syzbot

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BUG: KCSAN: data-race in __d_lookup_rcu / __d_rehash

read to 0xffff8881636eb850 of 8 bytes by task 6795 on cpu 0:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:342 [inline]
 __d_lookup_rcu+0x120/0x290 fs/dcache.c:2224
 lookup_fast+0x8e/0x290 fs/namei.c:1628
 walk_component+0x3f/0x230 fs/namei.c:2001
 lookup_last fs/namei.c:2462 [inline]
 path_lookupat+0x10a/0x2a0 fs/namei.c:2486
 filename_lookup+0x126/0x300 fs/namei.c:2515
 vfs_statx+0xa2/0x320 fs/stat.c:244
 vfs_fstatat+0xcd/0x100 fs/stat.c:304
 __do_sys_newfstatat fs/stat.c:468 [inline]
 __se_sys_newfstatat+0x58/0x260 fs/stat.c:462
 __x64_sys_newfstatat+0x55/0x60 fs/stat.c:462
 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

write to 0xffff8881636eb850 of 8 bytes by task 2774 on cpu 1:
 hlist_bl_add_head_rcu include/linux/rculist_bl.h:81 [inline]
 __d_rehash+0xc4/0x220 fs/dcache.c:2403
 __d_add+0x36d/0x4a0 fs/dcache.c:2618
 d_add+0x45/0x50 fs/dcache.c:2641
 simple_lookup+0x89/0xa0 fs/libfs.c:79
 lookup_one_qstr_excl+0xc0/0x180 fs/namei.c:1608
 do_unlinkat+0x144/0x4c0 fs/namei.c:4390
 __do_sys_unlink fs/namei.c:4450 [inline]
 __se_sys_unlink fs/namei.c:4448 [inline]
 __x64_sys_unlink+0x30/0x40 fs/namei.c:4448
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2774 Comm: udevd Not tainted 6.8.0-rc6-syzkaller-00120-g87adedeba51a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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