KCSAN: data-race in memcpy_and_pad / trc_wait_for_one

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in memcpy_and_pad / trc_wait_for_one_reader kernel	6				1	105d	105d	0/29	auto-obsoleted due to no activity on 2025/11/17 20:45

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BUG: KCSAN: data-race in memcpy_and_pad / trc_wait_for_one_reader

write to 0xffff888161dc845c of 4 bytes by task 28 on cpu 1:
 trc_wait_for_one_reader+0x283/0x380 kernel/rcu/tasks.h:1756
 check_all_holdout_tasks_trace+0xcb/0x4b0 kernel/rcu/tasks.h:1946
 rcu_tasks_wait_gp+0x3fd/0x530 kernel/rcu/tasks.h:885
 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 0xffff888161dc8000 of 3264 bytes by task 19119 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/0x950 kernel/fork.c:919
 copy_process+0x37d/0x1ef0 kernel/fork.c:2052
 create_io_thread+0x71/0xa0 kernel/fork.c:2599
 create_io_worker+0xdf/0x360 io_uring/io-wq.c:911
 io_wq_create_worker io_uring/io-wq.c:339 [inline]
 io_wq_enqueue+0x2c1/0x3a0 io_uring/io-wq.c:1038
 io_queue_iowq+0x208/0x2f0 io_uring/io_uring.c:491
 io_req_task_submit+0x69/0xa0 io_uring/io_uring.c:1432
 __io_run_local_work_loop io_uring/io_uring.c:1344 [inline]
 __io_run_local_work+0x2ea/0x580 io_uring/io_uring.c:1378
 io_run_local_work_locked+0x5a/0x70 io_uring/io_uring.c:1400
 __do_sys_io_uring_enter io_uring/io_uring.c:3293 [inline]
 __se_sys_io_uring_enter+0xd71/0x1a30 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+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 60928 PID: 19119 Comm: syz.3.16886 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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