================================================================== 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 find_watchpoint kernel/kcsan/core.c:120 [inline] check_access kernel/kcsan/core.c:737 [inline] __tsan_read8+0x20/0x190 kernel/kcsan/core.c:1025 ip6_mc_input+0x33/0x470 net/ipv6/ip6_input.c:511 dst_input include/net/dst.h:480 [inline] ip6_rcv_finish+0x31f/0x330 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:318 [inline] ipv6_rcv+0x72/0x170 net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6164 [inline] __netif_receive_skb net/core/dev.c:6277 [inline] netif_receive_skb_internal net/core/dev.c:6363 [inline] netif_receive_skb+0xc5/0x530 net/core/dev.c:6422 br_netif_receive_skb net/bridge/br_input.c:30 [inline] NF_HOOK include/linux/netfilter.h:318 [inline] br_pass_frame_up+0x23b/0x330 net/bridge/br_input.c:70 br_handle_frame_finish+0xdd7/0xfd0 net/bridge/br_input.c:-1 nf_hook_bridge_pre net/bridge/br_input.c:313 [inline] br_handle_frame+0x452/0xa60 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 local_bh_enable include/linux/bottom_half.h:33 [inline] __alloc_skb+0x2b6/0x690 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 kcsan_setup_watchpoint+0x404/0x410 kernel/kcsan/core.c:705 ndisc_recv_na+0x245/0x8f0 net/ipv6/ndisc.c:1030 ndisc_rcv+0x307/0x400 net/ipv6/ndisc.c:1833 icmpv6_rcv+0xe66/0x1300 net/ipv6/icmp.c:1193 ip6_protocol_deliver_rcu+0xb37/0x10f0 net/ipv6/ip6_input.c:438 ip6_input_finish+0xf0/0x1c0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x5e/0x160 net/ipv6/ip6_input.c:500 ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:480 [inline] ip6_rcv_finish+0x31f/0x330 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:318 [inline] ipv6_rcv+0x72/0x170 net/ipv6/ip6_input.c:311 __netif_receive_skb_one_core net/core/dev.c:6164 [inline] __netif_receive_skb net/core/dev.c:6277 [inline] netif_receive_skb_internal net/core/dev.c:6363 [inline] netif_receive_skb+0xc5/0x530 net/core/dev.c:6422 br_netif_receive_skb net/bridge/br_input.c:30 [inline] NF_HOOK include/linux/netfilter.h:318 [inline] br_pass_frame_up+0x23b/0x330 net/bridge/br_input.c:70 br_handle_frame_finish+0xdd7/0xfd0 net/bridge/br_input.c:-1 nf_hook_bridge_pre net/bridge/br_input.c:313 [inline] br_handle_frame+0x452/0xa60 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 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 value changed: 0x000000000106e8b0 -> 0x0000000001070fc0 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 16747 Comm: kworker/u8:25 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 ================================================================== net_ratelimit: 156025 callbacks suppressed ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on vlan4! bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on vlan4! bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on vlan4! bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on vlan4! bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on vlan4! net_ratelimit: 165524 callbacks suppressed ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on vlan4! bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on vlan4! bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0) ICMPv6: NA: aa:aa:aa:aa:aa:0c advertised our address fe80::a8aa:aaff:feaa:aa0c on vlan4!