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BUG: KCSAN: data-race in __dentry_kill / fast_dput

write to 0xffff88810635d790 of 8 bytes by task 6690 on cpu 0:
 __d_drop fs/dcache.c:549 [inline]
 __dentry_kill+0x13e/0x4c0 fs/dcache.c:641
 dput+0x5c/0xd0 fs/dcache.c:885
 handle_mounts fs/namei.c:1639 [inline]
 step_into+0x218/0x820 fs/namei.c:1952
 open_last_lookups fs/namei.c:3777 [inline]
 path_openat+0x13e5/0x1fc0 fs/namei.c:3986
 do_filp_open+0x107/0x230 fs/namei.c:4016
 io_openat2+0x280/0x3a0 io_uring/openclose.c:140
 io_openat+0x1a/0x30 io_uring/openclose.c:177
 io_issue_sqe+0x1a9/0xb70 io_uring/io_uring.c:1737
 io_wq_submit_work+0x3eb/0x540 io_uring/io_uring.c:1846
 io_worker_handle_work+0x486/0x9d0 io_uring/io-wq.c:601
 io_wq_worker+0x286/0x820 io_uring/io-wq.c:655
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff88810635d790 of 8 bytes by task 6685 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:366 [inline]
 retain_dentry fs/dcache.c:726 [inline]
 fast_dput+0x65/0x2c0 fs/dcache.c:822
 dput+0x24/0xd0 fs/dcache.c:879
 handle_mounts fs/namei.c:1639 [inline]
 step_into+0x218/0x820 fs/namei.c:1952
 open_last_lookups fs/namei.c:3777 [inline]
 path_openat+0x13e5/0x1fc0 fs/namei.c:3986
 do_filp_open+0x107/0x230 fs/namei.c:4016
 io_openat2+0x280/0x3a0 io_uring/openclose.c:140
 io_openat+0x1a/0x30 io_uring/openclose.c:177
 io_issue_sqe+0x1a9/0xb70 io_uring/io_uring.c:1737
 io_wq_submit_work+0x3eb/0x540 io_uring/io_uring.c:1846
 io_worker_handle_work+0x486/0x9d0 io_uring/io-wq.c:601
 io_wq_worker+0x286/0x820 io_uring/io-wq.c:655
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0xffff888237476230 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6685 Comm: iou-wrk-6684 Not tainted 6.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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