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BUG: KCSAN: data-race in memcpy_and_pad / release_task

write to 0xffff88810375b648 of 8 bytes by task 13160 on cpu 1:
 __list_del include/linux/list.h:195 [inline]
 __list_del_entry include/linux/list.h:218 [inline]
 list_del_rcu include/linux/rculist.h:168 [inline]
 __unhash_process kernel/exit.c:149 [inline]
 __exit_signal kernel/exit.c:212 [inline]
 release_task+0x6f9/0xb60 kernel/exit.c:267
 wait_task_zombie kernel/exit.c:1264 [inline]
 wait_consider_task+0x114a/0x1660 kernel/exit.c:1491
 do_wait_pid kernel/exit.c:1630 [inline]
 __do_wait+0x34a/0x510 kernel/exit.c:1665
 do_wait+0xb7/0x260 kernel/exit.c:1706
 kernel_wait+0x51/0xc0 kernel/exit.c:1882
 call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
 call_usermodehelper_exec_work+0x9c/0x160 kernel/umh.c:163
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:463
 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 0xffff88810375b180 of 3264 bytes by task 13166 on cpu 0:
 memcpy_and_pad+0x48/0x80 lib/string_helpers.c:1007
 arch_dup_task_struct+0x2c/0x40 arch/x86/kernel/process.c:98
 dup_task_struct+0x83/0x6a0 kernel/fork.c:878
 copy_process+0x399/0x2000 kernel/fork.c:2004
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2605
 user_mode_thread+0x7d/0xb0 kernel/fork.c:2683
 call_usermodehelper_exec_sync kernel/umh.c:132 [inline]
 call_usermodehelper_exec_work+0x7a/0x160 kernel/umh.c:163
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 kernel/kthread.c:463
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 13166 Comm: kworker/u8:11 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_unbound call_usermodehelper_exec_work
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