[moderation] [fs?] KCSAN: data-race in link_path_walk / shrink_dentry_list (10)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6bc40e44f1dd Merge tag 'ovl-fixes-6.7-rc2' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10c28c58e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=a91f789b98394377
dashboard link: https://syzkaller.appspot.com/bug?extid=99a8d5e57fe3d6ecb61a
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org 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/4c54159bb579/disk-6bc40e44.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3a252c242f68/vmlinux-6bc40e44.xz
kernel image: https://storage.googleapis.com/syzbot-assets/235f427df017/bzImage-6bc40e44.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+99a8d5...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in link_path_walk / shrink_dentry_list

read-write to 0xffff88812a403240 of 4 bytes by task 32024 on cpu 1:
d_shrink_del fs/dcache.c:448 [inline]
shrink_dentry_list+0x1c7/0x380 fs/dcache.c:1188
shrink_dcache_sb+0x165/0x290 fs/dcache.c:1321
reconfigure_super+0x3ef/0x580 fs/super.c:1121
do_remount fs/namespace.c:2884 [inline]
path_mount+0x969/0xb30 fs/namespace.c:3656
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount+0x27f/0x2d0 fs/namespace.c:3863
__x64_sys_mount+0x67/0x80 fs/namespace.c:3863
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88812a403240 of 4 bytes by task 17236 on cpu 0:
__d_entry_type include/linux/dcache.h:386 [inline]
d_can_lookup include/linux/dcache.h:401 [inline]
link_path_walk+0x4fc/0x7e0 fs/namei.c:2339
path_lookupat+0x72/0x2a0 fs/namei.c:2482
filename_lookup+0x126/0x300 fs/namei.c:2512
vfs_statx+0xa2/0x430 fs/stat.c:240
vfs_fstatat+0xcd/0x100 fs/stat.c:295
__do_sys_newfstatat fs/stat.c:459 [inline]
__se_sys_newfstatat+0x58/0x260 fs/stat.c:453
__x64_sys_newfstatat+0x55/0x60 fs/stat.c:453
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00280400 -> 0x00200000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17236 Comm: syz-executor.1 Tainted: G W 6.7.0-rc1-syzkaller-00139-g6bc40e44f1dd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================


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[syzbot]

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