rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (1 GPs behind) idle=3d5/1/0x4000000000000000 softirq=20379/20382 fqs=5247 (t=10502 jiffies g=27453 q=672) NMI backtrace for cpu 1 CPU: 1 PID: 7440 Comm: syz.3.635 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349 print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x6ea/0x1120 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:2021 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4b4/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202 Code: 66 2e 0f 1f 84 00 00 00 00 00 53 48 89 fb e8 17 00 00 00 48 8b 3d 90 c4 10 0c 48 89 de 5b e9 b7 41 44 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d a4 4e 89 7e 65 8b 15 a5 4e 89 7e 81 e2 00 RSP: 0018:ffffc90000dd0298 EFLAGS: 00000287 RAX: ffffffff88146306 RBX: 00000000000011e0 RCX: ffff88807e24d940 RDX: 0000000000000100 RSI: 00000000000008ef RDI: 0000000000000fff RBP: 00000000000008ef R08: ffffffff901d418f R09: 1ffffffff203a831 R10: dffffc0000000000 R11: fffffbfff203a832 R12: 0000000000000000 R13: 00000000000008ef R14: 00000000000008ef R15: ffff888032cc769c cake_heap_get_backlog net/sched/sch_cake.c:1470 [inline] cake_heapify+0x1dd/0x6a0 net/sched/sch_cake.c:1495 cake_drop net/sched/sch_cake.c:1575 [inline] cake_enqueue+0x33d9/0x7fc0 net/sched/sch_cake.c:1949 dev_qdisc_enqueue+0x48/0x210 net/core/dev.c:3865 __dev_xmit_skb net/core/dev.c:3949 [inline] __dev_queue_xmit+0xc25/0x2f80 net/core/dev.c:4266 tipc_l2_send_msg+0x30a/0x3c0 net/tipc/bearer.c:518 tipc_bearer_xmit_skb+0x292/0x3c0 net/tipc/bearer.c:577 tipc_disc_timeout+0x57d/0x6d0 net/tipc/discover.c:338 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648 expire_timers kernel/time/timer.c:1699 [inline] __run_timers+0x53e/0x800 kernel/time/timer.c:1970 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983 handle_softirqs+0x339/0x830 kernel/softirq.c:576 do_softirq+0x142/0x210 kernel/softirq.c:477 __local_bh_enable_ip+0x180/0x1c0 kernel/softirq.c:401 lock_sock include/net/sock.h:1744 [inline] skcipher_recvmsg+0xc0/0xd60 crypto/algif_skcipher.c:155 ____sys_recvmsg+0x2cd/0x5e0 net/socket.c:-1 ___sys_recvmsg+0x21a/0x5c0 net/socket.c:2706 do_recvmmsg+0x382/0x850 net/socket.c:2800 __sys_recvmmsg net/socket.c:2879 [inline] __do_sys_recvmmsg net/socket.c:2902 [inline] __se_sys_recvmmsg net/socket.c:2895 [inline] __x64_sys_recvmmsg+0x195/0x250 net/socket.c:2895 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: 0033:0x7fc8ce5f4819 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:00007fc8cc84e028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fc8ce86dfa0 RCX: 00007fc8ce5f4819 RDX: 03ffffffffffff67 RSI: 0000200000002440 RDI: 0000000000000004 RBP: 00007fc8ce68ac91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc8ce86e038 R14: 00007fc8ce86dfa0 R15: 00007ffc50e83ec8