[moderation] [fs?] KCSAN: data-race in __dentry_kill / d_set_d_op (18)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: afcd48134c58 Merge tag 'mm-hotfixes-stable-2024-06-26-17-2..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1159fd61980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e87b541dc1fc960
dashboard link: https://syzkaller.appspot.com/bug?extid=eb9586e8da0284754dfa
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/74d7d3ec21bb/disk-afcd4813.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fd49a4ae8fb1/vmlinux-afcd4813.xz
kernel image: https://storage.googleapis.com/syzbot-assets/57af65bdecc0/bzImage-afcd4813.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+eb9586...@syzkaller.appspotmail.com

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

read-write to 0xffff888100666600 of 4 bytes by task 3254 on cpu 1:
d_set_d_op+0x15b/0x1f0 fs/dcache.c:1796
simple_lookup+0x7c/0xa0 fs/libfs.c:79
lookup_open fs/namei.c:3483 [inline]
open_last_lookups fs/namei.c:3574 [inline]
path_openat+0xc85/0x1da0 fs/namei.c:3804
do_filp_open+0xf7/0x200 fs/namei.c:3834
do_sys_openat2+0xab/0x120 fs/open.c:1405
do_sys_open fs/open.c:1420 [inline]
__do_sys_openat fs/open.c:1436 [inline]
__se_sys_openat fs/open.c:1431 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1431
x64_sys_call+0x1057/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:258
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 0xffff888100666600 of 4 bytes by task 3345 on cpu 0:
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:3597 [inline]
path_openat+0x1118/0x1da0 fs/namei.c:3804
do_filp_open+0xf7/0x200 fs/namei.c:3834
do_sys_openat2+0xab/0x120 fs/open.c:1405
do_sys_open fs/open.c:1420 [inline]
__do_sys_openat fs/open.c:1436 [inline]
__se_sys_openat fs/open.c:1431 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1431
x64_sys_call+0x1057/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:258
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: 0x10000000 -> 0x00000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3345 Comm: udevd Not tainted 6.10.0-rc5-syzkaller-00035-gafcd48134c58 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================


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