[moderation] [fs?] KCSAN: data-race in drop_nlink / generic_fillattr (9)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 243f750a2df0 Merge tag 'gpio-fixes-for-v6.13-rc3' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=112dad44580000
kernel config: https://syzkaller.appspot.com/x/.config?x=1fe4854f351e948c
dashboard link: https://syzkaller.appspot.com/bug?extid=9641ae66a73e90af8f25
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/2125b9ae9a18/disk-243f750a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7227f9bc5863/vmlinux-243f750a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/85211c812635/bzImage-243f750a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9641ae...@syzkaller.appspotmail.com

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

write to 0xffff8881188c6f48 of 4 bytes by task 13944 on cpu 1:
drop_nlink+0x3b/0x90 fs/inode.c:408
shmem_unlink+0x154/0x170 mm/shmem.c:3806
vfs_unlink+0x275/0x430 fs/namei.c:4523
do_unlinkat+0x237/0x4d0 fs/namei.c:4587
__do_sys_unlink fs/namei.c:4635 [inline]
__se_sys_unlink fs/namei.c:4633 [inline]
__x64_sys_unlink+0x2e/0x40 fs/namei.c:4633
x64_sys_call+0x2329/0x2dc0 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 0xffff8881188c6f48 of 4 bytes by task 14765 on cpu 0:
generic_fillattr+0xf8/0x330 fs/stat.c:91
shmem_getattr+0x17b/0x200 mm/shmem.c:1177
vfs_getattr_nosec fs/stat.c:208 [inline]
vfs_getattr fs/stat.c:246 [inline]
vfs_statx_path+0x171/0x2d0 fs/stat.c:283
vfs_statx+0xe1/0x170 fs/stat.c:347
vfs_fstatat fs/stat.c:366 [inline]
__do_sys_newfstatat fs/stat.c:530 [inline]
__se_sys_newfstatat+0xdc/0x300 fs/stat.c:524
__x64_sys_newfstatat+0x55/0x70 fs/stat.c:524
x64_sys_call+0x236d/0x2dc0 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: 14765 Comm: udevd Not tainted 6.13.0-rc2-syzkaller-00192-g243f750a2df0 #0
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.