watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [syz.2.5056:20941] Modules linked in: CPU: 0 PID: 20941 Comm: syz.2.5056 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:___neigh_lookup_noref include/net/neighbour.h:-1 [inline] RIP: 0010:__ipv6_neigh_lookup_noref include/net/ndisc.h:383 [inline] RIP: 0010:ip6_finish_output2+0x70a/0x1540 net/ipv6/ip6_output.c:127 Code: 08 4c 89 e7 e8 d7 d3 a4 fd 44 89 f3 48 c1 e3 03 49 03 1c 24 48 89 d8 48 c1 e8 03 49 be 00 00 00 00 00 fc ff df 42 80 3c 30 00 <4c> 8b 7c 24 48 74 08 48 89 df e8 a7 d3 a4 fd 4c 8b 2b 4d 85 ed 0f RSP: 0018:ffffc90000007740 EFLAGS: 00000246 RAX: 1ffff110222409a8 RBX: ffff888111204d40 RCX: 00000000000000f6 RDX: ffff88813e5ad828 RSI: 0000000000000000 RDI: ffff88810ef68408 RBP: ffffc900000078a0 R08: ffff88811b335000 R09: 0000000000000002 R10: 000000000000000a R11: 0000000000000101 R12: ffff88810ef68400 R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007ff12e9bf6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1cd4d73e80 CR3: 0000000119b18000 CR4: 00000000003506b0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __ip6_finish_output+0x5fd/0x790 net/ipv6/ip6_output.c:203 ip6_finish_output+0x33/0x1e0 net/ipv6/ip6_output.c:213 NF_HOOK_COND include/linux/netfilter.h:288 [inline] ip6_output+0x1fa/0x420 net/ipv6/ip6_output.c:236 dst_output include/net/dst.h:451 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ndisc_send_skb+0x721/0xbc0 net/ipv6/ndisc.c:513 ndisc_send_rs+0x711/0x960 net/ipv6/ndisc.c:707 addrconf_rs_timer+0x35a/0x600 net/ipv6/addrconf.c:3974 call_timer_fn+0x38/0x290 kernel/time/timer.c:1450 expire_timers kernel/time/timer.c:1495 [inline] __run_timers+0x637/0x9a0 kernel/time/timer.c:1789 run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1802 __do_softirq+0x255/0x563 kernel/softirq.c:309 asm_call_irq_on_stack+0xf/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0x60/0x80 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:405 [inline] __irq_exit_rcu+0x128/0x150 kernel/softirq.c:435 irq_exit_rcu+0x9/0x10 kernel/softirq.c:447 sysvec_apic_timer_interrupt+0xbf/0xe0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635 RIP: 0010:account_kernel_stack+0x279/0x330 kernel/fork.c:402 Code: eb 28 e8 fa 4b 2a 00 48 63 d3 48 c7 c7 c0 95 bf 86 be 24 00 00 00 e8 36 07 56 00 48 8b 44 24 08 48 89 44 24 18 ff 74 24 18 9d <48> c7 44 24 20 0e 36 e0 45 4b c7 44 25 00 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90000c87c40 EFLAGS: 00000246 RAX: 0000000000000246 RBX: 00000000ffffffe0 RCX: b06d4d99ddecda00 RDX: 0000000000000001 RSI: ffffffff8527a9a0 RDI: ffffffff85406a20 RBP: ffffc90000c87d10 R08: ffffffff8640d4e7 R09: 1ffffffff0c81a9c R10: dffffc0000000000 R11: fffffbfff0c81a9d R12: dffffc0000000000 R13: 1ffff92000190f8c R14: 0000000000000000 R15: dead000000000100 release_task_stack kernel/fork.c:438 [inline] put_task_stack+0x9a/0x130 kernel/fork.c:450 finish_task_switch+0x245/0x5a0 kernel/sched/core.c:3918 context_switch kernel/sched/core.c:4051 [inline] __schedule+0xc0b/0x13e0 kernel/sched/core.c:4806 schedule+0x13c/0x1d0 kernel/sched/core.c:4884 exit_to_user_mode_loop+0x4b/0xe0 kernel/entry/common.c:160 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 irqentry_exit_to_user_mode+0x9/0x10 kernel/entry/common.c:287 irqentry_exit+0x12/0x60 kernel/entry/common.c:375 sysvec_apic_timer_interrupt+0xcb/0xe0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635 RIP: 0033:0x7ff12fe2c054 Code: 00 00 00 64 f0 83 04 25 a0 ff ff ff 01 64 48 8b 04 25 00 00 00 00 48 8d b8 d8 fe ff ff e8 74 b1 0d 00 85 c0 0f 84 ec 01 00 00 <64> f0 83 2c 25 a0 ff ff ff 01 e8 1d 93 0c 00 48 8b 4c 24 08 8b 00 RSP: 002b:00007ff12e9bf050 EFLAGS: 00000206 RAX: 00000000000000e3 RBX: 00007ff1301edfa0 RCX: 00007ff12fffd024 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000100 RBP: 00007ff12fffd024 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff1301ee038 R14: 00007ff1301edfa0 R15: 00007fff08db5308 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 20949 Comm: kworker/u4:8 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:check_kcov_mode kernel/kcov.c:165 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x36/0x60 kernel/kcov.c:188 Code: c0 b8 9d 7e 65 8b 15 c5 b8 9d 7e f7 c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74 35 83 b9 dc 0a 00 00 00 74 2c 8b 91 b8 0a 00 00 <83> fa 02 75 21 48 8b 91 c0 0a 00 00 48 8b 32 48 8d 7e 01 8b 89 bc RSP: 0018:ffffc90000cf76f0 EFLAGS: 00000246 RAX: ffffffff815a282c RBX: 0000000000000000 RCX: ffff88813cc5a800 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000cf76f0 R08: ffffffff86c376af R09: 1ffffffff0d86ed5 R10: dffffc0000000000 R11: fffffbfff0d86ed6 R12: dffffc0000000000 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff9200019eee4 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe36b255000 CR3: 000000000640f000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: csd_lock_wait kernel/smp.c:229 [inline] smp_call_function_single+0x21c/0x490 kernel/smp.c:517 smp_call_function_many_cond+0x8f5/0x9d0 kernel/smp.c:653 smp_call_function_many kernel/smp.c:716 [inline] smp_call_function kernel/smp.c:738 [inline] on_each_cpu+0xab/0x180 kernel/smp.c:837 text_poke_sync arch/x86/kernel/alternative.c:1568 [inline] text_poke_bp_batch+0x1cb/0x5f0 arch/x86/kernel/alternative.c:1768 text_poke_flush arch/x86/kernel/alternative.c:1959 [inline] text_poke_finish+0x1a/0x30 arch/x86/kernel/alternative.c:1966 arch_jump_label_transform_apply+0x15/0x30 arch/x86/kernel/jump_label.c:126 __jump_label_update+0x38f/0x3b0 kernel/jump_label.c:459 jump_label_update+0x34c/0x3e0 kernel/jump_label.c:825 static_key_enable_cpuslocked+0x126/0x240 kernel/jump_label.c:177 static_key_enable+0x1a/0x30 kernel/jump_label.c:190 toggle_allocation_gate+0xba/0x440 mm/kfence/core.c:624 process_one_work+0x6fd/0xbc0 kernel/workqueue.c:2301 worker_thread+0xa8e/0x13c0 kernel/workqueue.c:2447 kthread+0x324/0x3b0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298