KCSAN: data-race in drop_nlink / generic_fillattr (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b6505459 Linux 5.10-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=144a8809500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=2a43639c4b043177efc9
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+2a4363...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in drop_nlink / generic_fillattr

write to 0xffff888044eb0448 of 4 bytes by task 27096 on cpu 0:
drop_nlink+0x37/0x90 fs/inode.c:306
shmem_unlink+0x162/0x180 mm/shmem.c:3033
shmem_rename2+0x2f5/0x420 mm/shmem.c:3125
vfs_rename+0x8ef/0xe20 fs/namei.c:4310
do_renameat2+0x56c/0x930 fs/namei.c:4457
__do_sys_rename fs/namei.c:4503 [inline]
__se_sys_rename fs/namei.c:4501 [inline]
__x64_sys_rename+0x3a/0x40 fs/namei.c:4501
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888044eb0448 of 4 bytes by task 4897 on cpu 1:
generic_fillattr+0x74/0x180 fs/stat.c:41
shmem_getattr+0x227/0x2c0 mm/shmem.c:1075
vfs_getattr_nosec fs/stat.c:87 [inline]
vfs_getattr fs/stat.c:124 [inline]
vfs_fstat+0x1c9/0x390 fs/stat.c:146
__do_sys_newfstat fs/stat.c:386 [inline]
__se_sys_newfstat+0x35/0x240 fs/stat.c:383
__x64_sys_newfstat+0x2d/0x40 fs/stat.c:383
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: 1 PID: 4897 Comm: systemd-udevd Not tainted 5.10.0-rc6-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.