bridge0: port 1(bridge_slave_0) entered blocking state
bridge0: port 1(bridge_slave_0) entered forwarding state
bridge0: port 2(bridge_slave_1) entered blocking state
bridge0: port 2(bridge_slave_1) entered forwarding state
==================================================================
BUG: KCSAN: data-race in copy_process / free_pid

read-write to 0xffffffff8685fc48 of 4 bytes by task 11512 on cpu 1:
 free_pid+0x77/0x180 kernel/pid.c:126
 free_pids+0x54/0xb0 kernel/pid.c:159
 release_task+0x9a9/0xb60 kernel/exit.c:296
 wait_task_zombie kernel/exit.c:1269 [inline]
 wait_consider_task+0x114a/0x1660 kernel/exit.c:1496
 do_wait_thread kernel/exit.c:1559 [inline]
 __do_wait+0xfa/0x510 kernel/exit.c:1677
 do_wait+0xb7/0x260 kernel/exit.c:1711
 kernel_wait4+0x16b/0x1e0 kernel/exit.c:1870
 __do_sys_wait4 kernel/exit.c:1898 [inline]
 __se_sys_wait4 kernel/exit.c:1894 [inline]
 __x64_sys_wait4+0x91/0x120 kernel/exit.c:1894
 x64_sys_call+0x2a66/0x2ff0 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 0xffffffff8685fc48 of 4 bytes by task 7899 on cpu 0:
 copy_process+0x14a6/0x2000 kernel/fork.c:2346
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2603
 user_mode_thread+0x7d/0xb0 kernel/fork.c:2681
 call_usermodehelper_exec_sync kernel/umh.c:132 [inline]
 call_usermodehelper_exec_work+0x7a/0x160 kernel/umh.c:163
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x489/0x510 kernel/kthread.c:464
 ret_from_fork+0xdd/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x8000010c -> 0x8000010b

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7899 Comm: kworker/u8:46 Tainted: G        W           6.16.0-syzkaller-11241-g186f3edfdd41 #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_unbound call_usermodehelper_exec_work
==================================================================