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Re: [PATCH v2] usb: dwc2: host: Fix use after free w/ simultaneous irqs

From John Youn <John.Youn@synopsys.com>
Newsgroups linux.kernel
Subject Re: [PATCH v2] usb: dwc2: host: Fix use after free w/ simultaneous irqs
Date 2015-10-16 10:00 +0200
Message-ID <qk85I-8iu-33@gated-at.bofh.it> (permalink)
References <qjDbA-4sf-3@gated-at.bofh.it> <qk08a-4Qv-7@gated-at.bofh.it> <qk0hP-555-1@gated-at.bofh.it>
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On 10/15/2015 4:38 PM, Doug Anderson wrote:
> John,
> 
> On Thu, Oct 15, 2015 at 4:21 PM, John Youn <John.Youn@synopsys.com> wrote:
>> Passing a NULL qtd to some of the subcases will lead to a NULL
>> pointer dereference in that function or some function that it
>> calls.
>>
>> I think you could just check the qtd after each call and bail if
>> it's not ok.
> 
> I worry a little bit about ignoring an interrupt that we've already
> acknowledged, but if you think that's safer I can certainly change the
> patch.
> 

In terms of avoiding crashes it's probably safer.

Whether it is correct or not, I'm not sure. I need to review the
code more.

The question is: after the qtd has been freed, is anything the
other handlers do necessary? Might have to look at each case
separately.

John

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Thread

[PATCH v2] usb: dwc2: host: Fix use after free w/ simultaneous irqs Douglas Anderson <dianders@chromium.org> - 2015-10-15 01:00 +0200
  Re: [PATCH v2] usb: dwc2: host: Fix use after free w/ simultaneous  irqs John Youn <John.Youn@synopsys.com> - 2015-10-16 01:30 +0200
    Re: [PATCH v2] usb: dwc2: host: Fix use after free w/ simultaneous irqs Doug Anderson <dianders@chromium.org> - 2015-10-16 01:40 +0200
      Re: [PATCH v2] usb: dwc2: host: Fix use after free w/ simultaneous  irqs John Youn <John.Youn@synopsys.com> - 2015-10-16 10:00 +0200

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