==================================================================
BUG: KCSAN: data-race in copy_process / free_pid

read-write to 0xffffffff8685fc68 of 4 bytes by task 19359 on cpu 0:
 free_pid+0x77/0x180 kernel/pid.c:126
 free_pids+0x7a/0xb0 kernel/pid.c:159
 release_task+0x9a9/0xb60 kernel/exit.c:295
 exit_notify kernel/exit.c:782 [inline]
 do_exit+0xd81/0x15c0 kernel/exit.c:976
 call_usermodehelper_exec_async+0x247/0x250 kernel/umh.c:122
 ret_from_fork+0xdd/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff8685fc68 of 4 bytes by task 5605 on cpu 1:
 copy_process+0x14a6/0x2000 kernel/fork.c:2342
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2599
 user_mode_thread+0x7d/0xb0 kernel/fork.c:2677
 call_usermodehelper_exec_work+0x41/0x160 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x486/0x510 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: 0x80000122 -> 0x80000121

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5605 Comm: kworker/u8:39 Tainted: G        W           6.16.0-syzkaller-08685-g260f6f4fda93 #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
==================================================================
dvmrp1 (unregistering): left allmulticast mode
bond0 (unregistering): (slave dummy0): Releasing backup interface
bond0 (unregistering): Released all slaves
tipc: Left network mode
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
pimreg (unregistering): left allmulticast mode
IPVS: stop unused estimator thread 0...
bridge_slave_1: left allmulticast mode
bridge_slave_1: left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
bridge_slave_0: left allmulticast mode
bridge_slave_0: left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
bridge_slave_1: left allmulticast mode
bridge_slave_1: left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
bridge_slave_0: left allmulticast mode
bridge_slave_0: left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
bridge_slave_1: left allmulticast mode
bridge_slave_1: left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
bridge_slave_0: left allmulticast mode
bridge_slave_0: left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
batman_adv: batadv0: Interface deactivated: gretap1
batman_adv: batadv0: Interface deactivated: gretap1
batman_adv: batadv0: Removing interface: gretap1

 (unregistering): (slave bond_slave_0): Releasing backup interface

 (unregistering): (slave bond_slave_1): Releasing backup interface

 (unregistering): Released all slaves
bond0 (unregistering): Released all slaves
batman_adv: batadv0: Removing interface: gretap1
bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
bond0 (unregistering): (slave dummy0): Releasing backup interface
bond0 (unregistering): Released all slaves
team0: Port device geneve1 removed
bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
bond0 (unregistering): (slave dummy0): Releasing backup interface
bond0 (unregistering): Released all slaves
bond1 (unregistering): Released all slaves
tipc: Left network mode
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
batman_adv: batadv0: Removing interface: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_1
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
batman_adv: batadv0: Removing interface: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_1
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
batman_adv: batadv0: Removing interface: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_1
team0 (unregistering): Port device team_slave_1 removed
team0 (unregistering): Port device team_slave_0 removed
team0 (unregistering): Port device team_slave_1 removed
team0 (unregistering): Port device team_slave_0 removed
IPVS: stop unused estimator thread 0...
IPVS: stop unused estimator thread 0...