syzbot

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BUG: KCSAN: data-race in __dentry_kill / fast_dput

write to 0xffff888106ab3310 of 8 bytes by task 12439 on cpu 0:
 __d_drop fs/dcache.c:566 [inline]
 __dentry_kill+0x142/0x4b0 fs/dcache.c:658
 dput+0x5e/0xd0 fs/dcache.c:902
 handle_mounts fs/namei.c:1640 [inline]
 step_into+0x5b2/0x820 fs/namei.c:1976
 open_last_lookups fs/namei.c:3827 [inline]
 path_openat+0x13e8/0x2170 fs/namei.c:4036
 do_filp_open+0x109/0x230 fs/namei.c:4066
 io_openat2+0x272/0x390 io_uring/openclose.c:140
 io_openat+0x1b/0x30 io_uring/openclose.c:177
 __io_issue_sqe+0xfb/0x2e0 io_uring/io_uring.c:1734
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1757
 io_wq_submit_work+0x3f7/0x5f0 io_uring/io_uring.c:1869
 io_worker_handle_work+0x46a/0x9f0 io_uring/io-wq.c:615
 io_wq_worker+0x22e/0x870 io_uring/io-wq.c:669
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888106ab3310 of 8 bytes by task 12430 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:359 [inline]
 retain_dentry fs/dcache.c:743 [inline]
 fast_dput+0x5f/0x2c0 fs/dcache.c:839
 dput+0x24/0xd0 fs/dcache.c:896
 handle_mounts fs/namei.c:1640 [inline]
 step_into+0x5b2/0x820 fs/namei.c:1976
 open_last_lookups fs/namei.c:3827 [inline]
 path_openat+0x13e8/0x2170 fs/namei.c:4036
 do_filp_open+0x109/0x230 fs/namei.c:4066
 io_openat2+0x272/0x390 io_uring/openclose.c:140
 io_openat+0x1b/0x30 io_uring/openclose.c:177
 __io_issue_sqe+0xfb/0x2e0 io_uring/io_uring.c:1734
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1757
 io_wq_submit_work+0x3f7/0x5f0 io_uring/io_uring.c:1869
 io_worker_handle_work+0x46a/0x9f0 io_uring/io-wq.c:615
 io_wq_worker+0x22e/0x870 io_uring/io-wq.c:669
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0xffff8882377f4dc8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12430 Comm: iou-wrk-12428 Not tainted 6.15.0-rc6-syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
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