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BUG: KCSAN: data-race in memcpy_and_pad / rcu_tasks_trace_pregp_step

write to 0xffff8881016ec65c of 4 bytes by task 28 on cpu 1:
 rcu_tasks_trace_pertask_prep kernel/rcu/tasks.h:1784 [inline]
 rcu_tasks_trace_pregp_step+0x1b4/0x8f0 kernel/rcu/tasks.h:1828
 rcu_tasks_wait_gp+0x94/0x540 kernel/rcu/tasks.h:826
 rcu_tasks_one_gp+0x7f1/0x8e0 kernel/rcu/tasks.h:622
 rcu_tasks_kthread+0xf6/0x110 kernel/rcu/tasks.h:658
 kthread+0x488/0x510 kernel/kthread.c:463
 ret_from_fork+0x148/0x280 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff8881016ec200 of 3264 bytes by task 3039 on cpu 0:
 memcpy_and_pad+0x48/0x80 lib/string_helpers.c:1007
 arch_dup_task_struct+0x2c/0x40 arch/x86/kernel/process.c:108
 dup_task_struct+0x6e/0x940 kernel/fork.c:919
 copy_process+0x37e/0x1f10 kernel/fork.c:2052
 kernel_clone+0x16b/0x5b0 kernel/fork.c:2651
 __do_sys_clone kernel/fork.c:2792 [inline]
 __se_sys_clone kernel/fork.c:2776 [inline]
 __x64_sys_clone+0x143/0x180 kernel/fork.c:2776
 x64_sys_call+0x12d0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3039 Comm: dhcpcd 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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