[moderation] [fs?] KCSAN: data-race in __dentry_kill / d_set_d_op (17)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4b6b51322118 Merge tag 'pwm/for-6.9-rc5-fixes' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17d3fec7180000
kernel config: https://syzkaller.appspot.com/x/.config?x=eaea34ec4c9b6fb6
dashboard link: https://syzkaller.appspot.com/bug?extid=7dd3b3e7fbec31b5e7cf
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/28de8300bba1/disk-4b6b5132.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/efa8d9244cf0/vmlinux-4b6b5132.xz
kernel image: https://storage.googleapis.com/syzbot-assets/57ed9778a935/bzImage-4b6b5132.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7dd3b3...@syzkaller.appspotmail.com

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

read-write to 0xffff88811981b840 of 4 bytes by task 4533 on cpu 0:
d_set_d_op+0x15b/0x1f0 fs/dcache.c:1796
simple_lookup+0x7c/0xa0 fs/libfs.c:79
lookup_open fs/namei.c:3475 [inline]
open_last_lookups fs/namei.c:3566 [inline]
path_openat+0xc85/0x1d80 fs/namei.c:3796
do_filp_open+0xf7/0x200 fs/namei.c:3826
do_sys_openat2+0xab/0x120 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1432
x64_sys_call+0x2cad/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:258
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811981b840 of 4 bytes by task 4510 on cpu 1:
dentry_unlist fs/dcache.c:573 [inline]
__dentry_kill+0x2a9/0x4b0 fs/dcache.c:617
dput+0x5c/0xd0 fs/dcache.c:845
handle_mounts fs/namei.c:1553 [inline]
step_into+0x21a/0x810 fs/namei.c:1842
open_last_lookups fs/namei.c:3589 [inline]
path_openat+0x10fc/0x1d80 fs/namei.c:3796
do_filp_open+0xf7/0x200 fs/namei.c:3826
do_sys_openat2+0xab/0x120 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1432
x64_sys_call+0x2cad/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:258
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x10000000 -> 0x00000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4510 Comm: udevd Not tainted 6.9.0-rc4-syzkaller-00034-g4b6b51322118 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================


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