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WARNING: kernel/rcu/tree_stall.h:1049 at rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1049, CPU#0: kworker/u8:19/6279
Modules linked in:
CPU: 0 UID: 0 PID: 6279 Comm: kworker/u8:19 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1049
Code: 88 61 01 00 00 be 04 00 00 00 48 c7 c7 40 43 1a 9b e8 d0 22 88 00 b8 01 00 00 00 87 05 e5 19 2d 19 85 c0 0f 85 3d 01 00 00 90 <0f> 0b 90 48 c7 c3 c4 fe d7 90 48 81 fd c0 08 7f 8e 74 5a 48 b8 00
RSP: 0018:ffffc90000007de8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000002904 RCX: ffffffff81ed2950
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff9b1a4340
RBP: ffffffff8e7f08c0 R08: 0000000000000001 R09: fffffbfff3634868
R10: 0000000000000003 R11: 0000000000000000 R12: 1ffffffff1c81e50
R13: 0000000000000246 R14: 0000000000000020 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124376000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fca2b08b000 CR3: 000000000e596000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:1012 [inline]
 rcu_core+0x2cb/0x10d0 kernel/rcu/tree.c:2864
 handle_softirqs+0x1ea/0xa00 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892
Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 69 83 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31
RSP: 0018:ffffc900088b7870 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fbfebd
RDX: ffff88802cb83d80 RSI: ffffffff81fbfe97 RDI: ffff88802cb83d80
RBP: ffff8880b8541080 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170a8211 R14: 0000000000000001 R15: ffff8880b843c700
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
 on_each_cpu include/linux/smp.h:72 [inline]
 smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline]
 smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x37a/0x550 kernel/jump_label.c:910
 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210
 static_key_enable+0x1a/0x20 kernel/jump_label.c:223
 toggle_allocation_gate mm/kfence/core.c:906 [inline]
 toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:898
 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302
 process_scheduled_works kernel/workqueue.c:3385 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	b8 00 00 00 00       	mov    $0x0,%eax
   5:	00 fc                	add    %bh,%ah
   7:	ff                   	lcall  (bad)
   8:	df 48 8b             	fisttps -0x75(%rax)
   b:	54                   	push   %rsp
   c:	24 08                	and    $0x8,%al
   e:	49 89 d5             	mov    %rdx,%r13
  11:	49 89 d4             	mov    %rdx,%r12
  14:	49 c1 ed 03          	shr    $0x3,%r13
  18:	41 83 e4 07          	and    $0x7,%r12d
  1c:	49 01 c5             	add    %rax,%r13
  1f:	41 83 c4 03          	add    $0x3,%r12d
  23:	e8 69 83 0c 00       	call   0xc8391
  28:	f3 90                	pause
* 2a:	41 0f b6 45 00       	movzbl 0x0(%r13),%eax <-- trapping instruction
  2f:	41 38 c4             	cmp    %al,%r12b
  32:	7c 08                	jl     0x3c
  34:	84 c0                	test   %al,%al
  36:	0f 85 63 0f 00 00    	jne    0xf9f
  3c:	8b 45 08             	mov    0x8(%rbp),%eax
  3f:	31                   	.byte 0x31