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BUG: KCSAN: data-race in copy_process / free_pid

read-write to 0xffffffff86e5c368 of 4 bytes by task 26955 on cpu 0:
 free_pid+0xb3/0x1b0 kernel/pid.c:124
 free_pids+0x7a/0xb0 kernel/pid.c:156
 release_task+0xa28/0xb90 kernel/exit.c:302
 wait_task_zombie kernel/exit.c:1291 [inline]
 wait_consider_task+0x10ef/0x15f0 kernel/exit.c:1518
 do_wait_thread kernel/exit.c:1581 [inline]
 __do_wait+0xf1/0x500 kernel/exit.c:1699
 do_wait+0xb6/0x230 kernel/exit.c:1733
 kernel_wait4+0x19f/0x210 kernel/exit.c:1892
 __do_sys_wait4 kernel/exit.c:1920 [inline]
 __se_sys_wait4 kernel/exit.c:1916 [inline]
 __x64_sys_wait4+0x91/0x120 kernel/exit.c:1916
 x64_sys_call+0x108f/0x2550 arch/x86/include/generated/asm/syscalls_64.h:62
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86e5c368 of 4 bytes by task 26957 on cpu 1:
 copy_process+0x1ae8/0x2360 kernel/fork.c:2490
 kernel_clone+0x1c0/0x5f0 kernel/fork.c:2771
 __do_sys_clone kernel/fork.c:2913 [inline]
 __se_sys_clone kernel/fork.c:2897 [inline]
 __x64_sys_clone+0x143/0x180 kernel/fork.c:2897
 x64_sys_call+0x2479/0x2550 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x800000ac -> 0x800000ab

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 26957 Comm: syz-executor425 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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