syzbot

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BUG: KCSAN: data-race in __d_drop / __d_lookup_rcu

read to 0xffff888104645610 of 8 bytes by task 7394 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:332 [inline]
 __d_lookup_rcu+0x12f/0x400 fs/dcache.c:2347
 lookup_fast+0xc1/0x360 fs/namei.c:1630
 open_last_lookups fs/namei.c:3369 [inline]
 path_openat+0x488/0x1f30 fs/namei.c:3606
 do_filp_open+0x105/0x220 fs/namei.c:3636
 io_openat2+0x38d/0x780 fs/io_uring.c:4400
 io_issue_sqe+0x169a/0x9610
 __io_queue_sqe+0x20/0x6a0 fs/io_uring.c:7098
 io_queue_sqe+0x46/0x550 fs/io_uring.c:7140
 io_submit_sqe+0x796/0x4b34 fs/io_uring.c:7348
 io_submit_sqes+0x25f/0x560 fs/io_uring.c:7454
 __do_sys_io_uring_enter fs/io_uring.c:10162 [inline]
 __se_sys_io_uring_enter+0x212/0xb00 fs/io_uring.c:10104
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:10104
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff888104645610 of 8 bytes by task 7403 on cpu 0:
 __d_drop+0x16a/0x250 fs/dcache.c:508
 __dentry_kill+0x12f/0x450 fs/dcache.c:602
 dput+0x218/0x430 fs/dcache.c:913
 handle_mounts fs/namei.c:1552 [inline]
 step_into+0x468/0xf70 fs/namei.c:1850
 open_last_lookups fs/namei.c:3423 [inline]
 path_openat+0xfa5/0x1f30 fs/namei.c:3606
 do_filp_open+0x105/0x220 fs/namei.c:3636
 io_openat2+0x38d/0x780 fs/io_uring.c:4400
 io_issue_sqe+0x169a/0x9610
 io_wq_submit_work+0x1c5/0x370 fs/io_uring.c:6916
 io_worker_handle_work+0x51b/0xc10 fs/io-wq.c:588
 io_wqe_worker+0x1bc/0x4f0 fs/io-wq.c:639
 ret_from_fork+0x1f/0x30

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7403 Comm: iou-wrk-7398 Not tainted 5.17.0-rc8-syzkaller-00061-g34e047aa16c0-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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