Re: [syzbot] INFO: task hung in __input_unregister_device (4)

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

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On sabato 2 luglio 2022 17:32:22 CEST syzbot wrote:
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    90557fa89d3e dt-bindings: usb: atmel: Add Microchip 
LAN966..
> git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/
usb.git usb-testing
> console output: https://syzkaller.appspot.com/x/log.txt?x=16892484080000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=33f1eaa5b20a699
> dashboard link: https://syzkaller.appspot.com/bug?
extid=deb6abc36aad4008f407
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU 
Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?
x=155cc25c080000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11f64834080000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the 
commit:
> Reported-by: syzbot+deb6abc36aad4008f407@syzkaller.appspotmail.com
> 
> INFO: task kworker/0:2:71 blocked for more than 143 seconds.
>       Not tainted 5.19.0-rc4-syzkaller-00099-g90557fa89d3e #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/0:2     state:D stack:23752 pid:   71 ppid:     2 flags:
0x00004000
> Workqueue: usb_hub_wq hub_event
> Call Trace:
>  <TASK>
>  context_switch kernel/sched/core.c:5146 [inline]
>  __schedule+0x93f/0x2630 kernel/sched/core.c:6458
>  schedule+0xd2/0x1f0 kernel/sched/core.c:6530
>  schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6589
>  __mutex_lock_common kernel/locking/mutex.c:679 [inline]
>  __mutex_lock+0xa70/0x1350 kernel/locking/mutex.c:747
>  input_disconnect_device drivers/input/input.c:784 [inline]
>  __input_unregister_device+0x24/0x470 drivers/input/input.c:2234
>  input_unregister_device+0xb4/0xf0 drivers/input/input.c:2429
>  iforce_usb_disconnect+0x5e/0xf0 drivers/input/joystick/iforce/iforce-
usb.c:261
>  usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
>  device_remove drivers/base/dd.c:545 [inline]
>  device_remove+0x11f/0x170 drivers/base/dd.c:537
>  __device_release_driver drivers/base/dd.c:1222 [inline]
>  device_release_driver_internal+0x4a1/0x700 drivers/base/dd.c:1248
>  bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:529
>  device_del+0x4f3/0xc80 drivers/base/core.c:3604
>  usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1419
>  usb_disconnect.cold+0x278/0x6ec drivers/usb/core/hub.c:2228
>  hub_port_connect drivers/usb/core/hub.c:5190 [inline]
>  hub_port_connect_change drivers/usb/core/hub.c:5490 [inline]
>  port_event drivers/usb/core/hub.c:5646 [inline]
>  hub_event+0x1e83/0x4690 drivers/usb/core/hub.c:5728
>  process_one_work+0x996/0x1610 kernel/workqueue.c:2289
>  process_scheduled_works kernel/workqueue.c:2352 [inline]
>  worker_thread+0x854/0x1080 kernel/workqueue.c:2438
>  kthread+0x2ef/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
>  </TASK>
> 
> Showing all locks held in the system:
> 1 lock held by khungtaskd/26:
>  #0: ffffffff87a94700 (rcu_read_lock){....}-{1:2}, at: 
debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6491
> 6 locks held by kworker/0:2/71:
>  #0: ffff888109b13538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: 
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
>  #0: ffff888109b13538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: 
arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
>  #0: ffff888109b13538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: 
atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
>  #0: ffff888109b13538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: 
set_work_data kernel/workqueue.c:636 [inline]
>  #0: ffff888109b13538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: 
set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
>  #0: ffff888109b13538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: 
process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
>  #1: ffffc90001057da8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: 
process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
>  #2: ffff88810f267190 (&dev->mutex){....}-{3:3}, at: device_lock include/
linux/device.h:835 [inline]
>  #2: ffff88810f267190 (&dev->mutex){....}-{3:3}, at: 
hub_event+0x1c1/0x4690 drivers/usb/core/hub.c:5674
>  #3: ffff88811d2ca190 (&dev->mutex){....}-{3:3}, at: device_lock include/
linux/device.h:835 [inline]
>  #3: ffff88811d2ca190 (&dev->mutex){....}-{3:3}, at: 
usb_disconnect.cold+0x43/0x6ec drivers/usb/core/hub.c:2219
>  #4: ffff88811d2cb118 (&dev->mutex){....}-{3:3}, at: device_lock include/
linux/device.h:835 [inline]
>  #4: ffff88811d2cb118 (&dev->mutex){....}-{3:3}, at: __device_driver_lock 
drivers/base/dd.c:1054 [inline]
>  #4: ffff88811d2cb118 (&dev->mutex){....}-{3:3}, at: 
device_release_driver_internal+0xa0/0x700 drivers/base/dd.c:1245
>  #5: ffff88811d2cc2c0 (&dev->mutex#2){+.+.}-{3:3}, at: 
input_disconnect_device drivers/input/input.c:784 [inline]
>  #5: ffff88811d2cc2c0 (&dev->mutex#2){+.+.}-{3:3}, at: 
__input_unregister_device+0x24/0x470 drivers/input/input.c:2234
> 2 locks held by acpid/1166:
>  #0: ffff88811d2cf110 (&evdev->mutex){+.+.}-{3:3}, at: evdev_close_device 
drivers/input/evdev.c:411 [inline]
>  #0: ffff88811d2cf110 (&evdev->mutex){+.+.}-{3:3}, at: 
evdev_release+0x299/0x410 drivers/input/evdev.c:456
>  #1: ffff88811d2cc2c0 (&dev->mutex#2){+.+.}-{3:3}, at: 
input_close_device+0x42/0x1f0 drivers/input/input.c:726
> 2 locks held by getty/1240:
>  #0: ffff8881109fc098 (&tty->ldisc_sem){++++}-{0:0}, at: 
tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
>  #1: ffffc900000432e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: 
n_tty_read+0xe50/0x13c0 drivers/tty/n_tty.c:2124
> 3 locks held by udevd/1293:
>  #0: ffff8881106e6488 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter 
fs/kernfs/file.c:197 [inline]
>  #0: ffff8881106e6488 (&of->mutex){+.+.}-{3:3}, at: 
kernfs_fop_read_iter+0x189/0x6e0 fs/kernfs/file.c:236
>  #1: ffff888108bf0a00 (kn->active#40){++++}-{0:0}, at: 
kernfs_file_read_iter fs/kernfs/file.c:198 [inline]
>  #1: ffff888108bf0a00 (kn->active#40){++++}-{0:0}, at: 
kernfs_fop_read_iter+0x1ac/0x6e0 fs/kernfs/file.c:236
>  #2: ffff88811d2ca190 (&dev->mutex){....}-{3:3}, at: 
device_lock_interruptible include/linux/device.h:840 [inline]
>  #2: ffff88811d2ca190 (&dev->mutex){....}-{3:3}, at: 
read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
> 
> =============================================
> 
> NMI backtrace for cpu 0
> CPU: 0 PID: 26 Comm: khungtaskd Not tainted 5.19.0-rc4-syzkaller-00099-
g90557fa89d3e #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS 
Google 06/29/2022
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
>  nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
>  nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62
>  trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
>  check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
>  watchdog+0xc1d/0xf50 kernel/hung_task.c:369
>  kthread+0x2ef/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
>  </TASK>
> Sending NMI from CPU 0 to CPUs 1:
> NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/
include/asm/irqflags.h:51 [inline]
> NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/
include/asm/irqflags.h:89 [inline]
> NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt drivers/acpi/
processor_idle.c:111 [inline]
> NMI backtrace for cpu 1 skipped: idling at acpi_idle_do_entry+0x1c9/0x240 
drivers/acpi/processor_idle.c:554
> 
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> 
#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 
usb-testing

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diff --git a/drivers/input/joystick/iforce/iforce-usb.c b/drivers/input/joystick/iforce/iforce-usb.c
index ea58805c480f..2717e35c79a3 100644
--- a/drivers/input/joystick/iforce/iforce-usb.c
+++ b/drivers/input/joystick/iforce/iforce-usb.c
@@ -258,6 +258,9 @@ static void iforce_usb_disconnect(struct usb_interface *intf)
 
 	usb_set_intfdata(intf, NULL);
 
+	clear_bit(IFORCE_XMIT_RUNNING, iforce_usb->iforce.xmit_flags);
+	wake_up(&iforce_usb->iforce.wait);
+
 	input_unregister_device(iforce_usb->iforce.dev);
 
 	usb_free_urb(iforce_usb->irq);