rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10499 ticks this GP) idle=17e/1/0x4000000000000002 softirq=237408/237408 fqs=5250 (t=10501 jiffies g=347933 q=401) NMI backtrace for cpu 0 CPU: 0 PID: 15239 Comm: syz-executor.0 Not tainted 5.5.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq.cold+0x509/0xc0d kernel/rcu/tree.c:2271 update_process_times+0x2d/0x70 kernel/time/timer.c:1726 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:171 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1314 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:__sanitizer_cov_trace_pc+0x3b/0x50 kernel/kcov.c:192 Code: 27 8d 7e 81 e2 00 01 1f 00 48 8b 75 08 75 2b 8b 90 80 13 00 00 83 fa 02 75 20 48 8b 88 88 13 00 00 8b 80 84 13 00 00 48 8b 11 <48> 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 RSP: 0018:ffffc90007997570 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc90001ee9000 RDX: 000000000003ffff RSI: ffffffff8644817e RDI: 0000000000000005 RBP: ffffc90007997570 R08: ffff88809ee18300 R09: fffffbfff165e7b5 R10: fffffbfff165e7b4 R11: ffffffff8b2f3da7 R12: ffff88809f116338 R13: ffff88809f116320 R14: dffffc0000000000 R15: ffff88809f116320 cbq_dequeue_prio net/sched/sch_cbq.c:700 [inline] cbq_dequeue_1 net/sched/sch_cbq.c:792 [inline] cbq_dequeue+0xc2e/0x22a0 net/sched/sch_cbq.c:816 dequeue_skb net/sched/sch_generic.c:263 [inline] qdisc_restart net/sched/sch_generic.c:366 [inline] __qdisc_run+0x1a5/0x1770 net/sched/sch_generic.c:384 __dev_xmit_skb net/core/dev.c:3677 [inline] __dev_queue_xmit+0x163f/0x35c0 net/core/dev.c:3982 dev_queue_xmit+0x18/0x20 net/core/dev.c:4046 packet_snd net/packet/af_packet.c:2966 [inline] packet_sendmsg+0x260d/0x6220 net/packet/af_packet.c:2991 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 sock_write_iter+0x2cb/0x400 net/socket.c:991 call_write_iter include/linux/fs.h:1902 [inline] new_sync_write+0x4d3/0x770 fs/read_write.c:483 __vfs_write+0xe1/0x110 fs/read_write.c:496 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x220/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __ia32_sys_write+0x71/0xb0 fs/read_write.c:620 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f7e9a9 Code: 00 00 00 89 d3 5b 5e 5f 5d c3 b8 80 96 98 00 eb c4 8b 04 24 c3 8b 1c 24 c3 8b 34 24 c3 8b 3c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f5d7a0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000300 RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000