syzbot

==================================================================
BUG: KCSAN: data-race in dput / vfs_rename

write to 0xffff888129a09780 of 4 bytes by task 7917 on cpu 1:
 dont_mount include/linux/dcache.h:352 [inline]
 vfs_rename+0x90a/0x10b0 fs/namei.c:4561
 do_renameat2+0x9e8/0xa50 fs/namei.c:4701
 __do_sys_rename fs/namei.c:4747 [inline]
 __se_sys_rename fs/namei.c:4745 [inline]
 __x64_sys_rename+0x44/0x60 fs/namei.c:4745
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888129a09780 of 4 bytes by task 4028 on cpu 0:
 fast_dput fs/dcache.c:727 [inline]
 dput+0x4b/0x700 fs/dcache.c:846
 __fput+0x28c/0x4f0 fs/file_table.c:293
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xf5/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x36e/0x390 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4028 Comm: udevd Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================