Re: Linux 6.12.4 - crash dma_alloc_attrs+0x12b via ipu6

[Greg Kroah-Hartman]

On Tue, Dec 10, 2024 at 02:24:56PM +0200, Jani Nikula wrote:
> On Tue, 10 Dec 2024, Genes Lists <lists@xxxxxxxxxxxx> wrote:
> > On Tue, 2024-12-10 at 10:58 +0200, Jani Nikula wrote:
> >> On Tue, 10 Dec 2024, Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> >> wrote:
> >> > Hi,
> >> > 
> >> > > ...
> >> > > FYI 6.12.4 got a crash shortly after booting in dma_alloc_attrs -
> >> > > maybe
> >> > > triggered in ipu6_probe. Crash only happened on laptop with ipu6.
> >> > > All
> >> > > other machines are running fine.
> >> > 
> >> > Have you read the dmesg further than the IPU6 related warning? The
> >> > IPU6
> >> > driver won't work (maybe not even probe?) but if the system
> >> > crashes, it
> >> > appears unlikely the IPU6 drivers would have something to do with
> >> > that.
> >> > Look for warnings on linked list corruption later, they seem to be
> >> > coming
> >> > from the i915 driver.
> >> 
> >> And the list corruption is actually happening in
> >> cpu_latency_qos_update_request(). I don't see any i915 changes in
> >> 6.12.4
> >> that could cause it.
> >> 
> >> I guess the question is, when did it work? Did 6.12.3 work?
> >> 
> >> 
> >> BR,
> >> Jani.
> >
> >
> >  - 6.12.1 worked
> >
> >  - mainline - works (but only with i915 patch set [1] otherwise there
> > are no graphics at all)
> >
> >     [1] https://patchwork.freedesktop.org/series/141911/
> >
> > - 6.12.3 - crashed (i see i915 not ipu6) and again it has       
> >     cpu_latency_qos_update_request+0x61/0xc0
> 
> Thanks for testing.
> 
> There are no changes to either i915 or kernel/power between 6.12.1 and
> 6.12.4.
> 
> There are some changes to drm core, but none that could explain this.
> 
> Maybe try the same kernels a few more times to see if it's really
> deterministic? Not that I have obvious ideas where to go from there, but
> it's a clue nonetheless.

'git bisect' would be nice to run if possible...