watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.2.4922:24459] Modules linked in: irq event stamp: 5047353 hardirqs last enabled at (5047352): [] irqentry_exit+0x5e8/0x670 kernel/entry/common.c:219 hardirqs last disabled at (5047353): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056 softirqs last enabled at (0): [] rcu_lock_acquire include/linux/rcupdate.h:331 [inline] softirqs last enabled at (0): [] rcu_read_lock include/linux/rcupdate.h:867 [inline] softirqs last enabled at (0): [] copy_process+0x915/0x3950 kernel/fork.c:2091 softirqs last disabled at (801): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last disabled at (801): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (801): [] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 CPU: 0 UID: 0 PID: 24459 Comm: syz.2.4922 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:rcu_read_unlock_special+0x1d/0x420 kernel/rcu/tree_plugin.h:770 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 10 65 8b 2d 7b 6f d8 10 f7 c5 00 00 f0 00 74 14 <48> 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d e9 50 4f b5 09 cc 49 89 RSP: 0018:ffffc900000074e0 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000246 RCX: 0000000000000101 RDX: 0000000000000002 RSI: ffffffff8d793871 RDI: ffffffff8bc08a60 RBP: ffff888125e1e000 R08: ffffffff8f822a77 R09: 1ffffffff1f0454e R10: dffffc0000000000 R11: fffffbfff1f0454f R12: ffffffff8df46ef8 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b863b8e8 FS: 00007fb03d19c6c0(0000) GS:ffff888125e1e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32e23ffc CR3: 0000000033a1e000 CR4: 00000000003526f0 DR0: 0000000000000008 DR1: 0000000000000008 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __rcu_read_unlock+0x84/0xe0 kernel/rcu/tree_plugin.h:438 rcu_read_unlock include/linux/rcupdate.h:899 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x1ab6/0x23d0 arch/x86/kernel/unwind_orc.c:695 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_node_noprof+0x43c/0x720 mm/slub.c:5315 kmalloc_reserve+0xbd/0x290 net/core/skbuff.c:586 __alloc_skb+0x204/0x3a0 net/core/skbuff.c:690 alloc_skb include/linux/skbuff.h:1383 [inline] ndisc_alloc_skb+0x9f/0x480 net/ipv6/ndisc.c:420 ndisc_send_rs+0x2b5/0x630 net/ipv6/ndisc.c:706 addrconf_rs_timer+0x369/0x6a0 net/ipv6/addrconf.c:4037 call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x61a/0x860 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:generic_exec_single+0x3ef/0x430 kernel/smp.c:453 Code: 75 11 e8 44 a3 0b 00 48 85 db 75 16 e8 3a a3 0b 00 eb 15 e8 33 a3 0b 00 e8 be cb a4 09 48 85 db 74 ea e8 24 a3 0b 00 fb 31 c0 <48> 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 08 RSP: 0018:ffffc9000be87aa0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000080000 RDX: ffffc90014333000 RSI: 00000000000021e8 RDI: 00000000000021e9 RBP: 0000000000000001 R08: ffffffff8f822a77 R09: 1ffffffff1f0454e R10: dffffc0000000000 R11: fffffbfff1f0454f R12: 1ffff920017d0f65 R13: 1ffff920017d0f67 R14: 0000000000000000 R15: ffffc9000be87b38 smp_call_function_single+0x332/0x570 kernel/smp.c:684 task_function_call kernel/events/core.c:122 [inline] perf_install_in_context+0x593/0x8f0 kernel/events/core.c:3105 __do_sys_perf_event_open kernel/events/core.c:13820 [inline] __se_sys_perf_event_open+0x1966/0x1d90 kernel/events/core.c:13462 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb03c38f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb03d19c038 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007fb03c5e5fa0 RCX: 00007fb03c38f749 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000180 RBP: 00007fb03c413f91 R08: 0000000000000002 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb03c5e6038 R14: 00007fb03c5e5fa0 R15: 00007ffd84588288 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 17477 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xcca/0x1260 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 d4 97 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f 93 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 63 93 0b 00 eb e4 44 RSP: 0018:ffffc9000d2876a0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110170c856d RCX: ffff88801f311e80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000d2877e0 R08: ffffffff8f822a77 R09: 1ffffffff1f0454e R10: dffffc0000000000 R11: fffffbfff1f0454f R12: ffff8880b8642b68 R13: dffffc0000000000 R14: ffff8880b873bb00 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125f1e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcc301dfb0 CR3: 000000000dd3a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2711 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2921 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:874 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246