[moderation] [fs?] KCSAN: data-race in __dentry_kill / d_set_d_op (20)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bec7dcbc242c Merge tag 'probes-fixes-v6.14' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10034070580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a84f9483dff14ac4
dashboard link: https://syzkaller.appspot.com/bug?extid=b5cb423e9d7e50e94e92
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/e9f2db22d1d9/disk-bec7dcbc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7eea80f785b6/vmlinux-bec7dcbc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d13d39d44777/bzImage-bec7dcbc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b5cb42...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __dentry_kill / d_set_d_op

read-write to 0xffff88811726a6c0 of 4 bytes by task 9761 on cpu 0:
d_set_d_op+0x15b/0x1f0 fs/dcache.c:1852
simple_lookup+0x7c/0xa0 fs/libfs.c:79
lookup_open fs/namei.c:3644 [inline]
open_last_lookups fs/namei.c:3765 [inline]
path_openat+0xd76/0x2000 fs/namei.c:4001
do_filp_open+0x115/0x240 fs/namei.c:4031
do_sys_openat2+0xaa/0x110 fs/open.c:1429
do_sys_open fs/open.c:1444 [inline]
__do_sys_openat fs/open.c:1460 [inline]
__se_sys_openat fs/open.c:1455 [inline]
__x64_sys_openat+0xf8/0x120 fs/open.c:1455
x64_sys_call+0x1ac/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:258
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811726a6c0 of 4 bytes by task 9764 on cpu 1:
dentry_unlist fs/dcache.c:630 [inline]
__dentry_kill+0x2af/0x4c0 fs/dcache.c:674
dput+0x5c/0xd0 fs/dcache.c:902
handle_mounts fs/namei.c:1640 [inline]
step_into+0x226/0x860 fs/namei.c:1966
open_last_lookups fs/namei.c:3792 [inline]
path_openat+0x141f/0x2000 fs/namei.c:4001
do_filp_open+0x115/0x240 fs/namei.c:4031
do_sys_openat2+0xaa/0x110 fs/open.c:1429
do_sys_open fs/open.c:1444 [inline]
__do_sys_openat fs/open.c:1460 [inline]
__se_sys_openat fs/open.c:1455 [inline]
__x64_sys_openat+0xf8/0x120 fs/open.c:1455
x64_sys_call+0x1ac/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:258
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x01000000 -> 0x00000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 9764 Comm: syz.0.13610 Tainted: G W 6.15.0-rc1-syzkaller-00025-gbec7dcbc242c #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


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[syzbot]

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