BUG: soft lockup in __run_timer_base

Status: auto-obsoleted due to no activity on 2026/05/24 04:21
Subsystems: kernel
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+84c312029a2056dc716b@syzkaller.appspotmail.com
First crash: 157d, last: 157d
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
740ba31b assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ BUG: soft lockup in __run_timer_base 2026/05/22 06:54 2026/05/22 06:54 2026/05/22 07:54 70ae9b03 

			
				
	

	
	



			

		

	

	
	

		

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			Similar bugs (3)
		

		

			




	
	

		
			Kernel
		
		Title
		
			Rank
			
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		Repro
		Cause bisect
		Fix bisect
		Count
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		Reported
		
		
		
			Patched
		
		
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			upstream
			
				INFO: rcu detected stall in __run_timer_base (3)
					kasan
					mm
			
			1
			
			
			
			6
			387d
			
				
					563d
				
			
			
			
			
				0/29
			
			
				
					
						auto-obsoleted due to no activity on 2025/10/06 12:53
					
				
			
			
		

	
		

			upstream
			
				INFO: rcu detected stall in __run_timer_base
					usb
			
			1
			syz, C
			done
			done
			10
			769d
			
				
					837d
				
			
			
			
			
				26/29
			
			
				
					
						fixed on 2024/07/31 23:31
					
				
			
			
		

	
		

			upstream
			
				INFO: rcu detected stall in __run_timer_base (2)
					exfat
			
			1
			
			
			
			1
			685d
			
				
					685d
				
			
			
			
			
				0/29
			
			
				
					
						auto-obsoleted due to no activity on 2024/12/12 02:02
					
				
			
			
		

	
	





			
			
			
			
		

	

	

	
	
Sample crash report:

	
watchdog: BUG: soft lockup - CPU#0 stuck for 144s! [syz.5.811:11802]
Modules linked in:
irq event stamp: 17868047
hardirqs last  enabled at (17868046): [<ffffffff8bad1f2e>] irqentry_exit+0x59e/0x620 kernel/entry/common.c:242
hardirqs last disabled at (17868047): [<ffffffff8bad093e>] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056
softirqs last  enabled at (17867664): [<ffffffff8187fdef>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last  enabled at (17867664): [<ffffffff8187fdef>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last  enabled at (17867664): [<ffffffff8187fdef>] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
softirqs last disabled at (17867667): [<ffffffff8187fdef>] __do_softirq kernel/softirq.c:656 [inline]
softirqs last disabled at (17867667): [<ffffffff8187fdef>] invoke_softirq kernel/softirq.c:496 [inline]
softirqs last disabled at (17867667): [<ffffffff8187fdef>] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
CPU: 0 UID: 0 PID: 11802 Comm: syz.5.811 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ba fa f1 f5 48 89 df e8 f2 6f f2 f5 e8 7d c0 1d f6 fb bf 01 00 00 00 <e8> 52 36 e4 f5 65 8b 05 1b ef 6b 07 85 c0 74 07 5b e9 01 48 00 00
RSP: 0018:ffffc90000007d90 EFLAGS: 00000216
RAX: 000000000110a500 RBX: ffff8880b8626100 RCX: 0000000000000102
RDX: 0000000000000003 RSI: ffffffff8def196a RDI: 0000000000000001
RBP: ffffc90000007f08 R08: ffffffff901172b7 R09: 1ffffffff2022e56
R10: dffffc0000000000 R11: fffffbfff2022e57 R12: ffff8880b8626100
R13: 1ffff92000000fcc R14: ffff888057c4fc10 R15: ffffc90000007e60
FS:  00007fd1bb4fc6c0(0000) GS:ffff888125466000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb1cae02cdb CR3: 000000005a2f8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 expire_timers kernel/time/timer.c:1798 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x642/0x8b0 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/0x870 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:__schedule+0x0/0x5340 kernel/sched/core.c:6762
Code: 81 f6 45 89 f8 89 d9 48 8b 5c 24 08 e9 ee fe ff ff cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48
RSP: 0018:ffffc900043d7128 EFLAGS: 00000206
RAX: 00000000009c8b77 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000007 RSI: ffffffff8def196a RDI: 0000000000000001
RBP: 0000000000000000 R08: ffffffff901172b7 R09: 1ffffffff2022e56
R10: dffffc0000000000 R11: fffffbfff2022e57 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234
 irqentry_exit+0x599/0x620 kernel/entry/common.c:239
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x6f/0x80 kernel/locking/spinlock.c:194
Code: 00 00 e8 c4 36 e4 f5 65 8b 05 8d ef 6b 07 85 c0 74 18 5b 41 5e c3 cc cc cc cc cc e8 db 61 fd ff f7 c3 00 02 00 00 75 d4 eb d3 <e8> 2c fd 83 f5 eb e1 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffc900043d7250 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000286 RCX: 0000000000000000
RDX: 0000000000000007 RSI: ffffffff8def196a RDI: 00000000ffffffff
RBP: dffffc0000000000 R08: ffffffff901172b7 R09: 1ffffffff2022e56
R10: dffffc0000000000 R11: fffffbfff2022e57 R12: 1ffff1100d886be8
R13: ffffc900043d0000 R14: ffffffff8e766640 R15: dffffc0000000000
 __rcu_read_unlock+0x83/0xe0 kernel/rcu/tree_plugin.h:438
 rcu_read_unlock include/linux/rcupdate.h:883 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0x1aaf/0x23c0 arch/x86/kernel/unwind_orc.c:695
 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 save_stack+0x122/0x230 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:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __slab_free+0x263/0x2b0 mm/slub.c:5532
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 __do_kmalloc_node mm/slub.c:5218 [inline]
 __kmalloc_noprof+0x316/0x760 mm/slub.c:5231
 kmalloc_noprof include/linux/slab.h:966 [inline]
 kmalloc_array_noprof include/linux/slab.h:1113 [inline]
 security_inode_init_security+0x102/0x3d0 security/security.c:1321
 shmem_mknod+0x1fe/0x360 mm/shmem.c:3892
 lookup_open fs/namei.c:4483 [inline]
 open_last_lookups fs/namei.c:4583 [inline]
 path_openat+0x1395/0x3860 fs/namei.c:4827
 do_file_open+0x23e/0x4a0 fs/namei.c:4859
 do_sys_openat2+0x113/0x200 fs/open.c:1366
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd1ba59c629
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:00007fd1bb4fc028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fd1ba815fa0 RCX: 00007fd1ba59c629
RDX: 00000000000026e1 RSI: 0000200000000080 RDI: ffffffffffffff9c
RBP: 00007fd1ba632b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd1ba816038 R14: 00007fd1ba815fa0 R15: 00007ffdab0e6408
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1155 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xce5/0x12c0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 24 e3 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 cf de 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 b3 de
RSP: 0018:ffffc90004d5f720 EFLAGS: 00000293
RAX: ffffffff81b9addd RBX: 1ffff110170c8515 RCX: ffff888028a95ac0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004d5f860 R08: ffffffff901172b7 R09: 1ffffffff2022e56
R10: dffffc0000000000 R11: fffffbfff2022e57 R12: ffff8880b86428a8
R13: dffffc0000000000 R14: ffff8880b873bf80 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125566000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007eff48416038 CR3: 000000000e54c000 CR4: 00000000003526f0
DR0: 0000000000000000 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:72 [inline]
 smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2746 [inline]
 smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2956
 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:899
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>



	

	



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			2026/02/23 04:20
			bpf-next
			9cd168a2720b
			6e7b5511
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			ci-upstream-bpf-next-kasan-gce
			BUG: soft lockup in __run_timer_base
		

		
		


* Struck through repros no longer work on HEAD.