[moderation] [fs?] KCSAN: data-race in __dentry_kill / lookup_fast (10)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1c892cdd8fe0 Merge tag 'vfs-6.8-rc6.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11c741c2180000
kernel config: https://syzkaller.appspot.com/x/.config?x=7507056e4ee79a
dashboard link: https://syzkaller.appspot.com/bug?extid=249744a471c6ea990403
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/139c3c1075e8/disk-1c892cdd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/84baf552e6fb/vmlinux-1c892cdd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bec5bd9af52d/bzImage-1c892cdd.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+249744...@syzkaller.appspotmail.com

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

read-write to 0xffff88813f8c8cc0 of 4 bytes by task 21662 on cpu 0:
dentry_unlist fs/dcache.c:548 [inline]
__dentry_kill+0x21c/0x4a0 fs/dcache.c:617
dput+0x54/0xc0 fs/dcache.c:845
do_renameat2+0x7d8/0xa60 fs/namei.c:5038
__do_sys_rename fs/namei.c:5083 [inline]
__se_sys_rename fs/namei.c:5081 [inline]
__x64_sys_rename+0x5c/0x70 fs/namei.c:5081
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+0x63/0x6b

read to 0xffff88813f8c8cc0 of 4 bytes by task 19993 on cpu 1:
d_revalidate fs/namei.c:861 [inline]
lookup_fast+0xd9/0x290 fs/namei.c:1642
open_last_lookups fs/namei.c:3533 [inline]
path_openat+0x446/0x1d40 fs/namei.c:3795
do_filp_open+0xf6/0x200 fs/namei.c:3825
do_sys_openat2+0xab/0x110 fs/open.c:1404
do_sys_open fs/open.c:1419 [inline]
__do_sys_openat fs/open.c:1435 [inline]
__se_sys_openat fs/open.c:1430 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1430
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+0x63/0x6b

value changed: 0x00400108 -> 0x00008108

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19993 Comm: udevd Not tainted 6.8.0-rc5-syzkaller-00121-g1c892cdd8fe0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================
I/O error, dev loop2, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0


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