KCSAN: data-race in generic_fillattr / shmem_unlink (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: aad611a868d1 Merge tag 'perf-tools-fixes-for-v5.17-2022-03..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1136649d700000
kernel config: https://syzkaller.appspot.com/x/.config?x=5f8eb792c7b91c8f
dashboard link: https://syzkaller.appspot.com/bug?extid=d7d89c7070ae862afd7c
compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
CC: [ak...@linux-foundation.org hu...@google.com linux-...@vger.kernel.org linu...@kvack.org]

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+d7d89c...@syzkaller.appspotmail.com

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

write to 0xffff8881047fbd08 of 8 bytes by task 5463 on cpu 0:
shmem_unlink+0x117/0x1a0 mm/shmem.c:2917
shmem_rename2+0x199/0x2d0 mm/shmem.c:2993
vfs_rename+0x91b/0xd20 fs/namei.c:4677
do_renameat2+0x6d7/0xa20 fs/namei.c:4828
__do_sys_rename fs/namei.c:4874 [inline]
__se_sys_rename fs/namei.c:4872 [inline]
__x64_sys_rename+0x58/0x60 fs/namei.c:4872
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881047fbd08 of 8 bytes by task 5460 on cpu 1:
i_size_read include/linux/fs.h:885 [inline]
generic_fillattr+0x203/0x2b0 fs/stat.c:53
vfs_getattr_nosec fs/stat.c:126 [inline]
vfs_getattr fs/stat.c:160 [inline]
vfs_statx+0x265/0x3c0 fs/stat.c:225
vfs_fstatat fs/stat.c:243 [inline]
__do_sys_newfstatat fs/stat.c:412 [inline]
__se_sys_newfstatat+0x63/0x260 fs/stat.c:406
__x64_sys_newfstatat+0x51/0x60 fs/stat.c:406
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000000000000161c -> 0x0000000000001608

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5460 Comm: udevd Not tainted 5.17.0-rc7-syzkaller-00235-gaad611a868d1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[Dmitry Vyukov]

#syz upstream

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