================================================================== BUG: KCSAN: data-race in wq_worker_tick / wq_worker_tick read-write to 0xffff8881000c5cd8 of 8 bytes by interrupt on cpu 0: wq_worker_tick+0x64/0x240 kernel/workqueue.c:1508 sched_tick+0xbc/0x1f0 kernel/sched/core.c:5804 update_process_times+0x15e/0x190 kernel/time/timer.c:2480 tick_sched_handle kernel/time/tick-sched.c:296 [inline] tick_nohz_handler+0x227/0x380 kernel/time/tick-sched.c:317 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x257/0x810 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 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_read2+0x2c/0x190 kernel/kcsan/core.c:1023 nf_hook_slow+0xdc/0x180 net/netfilter/core.c:618 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK include/linux/netfilter.h:316 [inline] ip_rcv+0x11f/0x160 net/ipv4/ip_input.c:612 __netif_receive_skb_one_core net/core/dev.c:6216 [inline] __netif_receive_skb net/core/dev.c:6329 [inline] process_backlog+0x333/0x680 net/core/dev.c:6680 __napi_poll+0x61/0x300 net/core/dev.c:7739 napi_poll net/core/dev.c:7802 [inline] net_rx_action+0x456/0x930 net/core/dev.c:7959 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+0x6b1/0x6f0 net/core/skbuff.c:699 alloc_skb include/linux/skbuff.h:1384 [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+0x18b/0x630 drivers/net/netdevsim/dev.c:922 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-write to 0xffff8881000c5cd8 of 8 bytes by interrupt on cpu 1: wq_worker_tick+0x64/0x240 kernel/workqueue.c:1508 sched_tick+0xbc/0x1f0 kernel/sched/core.c:5804 update_process_times+0x15e/0x190 kernel/time/timer.c:2480 tick_sched_handle kernel/time/tick-sched.c:296 [inline] tick_nohz_handler+0x227/0x380 kernel/time/tick-sched.c:317 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x257/0x810 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x32/0x80 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 orc_find arch/x86/kernel/unwind_orc.c:229 [inline] unwind_next_frame+0xb0/0xd40 arch/x86/kernel/unwind_orc.c:510 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x91/0xd0 kernel/stacktrace.c:122 ref_tracker_alloc+0x101/0x2f0 lib/ref_tracker.c:276 __netdev_tracker_alloc include/linux/netdevice.h:4496 [inline] netdev_hold include/linux/netdevice.h:4525 [inline] dst_init+0x8c/0x250 net/core/dst.c:52 dst_alloc+0xe0/0x100 net/core/dst.c:94 rt_dst_alloc net/ipv4/route.c:1676 [inline] __mkroute_output net/ipv4/route.c:2679 [inline] ip_route_output_key_hash_rcu+0xed9/0x1320 net/ipv4/route.c:2899 ip_route_output_key_hash net/ipv4/route.c:2729 [inline] __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x65/0x110 net/ipv4/route.c:2956 ip_route_output_key include/net/route.h:179 [inline] ip_route_me_harder+0x40c/0x690 net/ipv4/netfilter.c:54 synproxy_send_tcp+0x1e2/0x2e0 net/netfilter/nf_synproxy_core.c:434 synproxy_send_client_synack+0x55e/0x5b0 net/netfilter/nf_synproxy_core.c:487 nft_synproxy_eval_v4+0x21f/0x270 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x1cf/0x270 net/netfilter/nft_synproxy.c:141 nft_synproxy_eval+0x29/0x40 net/netfilter/nft_synproxy.c:247 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x1ff/0xde0 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] ip_local_deliver+0x199/0x1e0 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:481 [inline] ip_rcv_finish+0x188/0x1a0 net/ipv4/ip_input.c:492 NF_HOOK include/linux/netfilter.h:318 [inline] ip_rcv+0x62/0x160 net/ipv4/ip_input.c:612 __netif_receive_skb_one_core net/core/dev.c:6216 [inline] __netif_receive_skb net/core/dev.c:6329 [inline] process_backlog+0x333/0x680 net/core/dev.c:6680 __napi_poll+0x61/0x300 net/core/dev.c:7739 napi_poll net/core/dev.c:7802 [inline] net_rx_action+0x456/0x930 net/core/dev.c:7959 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+0x6b1/0x6f0 net/core/skbuff.c:699 alloc_skb include/linux/skbuff.h:1384 [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+0x18b/0x630 drivers/net/netdevsim/dev.c:922 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 value changed: 0x0000000003420ba0 -> 0x00000000034232b0 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 4345 Comm: kworker/u8:15 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: events_unbound nsim_dev_trap_report_work ==================================================================