syzbot

==================================================================
BUG: KCSAN: data-race in __d_rehash / dput

write to 0xffff888106333490 of 8 bytes by task 5051 on cpu 0:
 hlist_bl_add_head_rcu include/linux/rculist_bl.h:81 [inline]
 __d_rehash+0xc4/0x220 fs/dcache.c:2579
 __d_add+0x36d/0x4a0 fs/dcache.c:2794
 d_add+0x45/0x50 fs/dcache.c:2817
 simple_lookup+0x89/0xa0 fs/libfs.c:76
 lookup_one_qstr_excl+0xc0/0x180 fs/namei.c:1605
 do_unlinkat+0x152/0x4f0 fs/namei.c:4381
 __do_sys_unlink fs/namei.c:4443 [inline]
 __se_sys_unlink fs/namei.c:4441 [inline]
 __x64_sys_unlink+0x30/0x40 fs/namei.c:4441
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888106333490 of 8 bytes by task 5052 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:335 [inline]
 fast_dput fs/dcache.c:837 [inline]
 dput+0xa8/0x1f0 fs/dcache.c:900
 handle_mounts fs/namei.c:1551 [inline]
 step_into+0x21a/0x800 fs/namei.c:1836
 walk_component+0x164/0x230 fs/namei.c:2004
 lookup_last fs/namei.c:2455 [inline]
 path_lookupat+0x10a/0x2a0 fs/namei.c:2479
 filename_lookup+0x126/0x300 fs/namei.c:2508
 vfs_statx+0xa9/0x300 fs/stat.c:238
 vfs_fstatat fs/stat.c:276 [inline]
 __do_sys_newfstatat fs/stat.c:446 [inline]
 __se_sys_newfstatat+0x8a/0x2a0 fs/stat.c:440
 __x64_sys_newfstatat+0x55/0x60 fs/stat.c:440
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0xffff88823764a168 -> 0xffff888109ae2488

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5052 Comm: udevd Not tainted 6.4.0-syzkaller-01224-g1ef6663a587b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
==================================================================