audit: audit_backlog=65 > audit_backlog_limit=64 ================================================================== BUG: KCSAN: data-race in wq_worker_tick / wq_worker_tick read-write to 0xffff8881000c5ed8 of 8 bytes by interrupt on cpu 0: wq_worker_tick+0x60/0x230 kernel/workqueue.c:1493 sched_tick+0xda/0x210 kernel/sched/core.c:5585 update_process_times+0x15e/0x190 kernel/time/timer.c:2479 tick_sched_handle kernel/time/tick-sched.c:298 [inline] tick_nohz_handler+0x275/0x3d0 kernel/time/tick-sched.c:319 __run_hrtimer kernel/time/hrtimer.c:1785 [inline] __hrtimer_run_queues+0x218/0x4f0 kernel/time/hrtimer.c:1849 hrtimer_interrupt+0x269/0x810 kernel/time/hrtimer.c:1911 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x5f/0x1f0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 is_atomic kernel/kcsan/core.c:264 [inline] should_watch kernel/kcsan/core.c:277 [inline] check_access kernel/kcsan/core.c:752 [inline] __tsan_read_write4+0x136/0x180 kernel/kcsan/core.c:1024 nf_skip_egress include/linux/netfilter_netdev.h:137 [inline] __netif_receive_skb_core+0xd1f/0x1980 net/core/dev.c:6022 __netif_receive_skb_one_core net/core/dev.c:6162 [inline] __netif_receive_skb net/core/dev.c:6277 [inline] process_backlog+0x25b/0x670 net/core/dev.c:6628 __napi_poll+0x61/0x330 net/core/dev.c:7692 napi_poll net/core/dev.c:7755 [inline] net_rx_action+0x452/0x930 net/core/dev.c:7912 handle_softirqs+0xb9/0x2a0 kernel/softirq.c:622 do_softirq+0x45/0x60 kernel/softirq.c:523 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x658/0x690 net/core/skbuff.c:697 alloc_skb include/linux/skbuff.h:1383 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline] nsim_dev_trap_report_work+0x18a/0x630 drivers/net/netdevsim/dev.c:922 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0x4de/0x9e0 kernel/workqueue.c:3358 worker_thread+0x581/0x770 kernel/workqueue.c:3439 kthread+0x22a/0x280 kernel/kthread.c:436 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 read-write to 0xffff8881000c5ed8 of 8 bytes by interrupt on cpu 1: wq_worker_tick+0x60/0x230 kernel/workqueue.c:1493 sched_tick+0xda/0x210 kernel/sched/core.c:5585 update_process_times+0x15e/0x190 kernel/time/timer.c:2479 tick_sched_handle kernel/time/tick-sched.c:298 [inline] tick_nohz_handler+0x275/0x3d0 kernel/time/tick-sched.c:319 __run_hrtimer kernel/time/hrtimer.c:1785 [inline] __hrtimer_run_queues+0x218/0x4f0 kernel/time/hrtimer.c:1849 hrtimer_interrupt+0x269/0x810 kernel/time/hrtimer.c:1911 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x5f/0x1f0 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 arch_atomic64_read arch/x86/include/asm/atomic64_64.h:15 [inline] raw_atomic64_read include/linux/atomic/atomic-arch-fallback.h:2583 [inline] raw_atomic_long_read include/linux/atomic/atomic-long.h:38 [inline] atomic_long_read include/linux/atomic/atomic-instrumented.h:3189 [inline] find_watchpoint kernel/kcsan/core.c:131 [inline] check_access kernel/kcsan/core.c:737 [inline] __tsan_read_write8+0x2c/0x180 kernel/kcsan/core.c:1025 skb_push+0x2c/0x90 net/core/skbuff.c:2671 nf_bridge_push_encap_header include/net/netfilter/br_netfilter.h:37 [inline] br_nf_forward_finish+0x2a0/0x780 net/bridge/br_netfilter_hooks.c:660 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_forward_ip+0x5fe/0x620 net/bridge/br_netfilter_hooks.c:716 br_nf_forward+0x5a2/0xec0 net/bridge/br_netfilter_hooks.c:773 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0x78/0x180 net/netfilter/core.c:623 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK include/linux/netfilter.h:316 [inline] __br_forward+0x282/0x360 net/bridge/br_forward.c:115 deliver_clone net/bridge/br_forward.c:131 [inline] maybe_deliver net/bridge/br_forward.c:191 [inline] br_flood+0x451/0x6d0 net/bridge/br_forward.c:238 br_handle_frame_finish+0xdb8/0xfd0 net/bridge/br_input.c:229 br_nf_hook_thresh+0x233/0x270 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x550/0x580 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:318 [inline] br_nf_pre_routing_ipv6+0x1fa/0x2e0 net/bridge/br_netfilter_ipv6.c:184 br_nf_pre_routing+0x52b/0xbd0 net/bridge/br_netfilter_hooks.c:508 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x85f/0xa60 net/bridge/br_input.c:442 __netif_receive_skb_core+0x5b1/0x1980 net/core/dev.c:6051 __netif_receive_skb_one_core net/core/dev.c:6162 [inline] __netif_receive_skb net/core/dev.c:6277 [inline] process_backlog+0x25b/0x670 net/core/dev.c:6628 __napi_poll+0x61/0x330 net/core/dev.c:7692 napi_poll net/core/dev.c:7755 [inline] net_rx_action+0x452/0x930 net/core/dev.c:7912 handle_softirqs+0xb9/0x2a0 kernel/softirq.c:622 do_softirq+0x45/0x60 kernel/softirq.c:523 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:196 [inline] _raw_spin_unlock_bh+0x18/0x20 kernel/locking/spinlock.c:210 spin_unlock_bh include/linux/spinlock.h:395 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:891 [inline] nsim_dev_trap_report_work+0x52b/0x630 drivers/net/netdevsim/dev.c:922 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0x4de/0x9e0 kernel/workqueue.c:3358 worker_thread+0x581/0x770 kernel/workqueue.c:3439 kthread+0x22a/0x280 kernel/kthread.c:436 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 value changed: 0x000000000171df80 -> 0x0000000001720690 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 24748 Comm: kworker/u8:43 Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: events_unbound nsim_dev_trap_report_work ================================================================== audit: audit_backlog=65 > audit_backlog_limit=64 audit: audit_lost=3361 audit_rate_limit=0 audit_backlog_limit=64 audit: backlog limit exceeded audit: audit_backlog=65 > audit_backlog_limit=64 audit: audit_lost=3363 audit_rate_limit=0 audit_backlog_limit=64