syzbot

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BUG: KCSAN: data-race in lookup_fast / vfs_rmdir

write to 0xffff8880264bd480 of 4 bytes by task 21108 on cpu 0:
 dont_mount include/linux/dcache.h:357 [inline]
 vfs_rmdir+0x1ac/0x2a0 fs/namei.c:3905
 do_rmdir+0x186/0x310 fs/namei.c:3962
 __do_sys_rmdir fs/namei.c:3980 [inline]
 __se_sys_rmdir fs/namei.c:3978 [inline]
 __x64_sys_rmdir+0x2c/0x30 fs/namei.c:3978
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8880264bd480 of 4 bytes by task 21102 on cpu 1:
 d_revalidate fs/namei.c:822 [inline]
 lookup_fast+0x15f/0x350 fs/namei.c:1575
 walk_component+0x5c/0x350 fs/namei.c:1935
 link_path_walk+0x4ba/0x780 fs/namei.c:2262
 path_parentat fs/namei.c:2472 [inline]
 filename_parentat+0xf5/0x950 fs/namei.c:2494
 filename_create+0x58/0x3c0 fs/namei.c:3579
 user_path_create fs/namei.c:3654 [inline]
 do_symlinkat+0x6b/0x2b0 fs/namei.c:4196
 __do_sys_symlink fs/namei.c:4227 [inline]
 __se_sys_symlink fs/namei.c:4225 [inline]
 __x64_sys_symlink+0x32/0x40 fs/namei.c:4225
 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: 21102 Comm: systemd-udevd Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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