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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: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
 __tsan_read8+0x0/0x190 kernel/kcsan/core.c:753
 nft_synproxy_tcp_options net/netfilter/nft_synproxy.c:29 [inline]
 nft_synproxy_eval_v4+0x115/0x270 net/netfilter/nft_synproxy.c:58
 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:6212 [inline]
 __netif_receive_skb net/core/dev.c:6325 [inline]
 process_backlog+0x333/0x680 net/core/dev.c:6676
 __napi_poll+0x61/0x300 net/core/dev.c:7735
 napi_poll net/core/dev.c:7798 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7955
 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+0x521/0x630 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 0xffff8881000c5ed8 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
 __tsan_read4+0x0/0x190 kernel/kcsan/core.c:753
 ip_route_output_key_hash_rcu+0x808/0x1320 net/ipv4/route.c:2858
 ip_route_output_key_hash net/ipv4/route.c:2700 [inline]
 __ip_route_output_key include/net/route.h:169 [inline]
 ip_route_output_flow+0x65/0x110 net/ipv4/route.c:2927
 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:6212 [inline]
 __netif_receive_skb net/core/dev.c:6325 [inline]
 process_backlog+0x333/0x680 net/core/dev.c:6676
 __napi_poll+0x61/0x300 net/core/dev.c:7735
 napi_poll net/core/dev.c:7798 [inline]
 net_rx_action+0x456/0x930 net/core/dev.c:7955
 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: 0x0000000000641900 -> 0x0000000000644010

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 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
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