------------[ cut here ]------------ WARNING: CPU: 0 PID: 70 at kernel/rcu/tree_stall.h:1050 rcu_check_gp_start_stall+0x2e4/0x470 kernel/rcu/tree_stall.h:1050 Modules linked in: CPU: 0 UID: 0 PID: 70 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:rcu_check_gp_start_stall+0x2e4/0x470 kernel/rcu/tree_stall.h:1050 Code: ff ff 48 c7 c7 60 d4 58 99 be 04 00 00 00 e8 93 73 7e 00 4c 89 f7 b8 01 00 00 00 87 05 15 23 b3 17 85 c0 0f 85 17 ff ff ff 90 <0f> 0b 90 48 81 ff 80 04 d4 8d 74 47 48 c7 c0 30 1d 5c 8f 48 c1 e8 RSP: 0018:ffffc90000007bb8 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000a02 RCX: ffffffff81a5b13d RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8dd40480 RBP: ffffc90000007e30 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff32b1a8c R12: 0000000000002904 R13: 1ffff110171075fa R14: ffffffff8dd40480 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff88812638a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f826c7e7dac CR3: 000000000db36000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_core+0x5fa/0x1770 kernel/rcu/tree.c:2856 handle_softirqs+0x283/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 96 73 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 41 6f 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 25 6f RSP: 0018:ffffc9000216f660 EFLAGS: 00000293 RAX: ffffffff81b3103b RBX: 1ffff11017127ff5 RCX: ffff88801c30dac0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000216f7e0 R08: ffffffff8f5bed37 R09: 1ffffffff1eb7da6 R10: dffffc0000000000 R11: fffffbfff1eb7da7 R12: ffff8880b893ffa8 R13: dffffc0000000000 R14: ffff8880b883b200 R15: 0000000000000001 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:2653 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 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:852 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 45 8b 2c 24 mov (%r12),%r13d 4: 44 89 ee mov %r13d,%esi 7: 83 e6 01 and $0x1,%esi a: 31 ff xor %edi,%edi c: e8 96 73 0b 00 call 0xb73a7 11: 41 83 e5 01 and $0x1,%r13d 15: 49 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%r13 1c: fc ff df 1f: 75 07 jne 0x28 21: e8 41 6f 0b 00 call 0xb6f67 26: eb 38 jmp 0x60 28: f3 90 pause * 2a: 42 0f b6 04 2b movzbl (%rbx,%r13,1),%eax <-- trapping instruction 2f: 84 c0 test %al,%al 31: 75 11 jne 0x44 33: 41 f7 04 24 01 00 00 testl $0x1,(%r12) 3a: 00 3b: 74 1e je 0x5b 3d: e8 .byte 0xe8 3e: 25 .byte 0x25 3f: 6f outsl %ds:(%rsi),(%dx)