Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock

From	Jiri Kosina <jikos@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock
Date	2015-11-19 10:20 +0100
Message-ID	<qwtxM-7n4-21@gated-at.bofh.it> (permalink)
References	<qwgAz-7es-25@gated-at.bofh.it> <qwhGh-7Ze-3@gated-at.bofh.it> <qwi9j-8vZ-7@gated-at.bofh.it> <qwkNQ-1An-19@gated-at.bofh.it> <qwrcC-5Lq-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Thu, 19 Nov 2015, Ioan-Adrian Ratiu wrote:

> First part of lockdep report:
> http://imgur.com/clLsCWe
> 
> Second part:
> http://imgur.com/Wa2PzRl
> 
> Here are some printk's of mine while reproducing + debugging the issue:
> http://imgur.com/SETOHT7

So the real problem is that Intuos driver is calling hid_hw_request() 
(which tries to grab the lock in usbhid_submit_report()) while handling 
the CTRL IRQ (lock gets acquired there).

So the proper way to fix seems to be delaying the scheduling of the 
proximity read event in wacom_intuos_inout() to workqueue.

> I'll continue to research this more in depth, but progress is slow 
> because I don't have much time, I'm doing this in my spare time because 
> it's my girlfriend's tablet.

Oh, now I understand the level of severity of this bug! :-)

Thanks,

-- 
Jiri Kosina
SUSE Labs

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Thread

[PATCH] hid: usbhid: hid-core: fix recursive deadlock Ioan-Adrian Ratiu <adi@adirat.com> - 2015-11-18 20:30 +0100
  Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Jiri Kosina <jikos@kernel.org> - 2015-11-18 21:40 +0100
    Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Ioan-Adrian Ratiu <adi@adirat.com> - 2015-11-18 22:10 +0100
      Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Josh Cartwright <joshc@ni.com> - 2015-11-19 01:00 +0100
        Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Ioan-Adrian Ratiu <adi@adirat.com> - 2015-11-19 07:50 +0100
          Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Jiri Kosina <jikos@kernel.org> - 2015-11-19 10:20 +0100
            Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Ioan-Adrian Ratiu <adi@adirat.com> - 2015-11-19 17:40 +0100
              Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Jiri Kosina <jikos@kernel.org> - 2015-11-19 22:40 +0100
                Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Ioan-Adrian Ratiu <adi@adirat.com> - 2015-11-20 21:10 +0100
      Re: [PATCH] hid: usbhid: hid-core: fix recursive deadlock Jiri Kosina <jikos@kernel.org> - 2015-11-19 10:00 +0100
  [PATCH v2] hid: usbhid: hid-core: fix recursive deadlock Ioan-Adrian Ratiu <adi@adirat.com> - 2015-11-20 21:20 +0100
    Re: [PATCH v2] hid: usbhid: hid-core: fix recursive deadlock Ioan-Adrian Ratiu <adi@adirat.com> - 2015-11-29 11:30 +0100

csiph-web