[Nouveau] [REGRESSION] nouveau: Crash in gk104_fifo_intr_runlist()

[Eric Biggers]

Hi,

I think I've done about 10 reboots with the commit reverted and I never
experienced the crash.  But with 4.2.0-rc6 I get the crash on about every
other reboot.

Probably relevant: the computer on which the crash occurs has two GPUs (one
Intel and one Nvidia).  The Intel one is actually being used, whereas I
presume the Nvidia one is being automatically disabled shortly after boot,
perhaps when the crash occurs...

Eric

On Mon, Aug 10, 2015 at 11:28 PM, Alexandre Courbot <gnurou at gmail.com>
wrote:

> Indeed, and I am actually surprised to see one here. I will
> double-check that patch.
>
> Eric, would you be able to give an estimate of the repro rate for this
> issue? More testing with and without the patch would be welcome, it'd
> be good to know whether it is actually the culprit or not.
>
> On Mon, Aug 10, 2015 at 2:28 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> > Alexandre, could you take a look? 0xbad* generally comes from bad mmio
> > reads.
> >
> > On Aug 9, 2015 1:08 PM, "Eric Biggers" <ebiggers3 at gmail.com> wrote:
> >>
> >> Hi,
> >>
> >> I am testing Linux v4.2-rc5 and I am sporadically getting crashes
> shortly
> >> after
> >> startup in gk104_fifo_intr_runlist().  What I've found is that the
> 'mask'
> >> value
> >> read from offset 0x2a00 comes back as '0xbad0da00'.  This causes the
> >> 'engn'
> >> variable to be assigned the value 9, which is invalid; then wake_up() is
> >> called
> >> on an uninitialized waitqueue which causes the crash.
> >>
> >> Reverting commit 1addc12648521d ("drm/nouveau/fifo/gk104: kick channels
> >> when
> >> deactivating them") seemed to make the problem go away, although I can't
> >> be 100%
> >> sure because the problem is sporadic.
> >>
> >> Attached an example of the kernel log up to the crash.
> >>
> >> Eric
> >>
> >> _______________________________________________
> >> Nouveau mailing list
> >> Nouveau at lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/nouveau
> >>
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/nouveau/attachments/20150811/d80bf893/attachment.html>