Re: [PATCH] xhci-ring: Fix Null pointer dereference

From: Alan Stern
Date: Mon Sep 01 2014 - 10:16:44 EST


On Mon, 1 Sep 2014, Mathias Nyman wrote:

> On 09/01/2014 12:36 PM, Ricardo Ribalda Delgado wrote:
> > After some time of use (one hour or so) my system started to behave
> > "weird". I did check dmesg and I was receiving the following line
> > again and again:
> >
> > usb-storage: Error in queuecommand_lck: us->sfb= ffff8805bd61ccc0

This is probably caused by some transfer not occurring correctly. With
a usbmon trace we could see what was going on.

> > I did disconnect the usb device and the whole computer crashed :S
> >
>
> Ok, thanks.
>
> Would you say things work better after the patch?
>
> I still think the patch solves part of the issue, i.e. how we handle halted endpoints
> in reset, but I don't know the reason why the endpoints stall in the first place

The endpoint stall occurs because the device's protocol requires the
endpoint to stall. The reason doesn't matter; xhci-hcd should handle
stalls correctly whenever they occur.

Alan Stern

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