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BUG: KCSAN: data-race in __dentry_kill / fast_dput

write to 0xffff88810044b0d0 of 8 bytes by task 5421 on cpu 0:
 __d_drop fs/dcache.c:575 [inline]
 __dentry_kill+0x142/0x4b0 fs/dcache.c:667
 dput+0x5e/0xd0 fs/dcache.c:911
 handle_mounts fs/namei.c:1640 [inline]
 step_into+0x5b2/0x820 fs/namei.c:1976
 walk_component fs/namei.c:2144 [inline]
 link_path_walk+0x571/0x900 fs/namei.c:2506
 path_openat+0x1de/0x2170 fs/namei.c:4042
 do_filp_open+0x109/0x230 fs/namei.c:4073
 io_openat2+0x272/0x390 io_uring/openclose.c:142
 io_openat+0x1b/0x30 io_uring/openclose.c:179
 __io_issue_sqe+0xfe/0x2e0 io_uring/io_uring.c:1730
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1753
 io_wq_submit_work+0x3f7/0x5f0 io_uring/io_uring.c:1865
 io_worker_handle_work+0x44e/0x9b0 io_uring/io-wq.c:642
 io_wq_worker+0x22e/0x870 io_uring/io-wq.c:696
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88810044b0d0 of 8 bytes by task 5417 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:752 [inline]
 fast_dput+0x5f/0x2c0 fs/dcache.c:848
 dput+0x24/0xd0 fs/dcache.c:905
 handle_mounts fs/namei.c:1640 [inline]
 step_into+0x5b2/0x820 fs/namei.c:1976
 walk_component fs/namei.c:2144 [inline]
 link_path_walk+0x571/0x900 fs/namei.c:2506
 path_openat+0x1de/0x2170 fs/namei.c:4042
 do_filp_open+0x109/0x230 fs/namei.c:4073
 io_openat2+0x272/0x390 io_uring/openclose.c:142
 io_openat+0x1b/0x30 io_uring/openclose.c:179
 __io_issue_sqe+0xfe/0x2e0 io_uring/io_uring.c:1730
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1753
 io_wq_submit_work+0x3f7/0x5f0 io_uring/io_uring.c:1865
 io_worker_handle_work+0x44e/0x9b0 io_uring/io-wq.c:642
 io_wq_worker+0x22e/0x870 io_uring/io-wq.c:696
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0xffff8882377e9da8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5417 Comm: iou-wrk-5403 Not tainted 6.15.0-syzkaller-02245-gdd3922cf9d4d #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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