop_sk_msg()
    release_sock()

While drop_sk_msg(), the msg has charged memory form sk by sk_mem_charge
and has sg pages need to put. To fix we use sk_msg_free() and then kfee()
msg.

This issue can cause the following info:
WARNING: CPU: 0 PID: 9202 at net/core/stream.c:205 sk_stream_kill_queues+0xc8/0xe0
Call Trace:
<IRQ>
inet_csk_destroy_sock+0x55/0x110
tcp_rcv_state_process+0xe5f/0xe90
? sk_filter_trim_cap+0x10d/0x230
? tcp_v4_do_rcv+0x161/0x250
tcp_v4_do_rcv+0x161/0x250
tcp_v4_rcv+0xc3a/0xce0
ip_protocol_deliver_rcu+0x3d/0x230
ip_local_deliver_finish+0x54/0x60
ip_local_deliver+0xfd/0x110
? ip_protocol_deliver_rcu+0x230/0x230
ip_rcv+0xd6/0x100
? ip_local_deliver+0x110/0x110
__netif_receive_skb_one_core+0x85/0xa0
process_backlog+0xa4/0x160
__napi_poll+0x29/0x1b0
net_rx_action+0x287/0x300
__do_softirq+0xff/0x2fc
do_softirq+0x79/0x90
</IRQ>

WARNING: CPU: 0 PID: 531 at net/ipv4/af_inet.c:154 inet_sock_destruct+0x175/0x1b0
Call Trace:
<TASK>
__sk_destruct+0x24/0x1f0
sk_psock_destroy+0x19b/0x1c0
process_one_work+0x1b3/0x3c0
? process_one_work+0x3c0/0x3c0
worker_thread+0x30/0x350
? process_one_work+0x3c0/0x3c0
kthread+0xe6/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>

Fixes: 9635720b7c88 ("bpf, sockmap: Fix memleak on ingress msg enqueue")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220304081145.2037182-2-wangyufen@huawei.com

selftests/bpf: Fix a clang compilation error for send_signal.c

Building selftests/bpf with latest clang compiler (clang15 built
from source), I hit the following compilation error:

  /.../prog_tests/send_signal.c:43:16: error: variable 'j' set but not used [-Werror,-Wunused-but-set-variable]
                  volatile int j = 0;
                               ^
  1 error generated.

The problem also exists with clang13 and clang14. clang12 is okay.

In send_signal.c, we have the following code ...

  volatile int j = 0;
  [...]
  for (int i = 0; i < 100000000 && !sigusr1_received; i++)
    j /= i + 1;

... to burn CPU cycles so bpf_send_signal() helper can be tested
in NMI mode.

Slightly changing 'j /= i + 1' to 'j /= i + j + 1' or 'j++' can
fix the problem. Further investigation indicated this should be
a clang bug ([1]). The upstream fix will be proposed later. But it
is a good idea to workaround the issue to unblock people who build
kernel/selftests with clang.

  [1] https://discourse.llvm.org/t/strange-clang-unused-but-set-variable-error-with-volatile-variables/60841

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220311003721.2177170-1-yhs@fb.com

selftests/bpf: Add a test for maximum packet size in xdp_do_redirect

This adds an extra test to the xdp_do_redirect selftest for XDP live packet
mode, which verifies that the maximum permissible packet size is accepted
without any errors, and that a too big packet is correctly rejected.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220310225621.53374-2-toke@redhat.com

bpf, test_run: Fix packet size check for live packet mode

The live packet mode uses some extra space at the start of each page to
cache data structures so they don't have to be rebuilt at every repetition.
This space wasn't correctly accounted for in the size checking of the
arguments supplied to userspace. In addition, the definition of the frame
size should include the size of the skb_shared_info (as there is other
logic that subtracts the size of this).

Together, these mistakes resulted in userspace being able to trip the
XDP_WARN() in xdp_update_frame_from_buff(), which syzbot discovered in
short order. Fix this by changing the frame size define and adding the
extra headroom to the bpf_prog_test_run_xdp() function. Also drop the
max_len parameter to the page_pool init, since this is related to DMA which
is not used for the page pool instance in PROG_TEST_RUN.

Fixes: b530e9e1063e ("bpf: Add "live packet" mode for XDP in BPF_PROG_RUN")
Reported-by: syzbot+0e91362d99386dc5de99@syzkaller.appspotmail.com
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220310225621.53374-1-toke@redhat.com

compiler_types: Refactor the use of btf_type_tag attribute.

Previous patches have introduced the compiler attribute btf_type_tag for
__user and __percpu. The availability of this attribute depends on
some CONFIGs and compiler support. This patch refactors the use
of btf_type_tag by introducing BTF_TYPE_TAG, which hides all the
dependencies.

No functional change.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220310211655.3173786-1-haoluo@google.com

Merge branch 'bpf-lsm: Extend interoperability with IMA'

Roberto Sassu says:

====================
Extend the interoperability with IMA, to give wider flexibility for the
implementation of integrity-focused LSMs based on eBPF.

Patch 1 fixes some style issues.

Patches 2-6 give the ability to eBPF-based LSMs to take advantage of the
measurement capability of IMA without needing to setup a policy in IMA
(those LSMs might implement the policy capability themselves).

Patches 7-9 allow eBPF-based LSMs to evaluate files read by the kernel.

Changelog

v2:
- Add better description to patch 1 (suggested by Shuah)
- Recalculate digest if it is not fresh (when IMA_COLLECTED flag not set)
- Move declaration of bpf_ima_file_hash() at the end (suggested by
  Yonghong)
- Add tests to check if the digest has been recalculated
- Add deny test for bpf_kernel_read_file()
- Add description to tests

v1:
- Modify ima_file_hash() only and allow the usage of the function with the
  modified behavior by eBPF-based LSMs through the new function
  bpf_ima_file_hash() (suggested by Mimi)
- Make bpf_lsm_kernel_read_file() sleepable so that bpf_ima_inode_hash()
  and bpf_ima_file_hash() can be called inside the implementation of
  eBPF-based LSMs for this hook
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Check that bpf_kernel_read_file() denies reading IMA policy

Check that bpf_kernel_read_file() denies the reading of an IMA policy, by
ensuring that ima_setup.sh exits with an error.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220302111404.193900-10-roberto.sassu@huawei.com

selftests/bpf: Add test for bpf_lsm_kernel_read_file()

Test the ability of bpf_lsm_kernel_read_file() to call the sleepable
functions bpf_ima_inode_hash() or bpf_ima_file_hash() to obtain a
measurement of a loaded IMA policy.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220302111404.193900-9-roberto.sassu@huawei.com

bpf-lsm: Make bpf_lsm_kernel_read_file() as sleepable

Make bpf_lsm_kernel_read_file() as sleepable, so that bpf_ima_inode_hash()
or bpf_ima_file_hash() can be called inside the implementation of this
hook.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220302111404.193900-8-roberto.sassu@huawei.com

selftests/bpf: Check if the digest is refreshed after a file write

Verify that bpf_ima_inode_hash() returns a non-fresh digest after a file
write, and that bpf_ima_file_hash() returns a fresh digest. Verification is
done by requesting the digest from the bprm_creds_for_exec hook, called
before ima_bprm_check().

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220302111404.193900-7-roberto.sassu@huawei.com

selftests/bpf: Add test for bpf_ima_file_hash()

Add new test to ensure that bpf_ima_file_hash() returns the digest of the
executed files.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220302111404.193900-6-roberto.sassu@huawei.com

selftests/bpf: Move sample generation code to ima_test_common()

Move sample generator code to ima_test_common() so that the new function
can be called by multiple LSM hooks.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220302111404.193900-5-roberto.sassu@huawei.com

bpf-lsm: Introduce new helper bpf_ima_file_hash()

ima_file_hash() has been modified to calculate the measurement of a file on
demand, if it has not been already performed by IMA or the measurement is
not fresh. For compatibility reasons, ima_inode_hash() remains unchanged.

Keep the same approach in eBPF and introduce the new helper
bpf_ima_file_hash() to take advantage of the modified behavior of
ima_file_hash().

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220302111404.193900-4-roberto.sassu@huawei.com

ima: Always return a file measurement in ima_file_hash()

__ima_inode_hash() checks if a digest has been already calculated by
looking for the integrity_iint_cache structure associated to the passed
inode.

Users of ima_file_hash() (e.g. eBPF) might be interested in obtaining the
information without having to setup an IMA policy so that the digest is
always available at the time they call this function.

In addition, they likely expect the digest to be fresh, e.g. recalculated
by IMA after a file write. Although getting the digest from the
bprm_committed_creds hook (as in the eBPF test) ensures that the digest is
fresh, as the IMA hook is executed before that hook, this is not always the
case (e.g. for the mmap_file hook).

Call ima_collect_measurement() in __ima_inode_hash(), if the file
descriptor is available (passed by ima_file_hash()) and the digest is not
available/not fresh, and store the file measurement in a temporary
integrity_iint_cache structure.

This change does not cause memory usage increase, due to using the
temporary integrity_iint_cache structure, and due to freeing the
ima_digest_data structure inside integrity_iint_cache before exiting from
__ima_inode_hash().

For compatibility reasons, the behavior of ima_inode_hash() remains
unchanged.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20220302111404.193900-3-roberto.sassu@huawei.com

ima: Fix documentation-related warnings in ima_main.c

Fix the following warnings in ima_main.c, displayed with W=n make argument:

security/integrity/ima/ima_main.c:432: warning: Function parameter or
                          member 'vma' not described in 'ima_file_mprotect'
security/integrity/ima/ima_main.c:636: warning: Function parameter or
                  member 'inode' not described in 'ima_post_create_tmpfile'
security/integrity/ima/ima_main.c:636: warning: Excess function parameter
                            'file' description in 'ima_post_create_tmpfile'
security/integrity/ima/ima_main.c:843: warning: Function parameter or
                     member 'load_id' not described in 'ima_post_load_data'
security/integrity/ima/ima_main.c:843: warning: Excess function parameter
                                   'id' description in 'ima_post_load_data'

Also, fix some style issues in the description of ima_post_create_tmpfile()
and ima_post_path_mknod().

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20220302111404.193900-2-roberto.sassu@huawei.com

bpftool: Ensure bytes_memlock json output is correct

If a BPF map is created over 2^32 the memlock value as displayed in JSON
format will be incorrect. Use atoll instead of atoi so that the correct
number is displayed.

  ```
  $ bpftool map create /sys/fs/bpf/test_bpfmap type hash key 4 \
    value 1024 entries 4194304 name test_bpfmap
  $ bpftool map list
  1: hash  name test_bpfmap  flags 0x0
          key 4B  value 1024B  max_entries 4194304  memlock 4328521728B
  $ sudo bpftool map list -j | jq .[].bytes_memlock
  33554432
  ```

Signed-off-by: Chris J Arges <carges@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/b6601087-0b11-33cc-904a-1133d1500a10@cloudflare.com

bpf: Use offsetofend() to simplify macro definition

Use offsetofend() instead of offsetof() + sizeof() to simplify
MIN_BPF_LINEINFO_SIZE macro definition.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://lore.kernel.org/bpf/20220310161518.534544-1-ytcoode@gmail.com

bpf: Fix comment for helper bpf_current_task_under_cgroup()

Fix the descriptions of the return values of helper bpf_current_task_under_cgroup().

Fixes: c6b5fb8690fa ("bpf: add documentation for eBPF helpers (42-50)")
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220310155335.1278783-1-hengqi.chen@gmail.com

Merge branch 'bpf-tstamp-follow-ups'

Martin KaFai Lau says:

====================
This set is a follow up on the bpf side based on discussion [0].

Patch 1 is to remove some skbuff macros that are used in bpf filter.c.

Patch 2 and 3 are to simplify the bpf insn rewrite on __sk_buff->tstamp.

Patch 4 is to simplify the bpf uapi by modeling the __sk_buff->tstamp
and __sk_buff->tstamp_type (was delivery_time_type) the same as its kernel
counter part skb->tstamp and skb->mono_delivery_time.

Patch 5 is to adjust the bpf selftests due to changes in patch 4.

[0]: https://lore.kernel.org/bpf/419d994e-ff61-7c11-0ec7-11fefcb0186e@iogearbox.net/
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

bpf: selftests: Update tests after s/delivery_time/tstamp/ change in bpf.h

The previous patch made the follow changes:
- s/delivery_time_type/tstamp_type/
- s/bpf_skb_set_delivery_time/bpf_skb_set_tstamp/
- BPF_SKB_DELIVERY_TIME_* to BPF_SKB_TSTAMP_*

This patch is to change the test_tc_dtime.c to reflect the above.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220309090515.3712742-1-kafai@fb.com

bpf: Remove BPF_SKB_DELIVERY_TIME_NONE and rename s/delivery_time_/tstamp_/

This patch is to simplify the uapi bpf.h regarding to the tstamp type
and use a similar way as the kernel to describe the value stored
in __sk_buff->tstamp.

My earlier thought was to avoid describing the semantic and
clock base for the rcv timestamp until there is more clarity
on the use case, so the __sk_buff->delivery_time_type naming instead
of __sk_buff->tstamp_type.

With some thoughts, it can reuse the UNSPEC naming.  This patch first
removes BPF_SKB_DELIVERY_TIME_NONE and also

rename BPF_SKB_DELIVERY_TIME_UNSPEC to BPF_SKB_TSTAMP_UNSPEC
and    BPF_SKB_DELIVERY_TIME_MONO   to BPF_SKB_TSTAMP_DELIVERY_MONO.

The semantic of BPF_SKB_TSTAMP_DELIVERY_MONO is the same:
__sk_buff->tstamp has delivery time in mono clock base.

BPF_SKB_TSTAMP_UNSPEC means __sk_buff->tstamp has the (rcv)
tstamp at ingress and the delivery time at egress.  At egress,
the clock base could be found from skb->sk->sk_clockid.
__sk_buff->tstamp == 0 naturally means NONE, so NONE is not needed.

With BPF_SKB_TSTAMP_UNSPEC for the rcv tstamp at ingress,
the __sk_buff->delivery_time_type is also renamed to __sk_buff->tstamp_type
which was also suggested in the earlier discussion:
https://lore.kernel.org/bpf/b181acbe-caf8-502d-4b7b-7d96b9fc5d55@iogearbox.net/

The above will then make __sk_buff->tstamp and __sk_buff->tstamp_type
the same as its kernel skb->tstamp and skb->mono_delivery_time
counter part.

The internal kernel function bpf_skb_convert_dtime_type_read() is then
renamed to bpf_skb_convert_tstamp_type_read() and it can be simplified
with the BPF_SKB_DELIVERY_TIME_NONE gone.  A BPF_ALU32_IMM(BPF_AND)
insn is also saved by using BPF_JMP32_IMM(BPF_JSET).

The bpf helper bpf_skb_set_delivery_time() is also renamed to
bpf_skb_set_tstamp().  The arg name is changed from dtime
to tstamp also.  It only allows setting tstamp 0 for
BPF_SKB_TSTAMP_UNSPEC and it could be relaxed later
if there is use case to change mono delivery time to
non mono.

prog->delivery_time_access is also renamed to prog->tstamp_type_access.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220309090509.3712315-1-kafai@fb.com

bpf: Simplify insn rewrite on BPF_WRITE __sk_buff->tstamp

BPF_JMP32_IMM(BPF_JSET) is used to save a BPF_ALU32_IMM(BPF_AND).

The skb->tc_at_ingress and skb->mono_delivery_time are at the same
offset, so only one BPF_LDX_MEM(BPF_B) is needed.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220309090502.3711982-1-kafai@fb.com