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BUG: KCSAN: data-race in __dentry_kill / fast_dput

write to 0xffff88810045f790 of 8 bytes by task 21366 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:1967
 walk_component+0x162/0x220 fs/namei.c:2135
 lookup_last fs/namei.c:2630 [inline]
 path_lookupat+0xfe/0x2a0 fs/namei.c:2654
 do_o_path+0x45/0x130 fs/namei.c:4017
 path_openat+0x1df9/0x2170 fs/namei.c:4039
 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:1773
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1796
 io_wq_submit_work+0x3f7/0x5f0 io_uring/io_uring.c:1908
 io_worker_handle_work+0x44e/0x9b0 io_uring/io-wq.c:650
 io_wq_worker+0x22e/0x870 io_uring/io-wq.c:704
 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 0xffff88810045f790 of 8 bytes by task 21375 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:361 [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:1967
 walk_component+0x162/0x220 fs/namei.c:2135
 lookup_last fs/namei.c:2630 [inline]
 path_lookupat+0xfe/0x2a0 fs/namei.c:2654
 do_o_path+0x45/0x130 fs/namei.c:4017
 path_openat+0x1df9/0x2170 fs/namei.c:4039
 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:1773
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1796
 io_wq_submit_work+0x3f7/0x5f0 io_uring/io_uring.c:1908
 io_worker_handle_work+0x44e/0x9b0 io_uring/io-wq.c:650
 io_wq_worker+0x22e/0x870 io_uring/io-wq.c:704
 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: 0xffff888237903c58 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 21375 Comm: iou-wrk-21358 Not tainted 6.17.0-rc1-syzkaller-00199-gdfd4b508c8c6 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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