syzbot

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BUG: KCSAN: data-race in __d_lookup / __d_rehash

write to 0xffff8881061676d0 of 8 bytes by task 10578 on cpu 1:
 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_open fs/namei.c:3470 [inline]
 open_last_lookups fs/namei.c:3560 [inline]
 path_openat+0xc4f/0x1d10 fs/namei.c:3790
 do_filp_open+0xf6/0x200 fs/namei.c:3820
 do_sys_openat2+0xab/0x110 fs/open.c:1407
 do_sys_open fs/open.c:1422 [inline]
 __do_sys_openat fs/open.c:1438 [inline]
 __se_sys_openat fs/open.c:1433 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1433
 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 0xffff8881061676d0 of 8 bytes by task 2767 on cpu 0:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:335 [inline]
 __d_lookup+0x10e/0x380 fs/dcache.c:2491
 lookup_fast+0x4c/0x290 fs/namei.c:1648
 walk_component fs/namei.c:1994 [inline]
 link_path_walk+0x3f4/0x7e0 fs/namei.c:2325
 path_lookupat+0x72/0x2a0 fs/namei.c:2478
 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: 0xffff888237ad9438 -> 0xffff888120030d88

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2767 Comm: udevd Not tainted 6.5.0-rc7-syzkaller-00104-g4f9e7fabf864 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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