syzbot

watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.4.1258:10780]
Modules linked in:
irq event stamp: 13986415
hardirqs last  enabled at (13986414): [<ffffffff8b59ae28>] irqentry_exit+0x5e8/0x670 kernel/entry/common.c:219
hardirqs last disabled at (13986415): [<ffffffff8b5997ae>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056
softirqs last  enabled at (13970356): [<ffffffff81853b00>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last  enabled at (13970356): [<ffffffff81853b00>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last  enabled at (13970356): [<ffffffff81853b00>] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723
softirqs last disabled at (13970359): [<ffffffff81853b00>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last disabled at (13970359): [<ffffffff81853b00>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last disabled at (13970359): [<ffffffff81853b00>] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723
CPU: 0 UID: 0 PID: 10780 Comm: syz.4.1258 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x0/0x90 kernel/kcov.c:320
Code: 7c 11 10 48 89 74 11 18 48 89 44 11 20 e9 98 83 9b 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 10 80 92 65 8b 15 78 13
RSP: 0018:ffffc90000006d10 EFLAGS: 00000246
RAX: ffffffff81c53715 RBX: 0000000000000000 RCX: ffff88802be48000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffc90000006f4f R09: 0000000000000000
R10: ffffc90000006f40 R11: fffff52000000dea R12: 0000000000000103
R13: ffffe8ffffccb000 R14: 0000000000000103 R15: dffffc0000000000
FS:  00007f9ca3c756c0(0000) GS:ffff888125e1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9ca3c54d58 CR3: 000000001feaa000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 tracing_gen_ctx_irq_test+0x39/0x160 kernel/trace/trace.c:2604
 tracing_gen_ctx_flags include/linux/trace_events.h:201 [inline]
 tracing_gen_ctx include/linux/trace_events.h:208 [inline]
 perf_trace_buf_update+0x3f/0x190 kernel/trace/trace_event_perf.c:429
 perf_tp_event+0xf6/0x1380 kernel/events/core.c:11067
 perf_trace_run_bpf_submit+0xee/0x170 kernel/events/core.c:11005
 do_perf_trace_lock_acquire include/trace/events/lock.h:24 [inline]
 perf_trace_lock_acquire+0x335/0x410 include/trace/events/lock.h:24
 __do_trace_lock_acquire include/trace/events/lock.h:24 [inline]
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x2ef/0x340 kernel/locking/lockdep.c:5831
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 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]
 _sctp_make_chunk+0x59/0x290 net/sctp/sm_make_chunk.c:1435
 sctp_make_control net/sctp/sm_make_chunk.c:1482 [inline]
 sctp_make_heartbeat+0xa7/0x470 net/sctp/sm_make_chunk.c:1161
 sctp_sf_heartbeat net/sctp/sm_statefuns.c:1026 [inline]
 sctp_sf_sendbeat_8_3+0x22e/0x650 net/sctp/sm_statefuns.c:1070
 sctp_do_sm+0x1e7/0x5c40 net/sctp/sm_sideeffect.c:1172
 sctp_generate_heartbeat_event+0x2f8/0x450 net/sctp/sm_sideeffect.c:396
 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:235
Code: 48 16 00 00 83 fa 02 75 21 48 8b 91 50 16 00 00 48 8b 32 48 8d 7e 01 8b 89 4c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 <e9> fe 87 9b 09 cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc9000b4beef8 EFLAGS: 00000287
RAX: ffffffff81845450 RBX: ffff88802be48000 RCX: 0000000000080000
RDX: ffffc9000dcac000 RSI: 000000000000c162 RDI: 000000000000c163
RBP: ffffc9000b4bf118 R08: ffffffff8f822377 R09: 1ffffffff1f0446e
R10: dffffc0000000000 R11: fffffbfff1f0446f R12: dffffc0000000000
R13: ffff88802ed9bd00 R14: ffff888059dc1e80 R15: 1ffff110170c7686
 put_task_struct_rcu_user+0x10/0xa0 kernel/exit.c:235
 context_switch kernel/sched/core.c:5259 [inline]
 __schedule+0x14a3/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7140
 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
 class_preempt_notrace_destructor include/linux/preempt.h:469 [inline]
 __do_trace_lock_acquire include/trace/events/lock.h:24 [inline]
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x325/0x340 kernel/locking/lockdep.c:5831
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf5/0x1f0 mm/page_owner.c:165
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
 ___free_pages_bulk mm/kasan/shadow.c:333 [inline]
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:385 [inline]
 __kasan_populate_vmalloc+0x137/0x1d0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xdc4/0x14e0 mm/vmalloc.c:2124
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3219
 __vmalloc_node_range_noprof+0x371/0x16a0 mm/vmalloc.c:4011
 __vmalloc_node_noprof mm/vmalloc.c:4111 [inline]
 __vmalloc_noprof+0xd2/0x120 mm/vmalloc.c:4127
 bpf_prog_alloc_no_stats+0x4a/0x4d0 kernel/bpf/core.c:106
 bpf_prog_alloc+0x3c/0x1a0 kernel/bpf/core.c:153
 bpf_prog_load+0x735/0x1a10 kernel/bpf/syscall.c:2992
 __sys_bpf+0x507/0x860 kernel/bpf/syscall.c:6164
 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6272 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6272
 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: 0033:0x7f9ca2d8f749
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:00007f9ca3c75038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f9ca2fe5fa0 RCX: 00007f9ca2d8f749
RDX: 0000000000000094 RSI: 00002000000018c0 RDI: 0000000000000005
RBP: 00007f9ca2e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9ca2fe6038 R14: 00007f9ca2fe5fa0 R15: 00007ffd08887308
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 9730 Comm: kworker/u8:26 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:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400
Code: e8 5e cf a6 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 df ef 0c fd 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 8a 57 42 06 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000a084f8 EFLAGS: 00000006
RAX: 1ffffffff3381405 RBX: 00000000000003f9 RCX: 0000000000000000
RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffc90000a08690 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff851a2810 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff99c0a2c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdbee0e0700 CR3: 000000000dd3a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000200000000300
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 serial_port_in include/linux/serial_core.h:806 [inline]
 serial8250_console_write+0x542/0x1b60 drivers/tty/serial/8250/8250_port.c:3306
 console_emit_next_record kernel/printk/printk.c:3129 [inline]
 console_flush_one_record kernel/printk/printk.c:3215 [inline]
 console_flush_all+0x713/0xb00 kernel/printk/printk.c:3289
 __console_flush_and_unlock kernel/printk/printk.c:3319 [inline]
 console_unlock+0xbb/0x190 kernel/printk/printk.c:3359
 vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2426
 _printk+0xcf/0x120 kernel/printk/printk.c:2451
 print_other_cpu_stall+0x189/0x1340 kernel/rcu/tree_stall.h:656
 check_cpu_stall kernel/rcu/tree_stall.h:856 [inline]
 rcu_pending kernel/rcu/tree.c:3667 [inline]
 rcu_sched_clock_irq+0x9a9/0x1140 kernel/rcu/tree.c:2704
 update_process_times+0x23c/0x2f0 kernel/time/timer.c:2474
 tick_sched_handle kernel/time/tick-sched.c:298 [inline]
 tick_nohz_handler+0x3e9/0x710 kernel/time/tick-sched.c:319
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x4d0/0xc30 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:417
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <c3> cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 ab 9e d6 f5 cc
RSP: 0018:ffffc9000c177698 EFLAGS: 00000293
RAX: ffffffff81b5644d RBX: 1ffff110170c856d RCX: ffff88806a815b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000c1777e0 R08: ffffffff8f822377 R09: 1ffffffff1f0446e
R10: dffffc0000000000 R11: fffffbfff1f0446f R12: ffff8880b8642b68
R13: dffffc0000000000 R14: ffff8880b873bb00 R15: 0000000000000000
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0xcdd/0x1260 kernel/smp.c:877
 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
 </TASK>