syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=fdf/1/0x4000000000000000 softirq=28192/28193 fqs=5249 
	(t=10502 jiffies g=38833 q=621)
NMI backtrace for cpu 0
CPU: 0 PID: 4887 Comm: udevd Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 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+0x6d8/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 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:1690 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 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 c0 ac f1 0b 48 89 de 5b e9 77 99 43 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 94 ab 8a 7e 65 8b 15 95 ab 8a 7e 81 e2 00
RSP: 0018:ffffc90000007038 EFLAGS: 00000202
RAX: ffffffff88060f58 RBX: 0000000000000870 RCX: ffff888021cb8000
RDX: 0000000000000100 RSI: 0000000000000871 RDI: 0000000000000871
RBP: ffffc900000074f0 R08: dffffc0000000000 R09: fffffbfff1ff6e42
R10: fffffbfff1ff6e42 R11: 1ffffffff1ff6e41 R12: dffffc0000000000
R13: ffff88801e6e42d8 R14: ffff88801e6e02d0 R15: ffff88801e6e02c0
 cake_drop net/sched/sch_cake.c:1574 [inline]
 cake_enqueue+0x3071/0x7ee0 net/sched/sch_cake.c:1945
 qdisc_enqueue include/net/sch_generic.h:832 [inline]
 netem_dequeue+0xd39/0x1400 net/sched/sch_netem.c:737
 dequeue_skb net/sched/sch_generic.c:292 [inline]
 qdisc_restart net/sched/sch_generic.c:397 [inline]
 __qdisc_run+0x237/0x1480 net/sched/sch_generic.c:415
 __dev_xmit_skb net/core/dev.c:3942 [inline]
 __dev_queue_xmit+0xeb9/0x2ed0 net/core/dev.c:4253
 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+0x568/0x6b0 net/tipc/discover.c:338
 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
 expire_timers kernel/time/timer.c:1496 [inline]
 __run_timers+0x525/0x7c0 kernel/time/timer.c:1767
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
 handle_softirqs+0x328/0x820 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x12f/0x220 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
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:_raw_spin_lock_irq+0x1/0xe0 kernel/locking/spinlock.c:169
Code: 00 00 48 3b 44 24 48 75 10 4c 89 f0 48 8d 65 e0 5b 41 5c 41 5e 41 5f 5d c3 e8 6b 94 f6 ff 66 2e 0f 1f 84 00 00 00 00 00 90 55 <48> 89 e5 41 57 41 56 53 48 83 e4 e0 48 83 ec 60 48 89 fb 65 48 8b
RSP: 0018:ffffc90003e6f870 EFLAGS: 00000286
RAX: 0000000000000000 RBX: ffff888020270570 RCX: 1ffff920007cdef0
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff8c24d980
RBP: ffff8880202705e0 R08: dffffc0000000000 R09: fffff520007cdec9
R10: fffff520007cdec9 R11: 1ffff920007cdec8 R12: dffffc0000000000
R13: ffff888052cb3100 R14: ffff888052cb3160 R15: ffff888052cb3158
 spin_lock_irq include/linux/spinlock.h:388 [inline]
 kernfs_get_open_node fs/kernfs/file.c:530 [inline]
 kernfs_fop_open+0x99d/0xbf0 fs/kernfs/file.c:698
 do_dentry_open+0x7ff/0xf80 fs/open.c:826
 do_open fs/namei.c:3608 [inline]
 path_openat+0x2682/0x2f30 fs/namei.c:3742
 do_filp_open+0x1b3/0x3e0 fs/namei.c:3769
 do_sys_openat2+0x142/0x4a0 fs/open.c:1253
 do_sys_open fs/open.c:1269 [inline]
 __do_sys_openat fs/open.c:1285 [inline]
 __se_sys_openat fs/open.c:1280 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1280
 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: 0033:0x7f93f6f6b407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffd3bf0db50 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f93f6e7d880 RCX: 00007f93f6f6b407
RDX: 0000000000080000 RSI: 00007ffd3bf0dcd0 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000560e473f27f5
R13: 0000560e473f27f5 R14: 0000000000000001 R15: 0000560e4740d140
 </TASK>