syzbot

watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.4.60:6120]
Modules linked in:
irq event stamp: 18347897
hardirqs last  enabled at (18347896): [<ffffffff8b5623c4>] irqentry_exit+0x74/0x90 kernel/entry/common.c:357
hardirqs last disabled at (18347897): [<ffffffff8b560dbe>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1049
softirqs last  enabled at (588878): [<ffffffff8185c3fa>] __do_softirq kernel/softirq.c:613 [inline]
softirqs last  enabled at (588878): [<ffffffff8185c3fa>] invoke_softirq kernel/softirq.c:453 [inline]
softirqs last  enabled at (588878): [<ffffffff8185c3fa>] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
softirqs last disabled at (588881): [<ffffffff8185c3fa>] __do_softirq kernel/softirq.c:613 [inline]
softirqs last disabled at (588881): [<ffffffff8185c3fa>] invoke_softirq kernel/softirq.c:453 [inline]
softirqs last disabled at (588881): [<ffffffff8185c3fa>] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
CPU: 0 UID: 0 PID: 6120 Comm: syz.4.60 Not tainted 6.15.0-rc4-syzkaller-g25b6d5def6f8 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:rcu_read_unlock_special+0x87/0x4c0 kernel/rcu/tree_plugin.h:694
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 e2 c3 cd 10 41 f7 c6 00 00 f0 00 74 49 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc90000007540 EFLAGS: 00000206
RAX: 3d98612fa9022200 RBX: 1ffff92000000eb0 RCX: 3d98612fa9022200
RDX: 0000000000000002 RSI: ffffffff8d74ad15 RDI: ffffffff8bc1d460
RBP: ffffc90000007638 R08: ffffffff8f7ed377 R09: 1ffffffff1efda6e
R10: dffffc0000000000 R11: fffffbfff1efda6f R12: ffffffff8df40c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
FS:  00007f751e6576c0(0000) GS:ffff8881260ca000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ff13ff8 CR3: 000000001f6ea000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __rcu_read_unlock+0x84/0xe0 kernel/rcu/tree_plugin.h:438
 rcu_read_unlock include/linux/rcupdate.h:873 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x19ae/0x2390 arch/x86/kernel/unwind_orc.c:680
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:548
 slab_free_hook mm/slub.c:2359 [inline]
 slab_free mm/slub.c:4656 [inline]
 kmem_cache_free+0x2ee/0x3f0 mm/slub.c:4758
 inet_twsk_free net/ipv4/inet_timewait_sock.c:78 [inline]
 inet_twsk_put net/ipv4/inet_timewait_sock.c:85 [inline]
 inet_twsk_kill+0x6d6/0x840 net/ipv4/inet_timewait_sock.c:71
 call_timer_fn+0x17b/0x5f0 kernel/time/timer.c:1789
 expire_timers kernel/time/timer.c:1840 [inline]
 __run_timers kernel/time/timer.c:2414 [inline]
 __run_timer_base+0x61a/0x860 kernel/time/timer.c:2426
 run_timer_base kernel/time/timer.c:2435 [inline]
 run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2445
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0xa3/0xc0 arch/x86/kernel/irq_work.c:17
 </IRQ>
 <TASK>
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:738
RIP: 0010:preempt_schedule_irq+0xb0/0x150 kernel/sched/core.c:7090
Code: 24 20 f6 44 24 21 02 74 0c 90 0f 0b 48 f7 03 08 00 00 00 74 64 bf 01 00 00 00 e8 eb 83 39 f6 e8 86 03 70 f6 fb bf 01 00 00 00 <e8> 4b ab ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc90004f57460 EFLAGS: 00000286
RAX: 3d98612fa9022200 RBX: 0000000000000000 RCX: 3d98612fa9022200
RDX: 0000000000000006 RSI: ffffffff8d74ad15 RDI: 0000000000000001
RBP: ffffc90004f57500 R08: ffffffff8f7ed377 R09: 1ffffffff1efda6e
R10: dffffc0000000000 R11: fffffbfff1efda6f R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff920009eae8c
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:104 [inline]
RIP: 0010:__local_bh_enable_ip+0x135/0x1c0 kernel/softirq.c:414
Code: 8b e8 ef 7b d0 09 65 66 8b 05 2f a9 ef 10 66 85 c0 75 5a bf 01 00 00 00 e8 28 07 0b 00 e8 13 85 41 00 fb 65 8b 05 0b a9 ef 10 <85> c0 75 05 e8 72 cd ad ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc90004f575c0 EFLAGS: 00000282
RAX: 0000000000000000 RBX: 0000000000000201 RCX: 3d98612fa9022200
RDX: 0000000000000006 RSI: ffffffff8d74ad15 RDI: ffffffff8bc1d460
RBP: ffffc90004f57650 R08: ffffffff8f7ed377 R09: 1ffffffff1efda6e
R10: dffffc0000000000 R11: fffffbfff1efda6f R12: ffffffff8a0e973a
R13: ffff8880b883b980 R14: dffffc0000000000 R15: 1ffff920009eaeb8
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 rt6_uncached_list_flush_dev net/ipv6/route.c:193 [inline]
 rt6_disable_ip+0x67a/0x720 net/ipv6/route.c:4957
 addrconf_ifdown+0x15d/0x1880 net/ipv6/addrconf.c:3854
 addrconf_notify+0x1bc/0x1010 net/ipv6/addrconf.c:-1
 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
 call_netdevice_notifiers_mtu net/core/dev.c:2251 [inline]
 netif_set_mtu_ext+0x438/0x620 net/core/dev.c:9499
 netif_set_mtu+0xb8/0x180 net/core/dev.c:9520
 dev_set_mtu+0x126/0x260 net/core/dev_api.c:247
 dev_ioctl+0x7b4/0x1150 net/core/dev_ioctl.c:821
 sock_do_ioctl+0x22c/0x300 net/socket.c:1204
 sock_ioctl+0x576/0x790 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f751d78e969
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:00007f751e657038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f751d9b5fa0 RCX: 00007f751d78e969
RDX: 0000200000000080 RSI: 0000000000008922 RDI: 000000000000000b
RBP: 00007f751d810ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f751d9b5fa0 R15: 00007fff64937c08
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6148 Comm: kworker/u8:14 Not tainted 6.15.0-rc4-syzkaller-g25b6d5def6f8 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:check_kcov_mode kernel/kcov.c:194 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x70 kernel/kcov.c:217
Code: 08 60 75 92 65 8b 15 48 a1 b5 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 3c 16 00 00 00 74 2c 8b 91 18 16 00 00 <83> fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 48 8d 7e 01 8b 89 1c
RSP: 0018:ffffc9000b41f6f8 EFLAGS: 00000246
RAX: ffffffff81b45620 RBX: ffff8880b893ad40 RCX: ffff88801ff09e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000b41f860 R08: ffffffff8f7ed377 R09: 1ffffffff1efda6e
R10: dffffc0000000000 R11: fffffbfff1efda6f R12: 1ffff11017108245
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8841228
FS:  0000000000000000(0000) GS:ffff8881261ca000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7a1ca1c1f7 CR3: 000000000dd36000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:340 [inline]
 smp_call_function_many_cond+0xe80/0x11c0 kernel/smp.c:885
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2455 [inline]
 text_poke_bp_batch+0x319/0x940 arch/x86/kernel/alternative.c:2665
 text_poke_flush arch/x86/kernel/alternative.c:2856 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2863
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>