syzbot

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BUG: KCSAN: data-race in dput / vfs_rename

write to 0xffff8881252ac600 of 4 bytes by task 18348 on cpu 0:
 dont_mount include/linux/dcache.h:352 [inline]
 vfs_rename+0x90a/0x10b0 fs/namei.c:4479
 do_renameat2+0x9e3/0xa50 fs/namei.c:4619
 __do_sys_rename fs/namei.c:4665 [inline]
 __se_sys_rename fs/namei.c:4663 [inline]
 __x64_sys_rename+0x47/0x60 fs/namei.c:4663
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881252ac600 of 4 bytes by task 3903 on cpu 1:
 fast_dput fs/dcache.c:727 [inline]
 dput+0x4d/0x750 fs/dcache.c:846
 path_put fs/namei.c:482 [inline]
 terminate_walk+0x107/0x250 fs/namei.c:596
 path_openat+0xfff/0x36e0 fs/namei.c:3529
 do_filp_open+0x11e/0x1b0 fs/namei.c:3555
 do_sys_open+0x3b3/0x4f0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x55/0x70 fs/open.c:1110
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3903 Comm: udevd Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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