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 (2) kernel	6				2	202d	242d	0/29	auto-obsoleted due to no activity on 2026/03/23 12:24

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BUG: KCSAN: data-race in memcpy_and_pad / trc_wait_for_one_reader

write to 0xffff88810ac2465c of 4 bytes by task 28 on cpu 1:
 trc_wait_for_one_reader+0x283/0x3c0 kernel/rcu/tasks.h:1756
 check_all_holdout_tasks_trace+0xcb/0x4b0 kernel/rcu/tasks.h:1946
 rcu_tasks_wait_gp+0x3fa/0x530 kernel/rcu/tasks.h:885
 rcu_tasks_one_gp+0x7f3/0x8e0 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+0x11f/0x1b0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff88810ac24200 of 3264 bytes by task 8419 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:877
 copy_process+0x399/0x2000 kernel/fork.c:2004
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2605
 __do_sys_clone3 kernel/fork.c:2909 [inline]
 __se_sys_clone3+0x1c2/0x200 kernel/fork.c:2888
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:2888
 x64_sys_call+0x1fc9/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:436
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 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: 8419 Comm: syz.3.1619 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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