rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-....: (1 GPs behind) idle=99f/1/0x4000000000000002 softirq=23371/23373 fqs=2099 (detected by 1, t=10502 jiffies, g=37653, q=1464) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10598 Comm: syz.0.3048 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:check_preemption_disabled+0x1/0x110 lib/smp_processor_id.c:13 Code: 00 48 c7 c7 20 e8 32 8a e8 2c 01 00 00 65 ff 0d a1 2b 47 76 5b c3 00 00 cc 48 c7 c7 e0 f6 79 8a 48 c7 c6 20 f7 79 8a eb 00 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 RSP: 0018:ffffc90000006f78 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffff88807a643b80 RDX: 0000000000000100 RSI: ffffffff8a79f720 RDI: ffffffff8a79f6e0 RBP: 0000000000000001 R08: ffffc90000007157 R09: ffffc90000007120 R10: dffffc0000000000 R11: fffff52000000e2b R12: dffffc0000000000 R13: ffffc90000007186 R14: ffffffff8c125da0 R15: dffffc0000000000 FS: 00007f07ffa406c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f080042a6c0 CR3: 00000000604f8000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline] rcu_is_watching+0x11/0xa0 kernel/rcu/tree.c:1123 rcu_read_lock_held_common kernel/rcu/update.c:108 [inline] rcu_read_lock_held+0x11/0x40 kernel/rcu/update.c:309 perf_get_guest_cbs include/linux/perf_event.h:1274 [inline] perf_misc_flags+0x56/0x1b0 arch/x86/events/core.c:2961 perf_prepare_sample+0x132/0x1cd0 kernel/events/core.c:7622 __perf_event_output kernel/events/core.c:7802 [inline] perf_event_output_forward+0x185/0x2e0 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_swevent_overflow kernel/events/core.c:9591 [inline] perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674 Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 e2 f0 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08 RSP: 0018:ffffc90000007780 EFLAGS: 00000206 RAX: f9688c892508b700 RBX: 1ffff92000000ef4 RCX: f9688c892508b700 RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f740 RBP: ffffc90000007860 R08: ffffffff901d215f R09: 1ffffffff203a42b R10: dffffc0000000000 R11: fffffbfff203a42c R12: ffffffff8c322f00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __ip_queue_xmit+0x1242/0x1c00 net/ipv4/ip_output.c:539 __tcp_transmit_skb+0x1d11/0x3200 net/ipv4/tcp_output.c:1404 tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314 tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x53a/0x7f0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x339/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:generic_exec_single+0x373/0x460 kernel/smp.c:532 Code: df eb 27 e8 7f 6c 0b 00 0f 0b e9 b6 fd ff ff e8 73 6c 0b 00 e8 6e 64 4e 08 48 85 db 0f 84 5c ff ff ff e8 60 6c 0b 00 fb 31 c0 <48> c7 44 24 20 0e 36 e0 45 4b c7 44 3d 00 00 00 00 00 43 c7 44 3d RSP: 0018:ffffc90004857a60 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000200 RCX: ffff88807a643b80 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90004857b30 R08: ffffffff901d20cf R09: 1ffffffff203a419 R10: dffffc0000000000 R11: fffffbfff203a41a R12: ffffc90004857b88 R13: 1ffff9200090af50 R14: 0000000000000000 R15: dffffc0000000000 smp_call_function_single+0x202/0x4c0 kernel/smp.c:755 cpu_function_call kernel/events/core.c:153 [inline] perf_install_in_context+0x528/0x920 kernel/events/core.c:2974 __do_sys_perf_event_open kernel/events/core.c:12793 [inline] __se_sys_perf_event_open+0x12b3/0x1bb0 kernel/events/core.c:12387 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f08003dcf79 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:00007f07ffa40028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f0800657fa0 RCX: 00007f08003dcf79 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 00002000000003c0 RBP: 00007f08004736e0 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0800658038 R14: 00007f0800657fa0 R15: 00007ffc10951968