f2fs: avoid false alarm of circular locking
======================================================
WARNING: possible circular locking dependency detected
6.5.0-rc5-syzkaller-00353-gae545c3283dc #0 Not tainted
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syz-executor273/5027 is trying to acquire lock:
ffff888077fe1fb0 (&fi->i_sem){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2133 [inline]
ffff888077fe1fb0 (&fi->i_sem){+.+.}-{3:3}, at: f2fs_add_inline_entry+0x300/0x6f0 fs/f2fs/inline.c:644
but task is already holding lock:
ffff888077fe07c8 (&fi->i_xattr_sem){.+.+}-{3:3}, at: f2fs_down_read fs/f2fs/f2fs.h:2108 [inline]
ffff888077fe07c8 (&fi->i_xattr_sem){.+.+}-{3:3}, at: f2fs_add_dentry+0x92/0x230 fs/f2fs/dir.c:783
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&fi->i_xattr_sem){.+.+}-{3:3}:
down_read+0x9c/0x470 kernel/locking/rwsem.c:1520
f2fs_down_read fs/f2fs/f2fs.h:2108 [inline]
f2fs_getxattr+0xb1e/0x12c0 fs/f2fs/xattr.c:532
__f2fs_get_acl+0x5a/0x900 fs/f2fs/acl.c:179
f2fs_acl_create fs/f2fs/acl.c:377 [inline]
f2fs_init_acl+0x15c/0xb30 fs/f2fs/acl.c:420
f2fs_init_inode_metadata+0x159/0x1290 fs/f2fs/dir.c:558
f2fs_add_regular_entry+0x79e/0xb90 fs/f2fs/dir.c:740
f2fs_add_dentry+0x1de/0x230 fs/f2fs/dir.c:788
f2fs_do_add_link+0x190/0x280 fs/f2fs/dir.c:827
f2fs_add_link fs/f2fs/f2fs.h:3554 [inline]
f2fs_mkdir+0x377/0x620 fs/f2fs/namei.c:781
vfs_mkdir+0x532/0x7e0 fs/namei.c:4117
do_mkdirat+0x2a9/0x330 fs/namei.c:4140
__do_sys_mkdir fs/namei.c:4160 [inline]
__se_sys_mkdir fs/namei.c:4158 [inline]
__x64_sys_mkdir+0xf2/0x140 fs/namei.c:4158
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
-> #0 (&fi->i_sem){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3142 [inline]
check_prevs_add kernel/locking/lockdep.c:3261 [inline]
validate_chain kernel/locking/lockdep.c:3876 [inline]
__lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5144
lock_acquire kernel/locking/lockdep.c:5761 [inline]
lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726
down_write+0x93/0x200 kernel/locking/rwsem.c:1573
f2fs_down_write fs/f2fs/f2fs.h:2133 [inline]
f2fs_add_inline_entry+0x300/0x6f0 fs/f2fs/inline.c:644
f2fs_add_dentry+0xa6/0x230 fs/f2fs/dir.c:784
f2fs_do_add_link+0x190/0x280 fs/f2fs/dir.c:827
f2fs_add_link fs/f2fs/f2fs.h:3554 [inline]
f2fs_mkdir+0x377/0x620 fs/f2fs/namei.c:781
vfs_mkdir+0x532/0x7e0 fs/namei.c:4117
ovl_do_mkdir fs/overlayfs/overlayfs.h:196 [inline]
ovl_mkdir_real+0xb5/0x370 fs/overlayfs/dir.c:146
ovl_workdir_create+0x3de/0x820 fs/overlayfs/super.c:309
ovl_make_workdir fs/overlayfs/super.c:711 [inline]
ovl_get_workdir fs/overlayfs/super.c:864 [inline]
ovl_fill_super+0xdab/0x6180 fs/overlayfs/super.c:1400
vfs_get_super+0xf9/0x290 fs/super.c:1152
vfs_get_tree+0x88/0x350 fs/super.c:1519
do_new_mount fs/namespace.c:3335 [inline]
path_mount+0x1492/0x1ed0 fs/namespace.c:3662
do_mount fs/namespace.c:3675 [inline]
__do_sys_mount fs/namespace.c:3884 [inline]
__se_sys_mount fs/namespace.c:3861 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:3861
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
rlock(&fi->i_xattr_sem);
lock(&fi->i_sem);
lock(&fi->i_xattr_sem);
lock(&fi->i_sem);
Cc: <stable@vger.kernel.org>
Reported-and-tested-by: syzbot+e5600587fa9cbf8e3826@syzkaller.appspotmail.com
Fixes:
5eda1ad1aaff "f2fs: fix deadlock in i_xattr_sem and inode page lock"
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>