[moderation] [fs?] KCSAN: data-race in drop_nlink / generic_fillattr (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3d5ad2d4eca3 Merge tag 'bpf-fixes' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15b4fc5f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=fd83253b74c9c570
dashboard link: https://syzkaller.appspot.com/bug?extid=f88da83995d0edba3126
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9d112e37e26b/disk-3d5ad2d4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d8f036bdcdb7/vmlinux-3d5ad2d4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/61727d52db48/bzImage-3d5ad2d4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f88da8...@syzkaller.appspotmail.com

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

write to 0xffff888111928698 of 4 bytes by task 3260 on cpu 1:
drop_nlink+0x3b/0x90 fs/inode.c:337
shmem_unlink+0x163/0x180 mm/shmem.c:3696
vfs_unlink+0x275/0x430 fs/namei.c:4469
do_unlinkat+0x236/0x4c0 fs/namei.c:4533
__do_sys_unlink fs/namei.c:4581 [inline]
__se_sys_unlink fs/namei.c:4579 [inline]
__x64_sys_unlink+0x2e/0x40 fs/namei.c:4579
x64_sys_call+0x280f/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:88
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888111928698 of 4 bytes by task 3262 on cpu 0:
generic_fillattr+0xf8/0x2f0 fs/stat.c:55
shmem_getattr+0x17b/0x200 mm/shmem.c:1169
vfs_getattr_nosec fs/stat.c:166 [inline]
vfs_getattr+0x19b/0x1e0 fs/stat.c:207
vfs_statx_path fs/stat.c:251 [inline]
vfs_statx+0x134/0x2f0 fs/stat.c:315
vfs_fstatat+0xec/0x110 fs/stat.c:341
__do_sys_newfstatat fs/stat.c:505 [inline]
__se_sys_newfstatat+0x58/0x260 fs/stat.c:499
__x64_sys_newfstatat+0x55/0x70 fs/stat.c:499
x64_sys_call+0x141f/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:263
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3262 Comm: udevd Tainted: G W 6.12.0-rc3-syzkaller-00389-g3d5ad2d4eca3 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


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[syzbot]

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