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BUG: KCSAN: data-race in __dentry_kill / fast_dput

write to 0xffff888167060910 of 8 bytes by task 15809 on cpu 0:
 __d_drop fs/dcache.c:576 [inline]
 __dentry_kill+0x142/0x4b0 fs/dcache.c:668
 finish_dput+0x2b/0x200 fs/dcache.c:879
 dput+0x52/0x60 fs/dcache.c:928
 handle_mounts fs/namei.c:1690 [inline]
 step_into_slowpath+0x36b/0x480 fs/namei.c:2043
 step_into fs/namei.c:2091 [inline]
 walk_component fs/namei.c:2227 [inline]
 link_path_walk+0x974/0xe30 fs/namei.c:2589
 path_openat+0x1c0/0x23b0 fs/namei.c:4783
 do_filp_open+0x1f1/0x230 fs/namei.c:4816
 io_openat2+0x272/0x390 io_uring/openclose.c:143
 io_openat+0x1b/0x30 io_uring/openclose.c:180
 __io_issue_sqe+0xfe/0x2e0 io_uring/io_uring.c:1792
 io_issue_sqe+0x56/0xa80 io_uring/io_uring.c:1815
 io_wq_submit_work+0x3f7/0x5f0 io_uring/io_uring.c:1927
 io_worker_handle_work+0x44e/0x9b0 io_uring/io-wq.c:650
 io_wq_worker+0x22e/0x860 io_uring/io-wq.c:704
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff888167060910 of 8 bytes by task 15808 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:753 [inline]
 fast_dput+0x5f/0x2c0 fs/dcache.c:849
 dput+0x24/0x60 fs/dcache.c:924
 handle_mounts fs/namei.c:1690 [inline]
 step_into_slowpath+0x36b/0x480 fs/namei.c:2043
 step_into fs/namei.c:2091 [inline]
 walk_component fs/namei.c:2227 [inline]
 link_path_walk+0x974/0xe30 fs/namei.c:2589
 path_openat+0x1c0/0x23b0 fs/namei.c:4783
 do_filp_open+0x109/0x230 fs/namei.c:4814
 io_openat2+0x272/0x390 io_uring/openclose.c:143
 io_openat+0x1b/0x30 io_uring/openclose.c:180
 __io_issue_sqe+0xfe/0x2e0 io_uring/io_uring.c:1792
 io_issue_sqe+0x56/0xa80 io_uring/io_uring.c:1815
 io_queue_sqe io_uring/io_uring.c:2042 [inline]
 io_submit_sqe io_uring/io_uring.c:2320 [inline]
 io_submit_sqes+0x78b/0x11b0 io_uring/io_uring.c:2434
 __do_sys_io_uring_enter io_uring/io_uring.c:3280 [inline]
 __se_sys_io_uring_enter+0x1bd/0x1a30 io_uring/io_uring.c:3219
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3219
 x64_sys_call+0x27e4/0x3000 arch/x86/include/generated/asm/syscalls_64.h:427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff8882377edc50 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15808 Comm: syz.0.24035 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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