syzbot

==================================================================
BUG: KCSAN: data-race in memcpy_and_pad / rcu_tasks_trace_pregp_step

write to 0xffff88810a1d14dc 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+0x1ac/0x920 kernel/rcu/tasks.h:1828
 rcu_tasks_wait_gp+0x8b/0x530 kernel/rcu/tasks.h:826
 rcu_tasks_one_gp+0x7f6/0x8e0 kernel/rcu/tasks.h:622
 rcu_tasks_kthread+0xf7/0x110 kernel/rcu/tasks.h:658
 kthread+0x489/0x510 kernel/kthread.c:463
 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 0xffff88810a1d1080 of 3264 bytes by task 7589 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+0x83/0x690 kernel/fork.c:876
 copy_process+0x37d/0x1ef0 kernel/fork.c:2009
 create_io_thread+0x71/0xa0 kernel/fork.c:2556
 io_sq_offload_create+0x644/0x840 io_uring/sqpoll.c:517
 io_uring_create+0x2f2/0x4e0 io_uring/io_uring.c:3644
 io_uring_setup io_uring/io_uring.c:3715 [inline]
 __do_sys_io_uring_setup io_uring/io_uring.c:3749 [inline]
 __se_sys_io_uring_setup+0x1be/0x1d0 io_uring/io_uring.c:3740
 __x64_sys_io_uring_setup+0x31/0x40 io_uring/io_uring.c:3740
 x64_sys_call+0x244c/0x3000 arch/x86/include/generated/asm/syscalls_64.h:426
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2a0 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: 7589 Comm: syz.1.1468 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================