On Thu, Mar 10, 2011 at 7:45 PM, Peter Hutterer <peter.hutte...@who-t.net>wrote:
> On Thu, Mar 10, 2011 at 05:51:34PM -0800, Ping Cheng wrote:
> > On Wed, Mar 2, 2011 at 10:06 PM, Peter Hutterer <
> peter.hutte...@who-t.net>wrote:
> >
> > > There is a small time window where a device may try to send an event
> even
> > > though it is not fully setup to send events yet, causing a server
> crash.
> > >
> > > This window opens when the tool is added to the list of devices in
> > > wcmParseOptions() and closes with the server calling
> xf86ActivateDevice().
> > > If an event for a dependent device is processed during that time, the
> tool
> > > will be available but the device pointer is still invalid.
> > >
> > > Crash can be reproduced by putting a breakpoint after wcmParseOptions()
> for
> > > the eraser, then generating events with the eraser. These will cause
> the
> > > tool to dereference tool->device->dev, which is uninitialized.
> > >
> > > Work around this with a simple "enabled" flag that is set whenever the
> tool
> > > is actually enabled.
> > >
> >
> > What's the plan for this patchset?
>
> have you seen the crash with this patch applied?
>
Well, I am not doing any of those extensive testing myself.
> I'm still waiting for the testing feedback.
No one is doing the testing for this driver in my sphere. The users are
still living in the old world.
> I've tested it with gdb, forcing
> some race conditions and AFAICT this bug is fixed with this patch. The X
> server patch that left a small window open that could cause weird events
> (though unlikely to crash) is in the server.
>
If you say so, let's merge it to the release to get a broader testing base.
So, the whole series is:
Acked-by: Ping Cheng <pingli...@gmail.com>
> Is it possible to make a common->enabled
> > so we can disable the Read in xf86Wacom.c or at least stop process the
> data
> > as what you did in this patch for all tools on the same port while
> > initializing the tools?
>
> With this patch, we don't need the common->enabled hack. If twools are on
> two different kernel devices, the bug can't hit us anyway, can it?
>
I hope so too. Let's wish for the best ;).
Ping
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