[moderation] [fs?] KCSAN: data-race in d_invalidate / fast_dput (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: eb5e56d14912 Merge tag 'platform-drivers-x86-v6.11-2' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=117f5ce5980000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb57e6ebf675f9d2
dashboard link: https://syzkaller.appspot.com/bug?extid=85f250a0680d314c55d6
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/bb722b67038f/disk-eb5e56d1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2d0a00127e52/vmlinux-eb5e56d1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b4fe5ac28731/bzImage-eb5e56d1.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+85f250...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in d_invalidate / fast_dput

write to 0xffff8881061f2cd0 of 8 bytes by task 2961 on cpu 0:
__d_drop fs/dcache.c:516 [inline]
d_invalidate+0x5c/0x1c0 fs/dcache.c:1592
lookup_fast+0x254/0x2a0 fs/namei.c:1683
walk_component fs/namei.c:2035 [inline]
link_path_walk+0x464/0x820 fs/namei.c:2404
path_openat+0x1aa/0x1f10 fs/namei.c:3882
do_filp_open+0xf7/0x200 fs/namei.c:3913
do_sys_openat2+0xab/0x120 fs/open.c:1416
do_sys_open fs/open.c:1431 [inline]
__do_sys_openat fs/open.c:1447 [inline]
__se_sys_openat fs/open.c:1442 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1442
x64_sys_call+0x1025/0x2d60 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 0xffff8881061f2cd0 of 8 bytes by task 3504 on cpu 1:
hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
d_unhashed include/linux/dcache.h:354 [inline]
retain_dentry fs/dcache.c:693 [inline]
fast_dput+0x65/0x2c0 fs/dcache.c:789
dput+0x24/0xd0 fs/dcache.c:846
handle_mounts fs/namei.c:1579 [inline]
step_into+0x21a/0x810 fs/namei.c:1877
walk_component fs/namei.c:2045 [inline]
link_path_walk+0x54c/0x820 fs/namei.c:2404
path_openat+0x1aa/0x1f10 fs/namei.c:3882
do_filp_open+0xf7/0x200 fs/namei.c:3913
do_sys_openat2+0xab/0x120 fs/open.c:1416
do_sys_open fs/open.c:1431 [inline]
__do_sys_openat fs/open.c:1447 [inline]
__se_sys_openat fs/open.c:1442 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1442
x64_sys_call+0x1025/0x2d60 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: 0xffff888237601068 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3504 Comm: udevd Not tainted 6.11.0-rc2-syzkaller-00011-geb5e56d14912 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
==================================================================


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[syzbot]

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