------------[ cut here ]------------ WARNING: CPU: 0 PID: 29795 at kernel/rcu/tree_stall.h:1001 rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:993 Modules linked in: CPU: 0 PID: 29795 Comm: kworker/u4:4 Not tainted 6.6.101-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:1001 Code: ff ff ff 48 c7 c7 a0 c4 ee 96 be 04 00 00 00 e8 2a a8 6c 00 48 89 df b8 01 00 00 00 87 05 4c 8f 7e 15 85 c0 0f 85 19 ff ff ff <0f> 0b 48 81 ff 00 54 d3 8c 74 47 48 c7 c0 9c b9 4a 8e 48 c1 e8 03 RSP: 0018:ffffc90000007bb8 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffffffff8cd35400 RCX: ffffffff81703546 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8cd35400 RBP: ffffc90000007e30 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff2ddd894 R12: 0000000000002904 R13: 1ffff110171c7a6a R14: 0000000000000a02 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000002f5030 CR3: 000000000cb30000 CR4: 00000000003506f0 Call Trace: rcu_core+0x612/0x1720 kernel/rcu/tree.c:2462 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:check_kcov_mode kernel/kcov.c:184 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x30/0x60 kernel/kcov.c:216 Code: 04 24 65 48 8b 0d 60 24 7e 7e 65 8b 15 61 24 7e 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c <8b> 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 RSP: 0018:ffffc90004caf778 EFLAGS: 00000246 RAX: ffffffff817ac297 RBX: 1ffff110171e82f5 RCX: ffff88804c73bc00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90004caf900 R08: ffffffff90da3527 R09: 1ffffffff21b46a4 R10: dffffc0000000000 R11: fffffbfff21b46a5 R12: ffff8880b8f417a8 R13: dffffc0000000000 R14: ffff8880b8e3d588 R15: 0000000000000001 csd_lock_wait kernel/smp.c:311 [inline] smp_call_function_many_cond+0xdf7/0x1130 kernel/smp.c:855 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2222 [inline] text_poke_bp_batch+0x318/0x930 arch/x86/kernel/alternative.c:2432 text_poke_flush arch/x86/kernel/alternative.c:2623 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207 static_key_enable+0x1a/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xaa/0x250 mm/kfence/core.c:831 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 ---------------- Code disassembly (best guess): 0: 04 24 add $0x24,%al 2: 65 48 8b 0d 60 24 7e mov %gs:0x7e7e2460(%rip),%rcx # 0x7e7e246a 9: 7e a: 65 8b 15 61 24 7e 7e mov %gs:0x7e7e2461(%rip),%edx # 0x7e7e2472 11: 81 e2 00 01 ff 00 and $0xff0100,%edx 17: 74 11 je 0x2a 19: 81 fa 00 01 00 00 cmp $0x100,%edx 1f: 75 35 jne 0x56 21: 83 b9 1c 16 00 00 00 cmpl $0x0,0x161c(%rcx) 28: 74 2c je 0x56 * 2a: 8b 91 f8 15 00 00 mov 0x15f8(%rcx),%edx <-- trapping instruction 30: 83 fa 02 cmp $0x2,%edx 33: 75 21 jne 0x56 35: 48 8b 91 00 16 00 00 mov 0x1600(%rcx),%rdx 3c: 48 8b 32 mov (%rdx),%rsi 3f: 48 rex.W