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1
WARNING: kernel/rcu/tree_stall.h:1048 at rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1048, CPU#1: kworker/u8:10/3365
Modules linked in:
CPU: 1 UID: 0 PID: 3365 Comm: kworker/u8:10 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1048
Code: 88 61 01 00 00 be 04 00 00 00 48 c7 c7 80 d5 72 9b e8 60 1b 8c 00 b8 01 00 00 00 87 05 75 a3 84 19 85 c0 0f 85 3d 01 00 00 90 <0f> 0b 90 48 c7 c3 64 59 22 91 48 81 fd 40 14 bf 8e 74 5a 48 b8 00
RSP: 0018:ffffc90000a08df0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000002904 RCX: ffffffff81ee3200
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff9b72d580
RBP: ffffffff8ebf1440 R08: 0000000000000001 R09: fffffbfff36e5ab0
R10: 0000000000000003 R11: 0000000000000000 R12: 1ffffffff1d01e50
R13: 0000000000000246 R14: 0000000000000020 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888123eec000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000009b40 CR3: 000000000e992000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:1011 [inline]
 rcu_core+0x2cb/0x10d0 kernel/rcu/tree.c:2892
 handle_softirqs+0x1ea/0x9b0 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:1062 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline]
RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:246
Code: 6d fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <65> 8b 05 d9 76 59 12 49 89 f8 49 89 f1 49 89 d2 65 48 8b 3d b0 76
RSP: 0018:ffffc9000e127870 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81fd3b0d
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000005
RBP: ffff8880b8443680 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170886d1 R14: 0000000000000001 R15: ffff8880b853c880
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0x5ad/0x16c0 kernel/smp.c:892
 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:911 [inline]
 toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:903
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 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), 3 bytes skipped:
   0:	ff 66 2e             	jmp    *0x2e(%rsi)
   3:	0f 1f 84 00 00 00 00 	nopl   0x0(%rax,%rax,1)
   a:	00
   b:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  12:	00 00 00
  15:	66 90                	xchg   %ax,%ax
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	90                   	nop
  21:	90                   	nop
  22:	90                   	nop
  23:	90                   	nop
  24:	90                   	nop
  25:	90                   	nop
  26:	90                   	nop
* 27:	65 8b 05 d9 76 59 12 	mov    %gs:0x125976d9(%rip),%eax        # 0x12597707 <-- trapping instruction
  2e:	49 89 f8             	mov    %rdi,%r8
  31:	49 89 f1             	mov    %rsi,%r9
  34:	49 89 d2             	mov    %rdx,%r10
  37:	65                   	gs
  38:	48                   	rex.W
  39:	8b                   	.byte 0x8b
  3a:	3d                   	.byte 0x3d
  3b:	b0 76                	mov    $0x76,%al