syzbot

 sign-in | mailing list | source | docs
🐞 Open [1429]
≡ Subsystems
🐞 Fixed [6918]
🐞 Invalid [18005]
⬇ Missing Backports [223]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
💬 Send us feedback

INFO: rcu detected stall in dummy_timer (2)

Status: auto-closed as invalid on 2020/02/09 05:37
Subsystems: usb
[Documentation on labels]
First crash: 2286d, last: 2286d
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in dummy_timer (4) usb 1 C inconclusive done 25 153d 1315d 29/29 fixed on 2025/11/14 12:00
linux-5.15 INFO: rcu detected stall in dummy_timer 1 C error 6 119d 1026d 0/3 auto-obsoleted due to no activity on 2026/01/24 13:15
upstream INFO: rcu detected stall in dummy_timer (3) usb 1 C error 132 1451d 2039d 20/29 fixed on 2022/03/08 16:11
upstream INFO: rcu detected stall in dummy_timer usb 1 C 16 2315d 2379d 13/29 fixed on 2019/10/27 22:28

Sample crash report:
cdc_wdm 3-1:118.0: nonzero urb status received: -71
cdc_wdm 3-1:118.0: wdm_int_callback - 0 bytes
cdc_wdm 3-1:118.0: nonzero urb status received: -71
cdc_wdm 3-1:118.0: wdm_int_callback - 0 bytes
imon 5-1:0.0: imon usb_rx_callback_intf0: status(-71): ignored
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 	1-....: (1 GPs behind) idle=8f6/1/0x4000000000000004 softirq=14506/14507 fqs=5221 
	(t=10500 jiffies g=23761 q=215)
NMI backtrace for cpu 1
CPU: 1 PID: 3036 Comm: kworker/1:6 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xca/0x13e lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x55/0x96 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b0/0x1c7 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x169/0x1b3 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:2795 [inline]
 rcu_sched_clock_irq.cold+0x4da/0x936 kernel/rcu/tree.c:2244
 update_process_times+0x25/0x60 kernel/time/timer.c:1726
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:167
 tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1299
 __run_hrtimer kernel/time/hrtimer.c:1514 [inline]
 __hrtimer_run_queues+0x303/0xc60 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x2e8/0x730 kernel/time/hrtimer.c:1638
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xf5/0x500 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x40/0x50 kernel/locking/spinlock.c:191
Code: e8 d5 ea b5 fb 48 89 ef e8 ad c9 b6 fb f6 c7 02 75 11 53 9d e8 c1 9d d3 fb 65 ff 0d 02 3d 92 7a 5b 5d c3 e8 62 a1 d3 fb 53 9d <eb> ed 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 fd 65 ff
RSP: 0018:ffff8881db309b08 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: 0000000000000206 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881cd46a04c
RBP: ffff8881d5094000 R08: ffff8881cd469800 R09: fffffbfff11ab3b6
R10: fffffbfff11ab3b5 R11: ffffffff88d59daf R12: 0000000000000200
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8881ce6fd400
 spin_unlock_irqrestore include/linux/spinlock.h:393 [inline]
 dummy_timer+0x1349/0x2fdb drivers/usb/gadget/udc/dummy_hcd.c:1980
 call_timer_fn+0x179/0x650 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x5e3/0x1490 kernel/time/timer.c:1786
 __do_softirq+0x221/0x912 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x178/0x1a0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x12f/0x500 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 </IRQ>
RIP: 0010:lock_is_held_type+0x1ce/0x240 kernel/locking/lockdep.c:4530
Code: 89 f9 48 c1 e9 03 0f b6 0c 11 48 89 fa 83 e2 07 83 c2 03 38 ca 7c 04 84 c9 75 6e c7 83 4c 08 00 00 00 00 00 00 ff 74 24 08 9d <48> 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 31 c0 eb a8 48 83 c4
RSP: 0018:ffff8881afb47578 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffff8881cd469800 RCX: 0000000000000000
RDX: 0000000000000007 RSI: ffffffff86cfe8a0 RDI: ffff8881cd46a04c
RBP: ffff8881cd469800 R08: ffffffff88d17c90 R09: fffffbfff0f0cb51
R10: fffffbfff0f0cb50 R11: ffffffff87865a87 R12: ffff8881cd46a048
R13: ffffed1039a8d409 R14: ffffffff86cfe8a0 R15: ffff8881cd46a0f0
 lock_is_held include/linux/lockdep.h:362 [inline]
 rcu_preempt_sleep_check include/linux/rcupdate.h:272 [inline]
 ___might_sleep+0x1c5/0x2b0 kernel/sched/core.c:6745
 slab_pre_alloc_hook mm/slab.h:565 [inline]
 slab_alloc_node mm/slub.c:2703 [inline]
 kmem_cache_alloc_node+0x270/0x310 mm/slub.c:2815
 __alloc_skb+0xba/0x5a0 net/core/skbuff.c:197
 alloc_skb include/linux/skbuff.h:1049 [inline]
 alloc_uevent_skb+0x7b/0x210 lib/kobject_uevent.c:289
 uevent_net_broadcast_untagged lib/kobject_uevent.c:325 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:408 [inline]
 kobject_uevent_env+0x8ee/0x1160 lib/kobject_uevent.c:592
 driver_bound+0x197/0x1f0 drivers/base/dd.c:394
 really_probe+0x358/0x6d0 drivers/base/dd.c:588
 driver_probe_device+0x104/0x210 drivers/base/dd.c:721
 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
 __device_attach+0x217/0x360 drivers/base/dd.c:894
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
 device_add+0xae6/0x16f0 drivers/base/core.c:2202
 usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2537
 hub_port_connect drivers/usb/core/hub.c:5184 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
 port_event drivers/usb/core/hub.c:5470 [inline]
 hub_event+0x1df8/0x3800 drivers/usb/core/hub.c:5552
 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x318/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
cdc_wdm 3-1:118.0: nonzero urb status received: -71
cdc_wdm 3-1:118.0: wdm_int_callback - 0 bytes
imon 5-1:0.0: imon usb_rx_callback_intf0: status(-71): ignored
cdc_wdm 3-1:118.0: nonzero urb status received: -71
cdc_wdm 3-1:118.0: wdm_int_callback - 0 bytes
cdc_wdm 3-1:118.0: wdm_int_callback - usb_submit_urb failed with result -19

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/11/11 05:34 https://github.com/google/kasan.git usb-fuzzer 3183c03757f8 dc438b91 .config console log report ci2-upstream-usb
* Struck through repros no longer work on HEAD.