================================================================== 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+0x64/0x240 kernel/workqueue.c:1493 sched_tick+0xbc/0x1f0 kernel/sched/core.c:5672 update_process_times+0x15e/0x190 kernel/time/timer.c:2480 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:1930 [inline] __hrtimer_run_queues+0x276/0x4f0 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x261/0x850 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 __tsan_unaligned_volatile_write4+0x0/0x190 kernel/kcsan/core.c:753 rcu_preempt_read_enter kernel/rcu/tree_plugin.h:391 [inline] __rcu_read_lock+0x36/0x50 kernel/rcu/tree_plugin.h:414 rcu_read_lock include/linux/rcupdate.h:836 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0x33/0xd50 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x91/0xd0 kernel/stacktrace.c:122 ref_tracker_free+0x94/0x3e0 lib/ref_tracker.c:306 netdev_tracker_free include/linux/netdevice.h:4474 [inline] netdev_put include/linux/netdevice.h:4491 [inline] dst_destroy+0x9e/0x330 net/core/dst.c:115 dst_destroy_rcu+0x19/0x20 net/core/dst.c:133 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x47c/0x9b0 kernel/rcu/tree.c:2869 rcu_core_si+0xd/0x20 kernel/rcu/tree.c:2886 handle_softirqs+0xb9/0x280 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:214 spin_unlock_bh include/linux/spinlock.h:396 [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:3288 [inline] process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3371 worker_thread+0x58a/0x780 kernel/workqueue.c:3452 kthread+0x22a/0x280 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-write to 0xffff8881000c5ed8 of 8 bytes by interrupt on cpu 1: wq_worker_tick+0x64/0x240 kernel/workqueue.c:1493 sched_tick+0xbc/0x1f0 kernel/sched/core.c:5672 update_process_times+0x15e/0x190 kernel/time/timer.c:2480 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:1930 [inline] __hrtimer_run_queues+0x276/0x4f0 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x261/0x850 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 __sanitizer_cov_trace_switch+0x7/0x130 kernel/kcov.c:330 kfree_skbmem net/core/skbuff.c:1135 [inline] __kfree_skb+0x69/0x150 net/core/skbuff.c:1204 consume_skb+0x4b/0x130 net/core/skbuff.c:1436 nft_synproxy_eval_v6+0x24f/0x2a0 net/netfilter/nft_synproxy.c:-1 nft_synproxy_do_eval+0x203/0x270 net/netfilter/nft_synproxy.c:146 nft_synproxy_eval+0x29/0x40 net/netfilter/nft_synproxy.c:248 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x1f3/0xd90 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x2f0/0x320 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline] nf_hook_slow+0x78/0x180 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK include/linux/netfilter.h:316 [inline] ip6_input+0x118/0x160 net/ipv6/ip6_input.c:540 dst_input include/net/dst.h:480 [inline] ip6_rcv_finish+0x1f5/0x330 net/ipv6/ip6_input.c:119 NF_HOOK include/linux/netfilter.h:318 [inline] ipv6_rcv+0x72/0x170 net/ipv6/ip6_input.c:351 __netif_receive_skb_one_core net/core/dev.c:6209 [inline] __netif_receive_skb net/core/dev.c:6322 [inline] process_backlog+0x2a5/0x670 net/core/dev.c:6673 __napi_poll+0x61/0x300 net/core/dev.c:7737 napi_poll net/core/dev.c:7800 [inline] net_rx_action+0x452/0x930 net/core/dev.c:7957 handle_softirqs+0xb9/0x280 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:3288 [inline] process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3371 worker_thread+0x58a/0x780 kernel/workqueue.c:3452 kthread+0x22a/0x280 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 value changed: 0x00000000045131b0 -> 0x00000000045158c0 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 857 Comm: kworker/u8:7 Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: events_unbound nsim_dev_trap_report_work 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