syzbot

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BUG: KCSAN: data-race in d_delete / lookup_fast

write to 0xffff888106bfb480 of 4 bytes by task 5695 on cpu 0:
 d_delete+0x6e/0xe0 fs/dcache.c:2504
 vfs_unlink+0x3d8/0x400 fs/namei.c:4039
 do_unlinkat+0x238/0x4f0 fs/namei.c:4092
 __do_sys_unlink fs/namei.c:4139 [inline]
 __se_sys_unlink fs/namei.c:4137 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4137
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888106bfb480 of 4 bytes by task 1037 on cpu 1:
 d_revalidate fs/namei.c:826 [inline]
 lookup_fast+0x15f/0x350 fs/namei.c:1578
 walk_component+0x5c/0x350 fs/namei.c:1938
 lookup_last fs/namei.c:2397 [inline]
 path_lookupat+0x12d/0x570 fs/namei.c:2421
 filename_lookup+0xff/0x390 fs/namei.c:2454
 user_path_at_empty+0x3b/0x50 fs/namei.c:2734
 do_readlinkat+0x87/0x200 fs/stat.c:425
 __do_sys_readlink fs/stat.c:458 [inline]
 __se_sys_readlink fs/stat.c:455 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:455
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00600108 -> 0x00008008

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1037 Comm: systemd-udevd Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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