syzbot

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BUG: KCSAN: data-race in dput / vfs_rmdir

write to 0xffff8880304a7300 of 4 bytes by task 4975 on cpu 1:
 dont_mount include/linux/dcache.h:355 [inline]
 vfs_rmdir+0x1a6/0x2a0 fs/namei.c:3721
 do_rmdir+0x16e/0x300 fs/namei.c:3776
 __do_sys_rmdir fs/namei.c:3794 [inline]
 __se_sys_rmdir fs/namei.c:3792 [inline]
 __x64_sys_rmdir+0x2c/0x30 fs/namei.c:3792
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880304a7300 of 4 bytes by task 4976 on cpu 0:
 fast_dput fs/dcache.c:746 [inline]
 dput+0x2f/0x420 fs/dcache.c:872
 handle_mounts fs/namei.c:1389 [inline]
 step_into+0x444/0xeb0 fs/namei.c:1691
 walk_component+0x190/0x350 fs/namei.c:1867
 lookup_last fs/namei.c:2312 [inline]
 path_lookupat+0x12d/0x560 fs/namei.c:2336
 filename_lookup+0xf2/0x380 fs/namei.c:2369
 user_path_at_empty+0x3b/0x50 fs/namei.c:2649
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x98/0x290 fs/stat.c:185
 vfs_fstatat fs/stat.c:207 [inline]
 vfs_lstat include/linux/fs.h:3122 [inline]
 __do_sys_newlstat fs/stat.c:362 [inline]
 __se_sys_newlstat+0x46/0x250 fs/stat.c:356
 __x64_sys_newlstat+0x2d/0x40 fs/stat.c:356
 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: 0 PID: 4976 Comm: systemd-udevd Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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