syzbot

watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.4.3889:28649]
Modules linked in:
irq event stamp: 11264833
hardirqs last  enabled at (11264832): [<ffffffff8b96fbbc>] irqentry_exit+0x59c/0x620 kernel/entry/common.c:219
hardirqs last disabled at (11264833): [<ffffffff8b96e5ce>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056
softirqs last  enabled at (63378): [<ffffffff8186fcaf>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last  enabled at (63378): [<ffffffff8186fcaf>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last  enabled at (63378): [<ffffffff8186fcaf>] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
softirqs last disabled at (63381): [<ffffffff8186fcaf>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last disabled at (63381): [<ffffffff8186fcaf>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last disabled at (63381): [<ffffffff8186fcaf>] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
CPU: 0 UID: 0 PID: 28649 Comm: syz.4.3889 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 41 a0 f6 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 2b 61 52 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 50 84 f9 09 cc 48 8d 3d 38 12 52
RSP: 0018:ffffc90000007458 EFLAGS: 00000282
RAX: 65c6c34240aa8500 RBX: 0000000000000000 RCX: 0000000000000302
RDX: 000000004830ab97 RSI: ffffffff8df3426e RDI: ffffffff8c073980
RBP: ffffffff81759195 R08: ffffffff81759195 R09: ffffffff8e55a360
R10: ffffc900000070c8 R11: ffffffff81afb170 R12: 0000000000000002
R13: ffffffff8e55a360 R14: 0000000000000000 R15: 0000000000000246
FS:  00007f3195d8b6c0(0000) GS:ffff8881256f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f31931d5d58 CR3: 00000000b0be2000 CR4: 00000000003526f0
DR0: 0000000000000002 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 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+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 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_noprof+0x370/0x6e0 mm/slub.c:5270
 skb_clone+0x212/0x3a0 net/core/skbuff.c:2088
 hsr_forward_do net/hsr/hsr_forward.c:-1 [inline]
 hsr_forward_skb+0x1028/0x2880 net/hsr/hsr_forward.c:743
 send_hsr_supervision_frame+0x731/0xcb0 net/hsr/hsr_device.c:364
 hsr_announce+0x1db/0x370 net/hsr/hsr_device.c:421
 call_timer_fn+0x192/0x5a0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x5f/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:preempt_schedule_irq+0x48/0xa0 kernel/sched/core.c:7194
Code: 49 be 00 00 00 00 00 fc ff df eb 09 48 f7 03 10 00 00 00 74 53 bf 01 00 00 00 e8 b3 9c fa f5 e8 ae 30 34 f6 fb bf 01 00 00 00 <e8> 43 a9 ff ff 9c 58 fa a9 00 02 00 00 74 05 e8 34 32 34 f6 bf 01
RSP: 0018:ffffc90002fd7730 EFLAGS: 00000202
RAX: 0000000000001dc1 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8dcc9112 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffffffff8fef1a77 R09: 1ffffffff1fde34e
R10: dffffc0000000000 R11: fffffbfff1fde34f R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
 irqentry_exit+0x597/0x620 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:81 [inline]
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:103 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
RIP: 0010:unwind_next_frame+0x51a/0x23c0 arch/x86/kernel/unwind_orc.c:510
Code: 83 e0 fe 4c 8d 3c 45 00 00 00 00 49 01 ef 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 27 49 63 07 <4c> 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49 8d 47 fc 48 0f 47 d8
RSP: 0018:ffffc90002fd7858 EFLAGS: 00000246
RAX: fffffffff16e88b0 RBX: ffffffff900731c4 RCX: dffffc0000000000
RDX: ffffffff900731a4 RSI: ffffffff908275d0 RDI: ffffffff8c073920
RBP: ffffffff900731a4 R08: 0000000000000009 R09: ffffffff8e55a360
R10: ffffc90002fd7988 R11: fffff520005faf3d R12: ffffffff8175ba86
R13: ffffffff900731a4 R14: ffffc90002fd7988 R15: ffffffff900731b4
 __unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:773
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xa9/0x100 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_lru_noprof+0x35f/0x6c0 mm/slub.c:5282
 sock_alloc_inode+0x28/0xc0 net/socket.c:322
 alloc_inode+0x6a/0x1b0 fs/inode.c:346
 new_inode_pseudo include/linux/fs.h:2964 [inline]
 sock_alloc net/socket.c:637 [inline]
 __sock_create+0x12d/0x9d0 net/socket.c:1569
 sock_create net/socket.c:1663 [inline]
 __sys_socketpair+0x239/0x560 net/socket.c:1814
 __do_sys_socketpair net/socket.c:1863 [inline]
 __se_sys_socketpair net/socket.c:1860 [inline]
 __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1860
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3194f9aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3195d8b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 00007f3195215fa0 RCX: 00007f3194f9aeb9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000001
RBP: 00007f3195008c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000480 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3195216038 R14: 00007f3195215fa0 R15: 00007ffe14d92d68
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 25767 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xce5/0x1270 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 c4 db 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 6f d7 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 53 d7
RSP: 0018:ffffc900048bf6a0 EFLAGS: 00000293
RAX: ffffffff81b89ffd RBX: 1ffff110170c856d RCX: ffff888030d55b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900048bf7e0 R08: ffffffff8fef1a77 R09: 1ffffffff1fde34e
R10: dffffc0000000000 R11: fffffbfff1fde34f R12: ffff8880b8642b68
R13: dffffc0000000000 R14: ffff8880b873bb00 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881257f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1512b7dff8 CR3: 000000000e346000 CR4: 00000000003526f0
DR0: 0000000000000002 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 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+0x5f5/0x1160 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+0xab/0x290 mm/kfence/core.c:879
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=6bbc/1/0x4000000000000000 softirq=197897/197898 fqs=98
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  2059948          1            0
rcu: 	cputime:    48681       3616           46   ==> 52300(ms)
rcu: 	(t=10500 jiffies g=154981 q=2463 ncpus=2)
rcu: rcu_preempt kthread starved for 814 jiffies! g154981 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27264 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5260 [inline]
 __schedule+0x14ea/0x5050 kernel/sched/core.c:6867
 __schedule_loop kernel/sched/core.c:6949 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:6964
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x1560 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:2285
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 28626 Comm: syz.7.3885 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:37 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:139 [inline]
RIP: 0010:wrmsrq arch/x86/include/asm/msr.h:199 [inline]
RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:212
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 e9 10 c6 25 0a cc 89 f6 31 d2 e9 c6 b0 69 03 66 0f 1f 44 00
RSP: 0018:ffffc90000a08c60 EFLAGS: 00000046
RAX: 0000000000000135 RBX: ffff8880b8723e40 RCX: 0000000000000838
RDX: 0000000000000000 RSI: 0000000000000135 RDI: 0000000000000838
RBP: 0000000000000000 R08: ffffffff81b1b485 R09: ffffffff9a025508
R10: 0000000000000003 R11: ffffffff8172e570 R12: 000000001000035a
R13: dffffc0000000000 R14: 0000000000000135 R15: 0000000000000020
FS:  00007f1042c486c0(0000) GS:ffff8881257f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555e18ce38 CR3: 00000000adc52000 CR4: 00000000003526f0
DR0: 0000000000000002 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 apic_write arch/x86/include/asm/apic.h:409 [inline]
 lapic_next_event+0x11/0x20 arch/x86/kernel/apic/apic.c:418
 clockevents_program_event+0x1c9/0x350 kernel/time/clockevents.c:334
 hrtimer_interrupt+0xb08/0x1010 kernel/time/hrtimer.c:1916
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3d0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:tasklet_action_common+0x85/0x4b0 kernel/softirq.c:915
Code: b8 00 00 00 00 00 fc ff df 48 89 4c 24 28 80 3c 01 00 74 08 4c 89 ff e8 39 b7 a5 00 4d 89 64 24 08 e8 cf 42 45 00 fb 48 85 ed <49> bc 00 00 00 00 00 fc ff df 0f 84 fb 03 00 00 b8 01 00 00 00 44
RSP: 0018:ffffc90000a08ed8 EFLAGS: 00000286
RAX: 0000000000dff978 RBX: 1ffffffff1c4181e RCX: 0000000080000101
RDX: 0000000000000003 RSI: ffffffff8dcc9112 RDI: ffffffff8c073980
RBP: ffff888044fb9650 R08: ffffffff8fef1a77 R09: 1ffffffff1fde34e
R10: dffffc0000000000 R11: fffffbfff1fde34f R12: ffff8880b8724240
R13: 0000000000000006 R14: 0000000000000007 R15: ffff8880b8724248
 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723