KCSAN: data-race in lookup_fast / retain_dentry (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a349e4c6 Merge tag 'xfs-5.10-fixes-7' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=135a54d1500000
kernel config: https://syzkaller.appspot.com/x/.config?x=89a86a84f1254241
dashboard link: https://syzkaller.appspot.com/bug?extid=cc3faff1446001bdd19d
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cc3faf...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in lookup_fast / retain_dentry

write to 0xffff88800e66ca80 of 4 bytes by task 12673 on cpu 1:
retain_dentry+0x1c3/0x240 fs/dcache.c:659
dput+0x10e/0x420 fs/dcache.c:873
path_put+0x1b/0x30 fs/namei.c:496
do_utimes_path fs/utimes.c:98 [inline]
do_utimes fs/utimes.c:143 [inline]
do_futimesat fs/utimes.c:197 [inline]
__do_sys_utimes fs/utimes.c:210 [inline]
__se_sys_utimes+0x105/0x1f0 fs/utimes.c:207
__x64_sys_utimes+0x2d/0x40 fs/utimes.c:207
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88800e66ca80 of 4 bytes by task 12675 on cpu 0:
d_revalidate fs/namei.c:767 [inline]
lookup_fast+0x15f/0x370 fs/namei.c:1493
walk_component+0x5c/0x350 fs/namei.c:1857
lookup_last fs/namei.c:2310 [inline]
path_lookupat+0x11d/0x550 fs/namei.c:2334
filename_lookup+0xf2/0x380 fs/namei.c:2367
user_path_at_empty+0x3b/0x50 fs/namei.c:2647
user_path_at include/linux/namei.h:59 [inline]
path_setxattr+0x4c/0x170 fs/xattr.c:562
__do_sys_setxattr fs/xattr.c:582 [inline]
__se_sys_setxattr fs/xattr.c:578 [inline]
__x64_sys_setxattr+0x69/0x80 fs/xattr.c:578
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12675 Comm: syz-executor.5 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.