syzbot

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BUG: KCSAN: data-race in d_delete / step_into

write to 0xffff888106d7d180 of 4 bytes by task 27929 on cpu 0:
 d_delete+0x6e/0xa0 fs/dcache.c:2502
 vfs_unlink+0x3bc/0x3e0 fs/namei.c:4043
 do_unlinkat+0x29f/0x4f0 fs/namei.c:4096
 __do_sys_unlink fs/namei.c:4143 [inline]
 __se_sys_unlink fs/namei.c:4141 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4141
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888106d7d180 of 4 bytes by task 4839 on cpu 1:
 __follow_mount_rcu fs/namei.c:1398 [inline]
 handle_mounts fs/namei.c:1455 [inline]
 step_into+0xec/0xec0 fs/namei.c:1769
 walk_component+0x190/0x350 fs/namei.c:1945
 lookup_last fs/namei.c:2396 [inline]
 path_lookupat+0x12d/0x570 fs/namei.c:2420
 filename_lookup+0xf2/0x380 fs/namei.c:2453
 user_path_at_empty+0x3b/0x50 fs/namei.c:2733
 do_readlinkat+0x87/0x200 fs/stat.c:417
 __do_sys_readlink fs/stat.c:450 [inline]
 __se_sys_readlink fs/stat.c:447 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:447
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4839 Comm: systemd-udevd Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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