Re: usb/gadget: stalls in dummy_timer

On Mon, Sep 11, 2017 at 3:25 PM, Alan Stern [off-list ref] wrote:

On Mon, 11 Sep 2017, Andrey Konovalov wrote:

quoted

Hi!

I've been getting stall reports like this one while fuzzing the USB
stack with gadgetfs. I'm wondering whether this is a bug in gadgetfs
or is this report induced by the changes I've made to the USB core
code. I didn't touch gadgetfs code though (except for adding a few
printk's).

I'm on commit 81a84ad3cb5711cec79f4dd53a4ce026b092c432

It's possible that this was caused by commit f16443a034c7 ("USB:
gadgetfs, dummy-hcd, net2280: fix locking for callbacks").  I've been
meaning to repair the commit but haven't done it yet.

Can you test with that commit reverted?  You may end up seeing other
problems instead -- the ones that commit was intended to solve -- but
perhaps the stalls won't occur.

So I've reverted both: the changes I made to USB core and the commit
you mentioned, still saw the stalls.

I've manged to find a way to reproduce this and now I'm not sure the
problem is actually in gadgetfs, it might be the usbtouchscreen
driver.

The crash log is below.

Thanks!

gadgetfs: bound to dummy_udc driver
usb 1-1: new full-speed USB device number 2 using dummy_hcd
gadgetfs: connected
gadgetfs: disconnected
gadgetfs: connected
usb 1-1: config 8 interface 0 altsetting 9 endpoint 0x8F has an
invalid bInterval 0, changing to 10
usb 1-1: config 8 interface 0 altsetting 9 endpoint 0x8F has invalid
maxpacket 839, setting to 64
usb 1-1: config 8 interface 0 altsetting 9 endpoint 0x7 has invalid
maxpacket 1839, setting to 64
usb 1-1: config 8 interface 0 has no altsetting 0
usb 1-1: New USB device found, idVendor=0403, idProduct=f9e9
usb 1-1: New USB device strings: Mfr=4, Product=8, SerialNumber=255
usb 1-1: Product: a
usb 1-1: Manufacturer: a
usb 1-1: SerialNumber: a
gadgetfs: configuration #8
input: a a as /devices/platform/dummy_hcd.0/usb1/1-1/1-1:8.0/input/input8
evbug: Connected device: input8 (a a at usb-dummy_hcd.0-1/input0)
kworker/0:0: page allocation failure: order:0,
mode:0x1280020(GFP_ATOMIC|__GFP_NOTRACK), nodemask=(null)
kworker/0:0 cpuset=/ mems_allowed=0
CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.13.0+ #93
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:16
 dump_stack+0x192/0x22c lib/dump_stack.c:52
 warn_alloc+0x28e/0x430 mm/page_alloc.c:3242
 __alloc_pages_slowpath+0x1bbc/0x2250 mm/page_alloc.c:4043
 __alloc_pages_nodemask+0x914/0xea0 mm/page_alloc.c:4135
 alloc_pages_current+0xbb/0x1f0 mm/mempolicy.c:1974
 alloc_pages ./include/linux/gfp.h:507
 alloc_slab_page mm/slub.c:1408
 allocate_slab mm/slub.c:1559
 new_slab+0x384/0x410 mm/slub.c:1638
 new_slab_objects mm/slub.c:2423
 ___slab_alloc+0x35d/0x4c0 mm/slub.c:2575
 __slab_alloc+0x20/0x40 mm/slub.c:2615
 slab_alloc_node mm/slub.c:2678
 slab_alloc mm/slub.c:2720
 kmem_cache_alloc_trace+0x14e/0x170 mm/slub.c:2737
 kmalloc ./include/linux/slab.h:493
 dummy_urb_enqueue+0xf3/0x970 drivers/usb/gadget/udc/dummy_hcd.c:1220
 usb_hcd_submit_urb+0x2d3/0x1d50 drivers/usb/core/hcd.c:1664
 usb_submit_urb+0x937/0x11d0 drivers/usb/core/urb.c:542
 usbtouch_irq+0x216/0x2e0 drivers/input/touchscreen/usbtouchscreen.c:1441
 __usb_hcd_giveback_urb+0x2a1/0x5b0 drivers/usb/core/hcd.c:1779
 usb_hcd_giveback_urb+0x34f/0x4d0 drivers/usb/core/hcd.c:1845
 dummy_timer+0xbda/0x38c0 drivers/usb/gadget/udc/dummy_hcd.c:1924
 call_timer_fn+0xba/0x390 kernel/time/timer.c:1281
 expire_timers kernel/time/timer.c:1320
 __run_timers+0x9d0/0xda0 kernel/time/timer.c:1620
 run_timer_softirq+0x51/0xb0 kernel/time/timer.c:1646
 __do_softirq+0x258/0x7ac kernel/softirq.c:284
 invoke_softirq kernel/softirq.c:364
 irq_exit+0x14e/0x180 kernel/softirq.c:405
 exiting_irq ./arch/x86/include/asm/apic.h:638
 smp_apic_timer_interrupt+0x7b/0xa0 arch/x86/kernel/apic/apic.c:1044
 apic_timer_interrupt+0x89/0x90
RIP: 0010:arch_local_irq_restore ./arch/x86/include/asm/paravirt.h:814
RIP: 0010:console_unlock+0x814/0xcd0 kernel/printk/printk.c:2247
RSP: 0018:ffff88006bdedd30 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff10
RAX: 1ffff1000d7bdbe8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1ffff1000d7bdbe0 RSI: ffffffff87f007c0 RDI: 0000000000000a06
RBP: ffff88006bdee0a8 R08: fffffbfff0fe0102 R09: fffffbfff0fe0102
R10: 0000000000000009 R11: fffffbfff0fe0101 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff82d15610
 </IRQ>
 vprintk_emit+0x567/0x5d0 kernel/printk/printk.c:1769
 vprintk_default+0x2d/0x40 kernel/printk/printk.c:1808
 vprintk_func+0x5c/0xd0 kernel/printk/printk_safe.c:382
 printk+0xcd/0xfe kernel/printk/printk.c:1841
 evbug_connect+0x1de/0x260 drivers/input/evbug.c:69
 input_attach_handler+0x59a/0x740 drivers/input/input.c:1002
 input_register_device+0xcb8/0xf90 drivers/input/input.c:2159
 usbtouch_probe+0x1372/0x1fe0 drivers/input/touchscreen/usbtouchscreen.c:1690
 usb_probe_interface+0x351/0x8d0 drivers/usb/core/driver.c:361
 really_probe drivers/base/dd.c:385
 driver_probe_device+0x610/0xa00 drivers/base/dd.c:529
 __device_attach_driver+0x230/0x290 drivers/base/dd.c:625
 bus_for_each_drv+0x15e/0x210 drivers/base/bus.c:463
 __device_attach+0x269/0x3c0 drivers/base/dd.c:682
 device_initial_probe+0x1f/0x30 drivers/base/dd.c:729
 bus_probe_device+0x1da/0x280 drivers/base/bus.c:523
 device_add+0xcf9/0x1640 drivers/base/core.c:1703
 usb_set_configuration+0x1064/0x1890 drivers/usb/core/message.c:1932
 generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
 usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
 really_probe drivers/base/dd.c:385
 driver_probe_device+0x610/0xa00 drivers/base/dd.c:529
 __device_attach_driver+0x230/0x290 drivers/base/dd.c:625
 bus_for_each_drv+0x15e/0x210 drivers/base/bus.c:463
 __device_attach+0x269/0x3c0 drivers/base/dd.c:682
 device_initial_probe+0x1f/0x30 drivers/base/dd.c:729
 bus_probe_device+0x1da/0x280 drivers/base/bus.c:523
 device_add+0xcf9/0x1640 drivers/base/core.c:1703
 usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
 hub_port_connect drivers/usb/core/hub.c:4890
 hub_port_connect_change drivers/usb/core/hub.c:4996
 port_event drivers/usb/core/hub.c:5102
 hub_event+0x23c8/0x37c0 drivers/usb/core/hub.c:5182
 process_one_work+0x9fb/0x1570 kernel/workqueue.c:2097
 worker_thread+0x1e4/0x1350 kernel/workqueue.c:2231
 kthread+0x324/0x3f0 kernel/kthread.c:231
 ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425
Mem-Info:
active_anon:3514 inactive_anon:44 isolated_anon:0
 active_file:3194 inactive_file:2879 isolated_file:0
 unevictable:0 dirty:1474 writeback:0 unstable:0
 slab_reclaimable:2749 slab_unreclaimable:379894
 mapped:19353 shmem:52 pagetables:363 bounce:0
 free:2071 free_pcp:247 free_cma:0
Node 0 active_anon:14056kB inactive_anon:176kB active_file:12776kB
inactive_file:11516kB unevictable:0kB isolated(anon):0kB
isolated(file):0kB mapped:77412kB dirty:5896kB writeback:0kB
shmem:208kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
Node 0 DMA free:6440kB min:48kB low:60kB high:72kB active_anon:0kB
inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB
writepending:0kB present:15992kB managed:15908kB mlocked:0kB
kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB
free_cma:0kB
lowmem_reserve[]: 0 1607 1607 1607
Node 0 DMA32 free:1844kB min:5104kB low:6748kB high:8392kB
active_anon:14056kB inactive_anon:176kB active_file:12776kB
inactive_file:11516kB unevictable:0kB writepending:5896kB
present:2080760kB managed:1650852kB mlocked:0kB kernel_stack:2976kB
pagetables:1452kB bounce:0kB free_pcp:988kB local_pcp:272kB
free_cma:0kB
lowmem_reserve[]: 0 0 0 0
Node 0 DMA: 0*4kB 1*8kB (U) 0*16kB 1*32kB (U) 0*64kB 0*128kB 1*256kB
(U) 0*512kB 0*1024kB 1*2048kB (M) 1*4096kB (M) = 6440kB
Node 0 DMA32: 43*4kB (UME) 8*8kB (UME) 4*16kB (ME) 0*32kB 3*64kB (UME)
1*128kB (E) 3*256kB (UE) 1*512kB (M) 0*1024kB 0*2048kB 0*4096kB =
1900kB
Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
6123 total pagecache pages
0 pages in swap cache
Swap cache stats: add 0, delete 0, find 0/0
Free swap  = 0kB
Total swap = 0kB
524188 pages RAM
0 pages HighMem/MovableOnly
107498 pages reserved
SLUB: Unable to allocate memory on node -1, gfp=0x1080020(GFP_ATOMIC)
  cache: kmalloc-128, object size: 128, buffer size: 192, default
order: 0, min order: 0
  node 0: slabs: 374152, objs: 7857192, free: 0
usbtouchscreen 1-1:8.0: usbtouch_irq - usb_submit_urb failed with result: -12
INFO: rcu_sched self-detected stall on CPU
0-...: (1 GPs behind) idle=b32/140000000000002/0 softirq=5716/5717 fqs=0
(t=71918 jiffies g=2055 c=2054 q=23)
rcu_sched kthread starved for 71918 jiffies! g2055 c2054 f0x0
RCU_GP_WAIT_FQS(3) ->state=0x1
rcu_sched       S18936     8      2 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2771
 __schedule+0x6fa/0x1780 kernel/sched/core.c:3332
 schedule+0x106/0x450 kernel/sched/core.c:3391
 schedule_timeout+0x1d8/0x440 kernel/time/timer.c:1743
 rcu_gp_kthread+0x1edd/0x47e0 kernel/rcu/tree.c:2242
INFO: rcu_sched detected stalls on CPUs/tasks:
0-...: (1 GPs behind) idle=b32/140000000000002/0 softirq=5716/5717 fqs=0

(detected by 1, t=71918 jiffies, g=2055, c=2054, q=23)
Sending NMI from CPU 1 to CPUs 0:
 kthread+0x324/0x3f0 kernel/kthread.c:231
 ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425
NMI backtrace for cpu 0
CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.13.0+ #93
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: usb_hub_wq hub_event
task: ffff88006bdc1a00 task.stack: ffff88006bde8000
RIP: 0010:down_trylock+0xaf/0x1a0 kernel/locking/semaphore.c:136
RSP: 0018:ffff88006c8057b0 EFLAGS: 00000802
RAX: ffff88006c805818 RBX: 1ffff1000d900af7 RCX: dffffc0000000000
RDX: 1ffff1000d900afb RSI: 0000000000000000 RDI: ffffffff870b7780
RBP: ffff88006c805900 R08: fffffbfff0fe33a3 R09: ffffffff87f19d15
R10: 0000000000000001 R11: fffffbfff0fe33a2 R12: dffffc0000000000
R13: ffff88006c8058d8 R14: ffffffff870b7780 R15: 0000000000000064
FS:  0000000000000000(0000) GS:ffff88006c800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006e30a0 CR3: 000000006b983000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 __down_trylock_console_sem.isra.20+0xd8/0x170 kernel/printk/printk.c:228
 console_trylock kernel/printk/printk.c:2077
 vprintk_emit+0x543/0x5d0 kernel/printk/printk.c:1768
 vprintk_default+0x2d/0x40 kernel/printk/printk.c:1808
 vprintk_func+0x5c/0xd0 kernel/printk/printk_safe.c:382
 printk+0xcd/0xfe kernel/printk/printk.c:1841
 printk_stack_address arch/x86/kernel/dumpstack.c:50
 show_trace_log_lvl+0x26c/0x340 arch/x86/kernel/dumpstack.c:142
 show_stack+0x34/0x50 arch/x86/kernel/dumpstack.c:176
 sched_show_task+0x521/0x650 kernel/sched/core.c:5138
 rcu_check_gp_kthread_starvation+0x2fc/0x353 kernel/rcu/tree.c:1368
 print_cpu_stall+0x3ad/0x6d0 kernel/rcu/tree.c:1534
 check_cpu_stall.isra.72+0x707/0xe90 kernel/rcu/tree.c:1604
 __rcu_pending kernel/rcu/tree.c:3457
 rcu_pending kernel/rcu/tree.c:3519
 rcu_check_callbacks+0x241/0xa50 kernel/rcu/tree.c:2861
 update_process_times+0x35/0x70 kernel/time/timer.c:1590
 tick_sched_handle+0xf5/0x160 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x120 kernel/time/tick-sched.c:1190
 __run_hrtimer kernel/time/hrtimer.c:1213
 __hrtimer_run_queues+0x3f4/0x970 kernel/time/hrtimer.c:1277
 hrtimer_interrupt+0x22a/0x720 kernel/time/hrtimer.c:1311
 local_apic_timer_interrupt+0x74/0xe0 arch/x86/kernel/apic/apic.c:1019
 smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:1043
 apic_timer_interrupt+0x89/0x90
RIP: 0010:arch_local_irq_restore ./arch/x86/include/asm/paravirt.h:814
RIP: 0010:__raw_spin_unlock_irqrestore ./include/linux/spinlock_api_smp.h:160
RIP: 0010:_raw_spin_unlock_irqrestore+0xf5/0x160 kernel/locking/spinlock.c:191
RSP: 0018:ffff88006c806c40 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff10
RAX: 1ffff1000d900d95 RBX: 1ffff1000d900d89 RCX: dffffc0000000000
RDX: dffffc0000000000 RSI: 0000000000000a06 RDI: 0000000000000a06
RBP: ffff88006c806d48 R08: fffffbfff0fe326e R09: ffffffff87f1936a
R10: ffff88006c806420 R11: fffffbfff0fe326d R12: 1ffff1000d900d9d
R13: 1ffff1000d900d8d R14: ffff88006796c200 R15: ffff8800679e5488
 spin_unlock_irqrestore ./include/linux/spinlock.h:354
 dummy_timer+0x1aa8/0x38c0 drivers/usb/gadget/udc/dummy_hcd.c:1938
 call_timer_fn+0xba/0x390 kernel/time/timer.c:1281
 expire_timers kernel/time/timer.c:1320
 __run_timers+0x9d0/0xda0 kernel/time/timer.c:1620
 run_timer_softirq+0x51/0xb0 kernel/time/timer.c:1646
 __do_softirq+0x258/0x7ac kernel/softirq.c:284
 invoke_softirq kernel/softirq.c:364
 irq_exit+0x14e/0x180 kernel/softirq.c:405
 exiting_irq ./arch/x86/include/asm/apic.h:638
 smp_apic_timer_interrupt+0x7b/0xa0 arch/x86/kernel/apic/apic.c:1044
 apic_timer_interrupt+0x89/0x90
RIP: 0
Lost 243 message(s)!
rcu_sched kthread starved for 71918 jiffies! g2055 c2054 f0x0
RCU_GP_WAIT_FQS(3) ->state=0x0
NMI backtrace for cpu 0
rcu_sched       R
CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.13.0+ #93
  running task
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 <IRQ>
18936     8      2 0x00000000
 __dump_stack lib/dump_stack.c:16
 dump_stack+0x192/0x22c lib/dump_stack.c:52
Call Trace:
 context_switch kernel/sched/core.c:2771
 __schedule+0x6fa/0x1780 kernel/sched/core.c:3332
 nmi_cpu_backtrace+0x1f5/0x220 lib/nmi_backtrace.c:102
 nmi_trigger_cpumask_backtrace+0x108/0x160 lib/nmi_backtrace.c:61
 schedule+0x106/0x450 kernel/sched/core.c:3391
 arch_trigger_cpumask_backtrace+0x19/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 trigger_single_cpu_backtrace ./include/linux/nmi.h:123
 rcu_dump_cpu_stacks+0x272/0x306 kernel/rcu/tree.c:1390
 schedule_timeout+0x1d8/0x440 kernel/time/timer.c:1743
 print_cpu_stall+0x3b5/0x6d0 kernel/rcu/tree.c:1536
 rcu_gp_kthread+0x1edd/0x47e0 kernel/rcu/tree.c:2242
 check_cpu_stall.isra.72+0x707/0xe90 kernel/rcu/tree.c:1604
 __rcu_pending kernel/rcu/tree.c:3457
 rcu_pending kernel/rcu/tree.c:3519
 rcu_check_callbacks+0x241/0xa50 kernel/rcu/tree.c:2861
 update_process_times+0x35/0x70 kernel/time/timer.c:1590
 tick_sched_handle+0xf5/0x160 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x120 kernel/time/tick-sched.c:1190
 __run_hrtimer kernel/time/hrtimer.c:1213
 __hrtimer_run_queues+0x3f4/0x970 kernel/time/hrtimer.c:1277
 hrtimer_interrupt+0x22a/0x720 kernel/time/hrtimer.c:1311
 local_apic_timer_interrupt+0x74/0xe0 arch/x86/kernel/apic/apic.c:1019
 smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:1043
 apic_timer_interrupt+0x89/0x90
RIP: 0010:arch_local_irq_restore ./arch/x86/include/asm/paravirt.h:814
RIP: 0010:__raw_spin_unlock_irqrestore ./include/linux/spinlock_api_smp.h:160
RIP: 0010:_raw_spin_unlock_irqrestore+0xf5/0x160 kernel/locking/spinlock.c:191
RSP: 0018:ffff88006c806c40 EFLAGS: 00000a06
 ORIG_RAX: ffffffffffffff10
RAX: 1ffff1000d900d95 RBX: 1ffff1000d900d89 RCX: dffffc0000000000
RDX: dffffc0000000000 RSI: 0000000000000a06 RDI: 0000000000000a06
RBP: ffff88006c806d48 R08: fffffbfff0fe326e R09: ffffffff87f1936a
R10: ffff88006c806420 R11: fffffbfff0fe326d R12: 1ffff1000d900d9d
R13: 1ffff1000d900d8d R14: ffff88006796c200 R15: ffff8800679e5488
 kthread+0x324/0x3f0 kernel/kthread.c:231
 spin_unlock_irqrestore ./include/linux/spinlock.h:354
 dummy_timer+0x1aa8/0x38c0 drivers/usb/gadget/udc/dummy_hcd.c:1938
 ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425
 call_timer_fn+0xba/0x390 kernel/time/timer.c:1281
 expire_timers kernel/time/timer.c:1320
 __run_timers+0x9d0/0xda0 kernel/time/timer.c:1620
 run_timer_softirq+0x51/0xb0 kernel/time/timer.c:1646
 __do_softirq+0x258/0x7ac kernel/softirq.c:284
 invoke_softirq kernel/softirq.c:364
 irq_exit+0x14e/0x180 kernel/softirq.c:405
 exiting_irq ./arch/x86/include/asm/apic.h:638
 smp_apic_timer_interrupt+0x7b/0xa0 arch/x86/kernel/apic/apic.c:1044
 apic_timer_interrupt+0x89/0x90
RIP: 0010:arch_local_irq_restore ./arch/x86/include/asm/paravirt.h:814
RIP: 0010:console_unlock+0x814/0xcd0 kernel/printk/printk.c:2247
RSP: 0018:ffff88006bdedd30 EFLAGS: 00000a06 ORIG_RAX: ffffffffffffff10
RAX: 1ffff1000d7bdbe8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1ffff1000d7bdbe0 RSI: ffffffff87f007c0 RDI: 0000000000000a06
RBP: ffff88006bdee0a8 R08: fffffbfff0fe0102 R09: fffffbfff0fe0102
R10: 0000000000000009 R11: fffffbfff0fe0101 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff82d15610
 </IRQ>
 vprintk_emit+0x567/0x5d0 kernel/printk/printk.c:1769
 vprintk_default+0x2d/0x40 kernel/printk/printk.c:1808
 vprintk_func+0x5c/0xd0 kernel/printk/printk_safe.c:382
 printk+0xcd/0xfe kernel/printk/printk.c:1841
 evbug_connect+0x1de/0x260 drivers/input/evbug.c:69
 input_attach_handler+0x59a/0x740 drivers/input/input.c:1002
 input_register_device+0xcb8/0xf90 drivers/input/input.c:2159
 usbtouch_probe+0x1372/0x1fe0 drivers/input/touchscreen/usbtouchscreen.c:1690
 usb_probe_interface+0x351/0x8d0 drivers/usb/core/driver.c:361
 really_probe drivers/base/dd.c:385
 driver_probe_device+0x610/0xa00 drivers/base/dd.c:529
 __device_attach_driver+0x230/0x290 drivers/base/dd.c:625
 bus_for_each_drv+0x15e/0x210 drivers/base/bus.c:463
 __device_attach+0x269/0x3c0 drivers/base/dd.c:682
 device_initial_probe+0x1f/0x30 drivers/base/dd.c:729
 bus_probe_device+0x1da/0x280 drivers/base/bus.c:523
 device_add+0xcf9/0x1640 drivers/base/core.c:1703
 usb_set_configuration+0x1064/0x1890 drivers/usb/core/message.c:1932
 generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
 usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
 really_probe drivers/base/dd.c:385
 driver_probe_device+0x610/0xa00 drivers/base/dd.c:529
 __device_attach_driver+0x230/0x290 drivers/base/dd.c:625
 bus_for_each_drv+0x15e/0x210 drivers/base/bus.c:463
 __device_attach+0x269/0x3c0 drivers/base/dd.c:682
 device_initial_probe+0x1f/0x30 drivers/base/dd.c:729
 bus_probe_device+0x1da/0x280 drivers/base/bus.c:523
 device_add+0xcf9/0x1640 drivers/base/core.c:1703
 usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
 hub_port_connect drivers/usb/core/hub.c:4890
 hub_port_connect_change drivers/usb/core/hub.c:4996
 port_event drivers/usb/core/hub.c:5102
 hub_event+0x23c8/0x37c0 drivers/usb/core/hub.c:5182
 process_one_work+0x9fb/0x1570 kernel/workqueue.c:2097
 worker_thread+0x1e4/0x1350 kernel/workqueue.c:2231
 kthread+0x324/0x3f0 kernel/kthread.c:231
 ret_from_fork+0x25/0x30 arch/x86/entry/entry_64.S:425
dummy_hcd dummy_hcd.0: timer fired with no URBs pending?
gadgetfs: disconnected
usb 1-1: USB disconnect, device number 2
evbug: Disconnected device: input8