syzbot

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BUG: KCSAN: data-race in lookup_fast / vfs_rename

write to 0xffff88810d861b40 of 4 bytes by task 20702 on cpu 0:
 dont_mount include/linux/dcache.h:355 [inline]
 vfs_rename+0xd0f/0xe60 fs/namei.c:4322
 do_renameat2+0x5c3/0x900 fs/namei.c:4457
 __do_sys_rename fs/namei.c:4508 [inline]
 __se_sys_rename fs/namei.c:4506 [inline]
 __x64_sys_rename+0x58/0x60 fs/namei.c:4506
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d861b40 of 4 bytes by task 4878 on cpu 1:
 d_revalidate fs/namei.c:767 [inline]
 lookup_fast+0x15f/0x370 fs/namei.c:1493
 open_last_lookups fs/namei.c:3146 [inline]
 path_openat+0x45e/0x20a0 fs/namei.c:3368
 do_filp_open+0xbd/0x1d0 fs/namei.c:3398
 do_sys_openat2+0xa3/0x250 fs/open.c:1172
 do_sys_open fs/open.c:1188 [inline]
 __do_sys_open fs/open.c:1196 [inline]
 __se_sys_open fs/open.c:1192 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1192
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4878 Comm: systemd-udevd Not tainted 5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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