syzbot

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BUG: KCSAN: data-race in memcpy_and_pad / release_task

write to 0xffff888103356648 of 8 bytes by task 6974 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:148 [inline]
 __exit_signal kernel/exit.c:211 [inline]
 release_task+0x6f9/0xb60 kernel/exit.c:266
 wait_task_zombie kernel/exit.c:1267 [inline]
 wait_consider_task+0x113f/0x1650 kernel/exit.c:1494
 do_wait_thread kernel/exit.c:1557 [inline]
 __do_wait+0xfa/0x510 kernel/exit.c:1675
 do_wait+0xb7/0x260 kernel/exit.c:1709
 kernel_wait4+0x16b/0x1e0 kernel/exit.c:1868
 __do_sys_wait4 kernel/exit.c:1896 [inline]
 __se_sys_wait4 kernel/exit.c:1892 [inline]
 __x64_sys_wait4+0x91/0x120 kernel/exit.c:1892
 x64_sys_call+0x26c8/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:62
 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

read to 0xffff888103356180 of 3200 bytes by task 9200 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:873
 copy_process+0x399/0x1f90 kernel/fork.c:1999
 kernel_clone+0x16c/0x5b0 kernel/fork.c:2599
 __do_sys_clone3 kernel/fork.c:2903 [inline]
 __se_sys_clone3+0x1c2/0x200 kernel/fork.c:2882
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:2882
 x64_sys_call+0x10c9/0x2fb0 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: 9200 Comm: syz.5.1941 Not tainted 6.16.0-rc7-syzkaller-00140-gec2df4364666 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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