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

From: John Youn
Date: Fri Oct 16 2015 - 03:58:06 EST


On 10/15/2015 4:38 PM, Doug Anderson wrote:
> John,
>
> On Thu, Oct 15, 2015 at 4:21 PM, John Youn <John.Youn@xxxxxxxxxxxx> 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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