==================================================================
BUG: KCSAN: data-race in kick_pool / wq_worker_running

read-write to 0xffff888237c2a8e4 of 4 bytes by task 9 on cpu 0:
 wq_worker_running+0x9b/0x120 kernel/workqueue.c:1434
 schedule_timeout+0xca/0x180 kernel/time/sleep_timeout.c:99
 schedule_timeout_uninterruptible kernel/time/sleep_timeout.c:158 [inline]
 msleep+0x4f/0x90 kernel/time/sleep_timeout.c:318
 nsim_fib4_rt_add drivers/net/netdevsim/fib.c:369 [inline]
 nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:432 [inline]
 nsim_fib4_event drivers/net/netdevsim/fib.c:464 [inline]
 nsim_fib_event+0x4996/0x4dc0 drivers/net/netdevsim/fib.c:884
 nsim_fib_event_work+0x133/0x200 drivers/net/netdevsim/fib.c:1493
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x4d4/0x9a0 kernel/workqueue.c:3405
 worker_thread+0x569/0x750 kernel/workqueue.c:3486
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888237c2a8e4 of 4 bytes by task 3296 on cpu 1:
 need_more_worker kernel/workqueue.c:952 [inline]
 kick_pool+0x49/0x2d0 kernel/workqueue.c:1274
 __queue_work+0x8e9/0xb90 kernel/workqueue.c:2402
 queue_work_on+0xa9/0x140 kernel/workqueue.c:2452
 queue_work include/linux/workqueue.h:699 [inline]
 schedule_work include/linux/workqueue.h:760 [inline]
 nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:-1 [inline]
 nsim_fib_event_nb+0xc3e/0xd90 drivers/net/netdevsim/fib.c:1043
 notifier_call_chain kernel/notifier.c:85 [inline]
 atomic_notifier_call_chain+0x79/0x1a0 kernel/notifier.c:223
 call_fib_notifiers+0x65/0xa0 net/core/fib_notifier.c:36
 call_fib4_notifiers+0x77/0xb0 net/ipv4/fib_notifier.c:27
 call_fib_entry_notifiers+0x113/0x140 net/ipv4/fib_trie.c:107
 fib_table_insert+0x8c1/0xee0 net/ipv4/fib_trie.c:1370
 fib_magic+0x213/0x270 net/ipv4/fib_frontend.c:1128
 fib_add_ifaddr+0xd0/0x310 net/ipv4/fib_frontend.c:1150
 fib_inetaddr_event+0xaf/0x1e0 net/ipv4/fib_frontend.c:1464
 notifier_call_chain kernel/notifier.c:85 [inline]
 blocking_notifier_call_chain+0x9b/0x1e0 kernel/notifier.c:380
 __inet_insert_ifa+0x4f3/0x5e0 net/ipv4/devinet.c:566
 inet_rtm_newaddr+0x97d/0xca0 net/ipv4/devinet.c:1001
 rtnetlink_rcv_msg+0x64b/0x720 net/core/rtnetlink.c:7076
 netlink_rcv_skb+0x11e/0x220 net/netlink/af_netlink.c:2556
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:7103
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x5a7/0x680 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x5be/0x6f0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x411/0x470 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0x76/0x90 net/socket.c:2255
 x64_sys_call+0x2d35/0x3020 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3296 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
==================================================================
8021q: adding VLAN 0 to HW filter on device batadv0
veth0_vlan: entered promiscuous mode
veth1_vlan: entered promiscuous mode
veth0_macvtap: entered promiscuous mode
veth1_macvtap: entered promiscuous mode
batman_adv: batadv0: Interface activated: batadv_slave_0
batman_adv: batadv0: Interface activated: batadv_slave_1
soft_limit_in_bytes is deprecated and will be removed. Please report your usecase to linux-mm@kvack.org if you depend on this functionality.