Re: [regression drm/noveau] suspend to ram -> BOOM: exception RIP: drm_calc_vbltimestamp_from_scanoutpos+335

From: Peter Zijlstra
Date: Fri Jul 14 2017 - 11:51:01 EST

On Fri, Jul 14, 2017 at 03:36:08PM +0200, Mike Galbraith wrote:
> Ok, a network outage gave me time to go hunting.  Indeed it is a bad
> interaction with the tree DRM merged into.  All DRM did was to slip a
> WARN_ON_ONCE() that nouveau triggers into a kernel module where such
> things no longer warn, they blow the box out of the water.  I made a
> dinky testcase module (attached), and bisected to the real root....
> 19d436268dde95389c616bb3819da73f0a8b28a8 is the first bad commit
> commit 19d436268dde95389c616bb3819da73f0a8b28a8
> Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Date: Sat Feb 25 08:56:53 2017 +0100
> debug: Add _ONCE() logic to report_bug()

Urgh, is for some mysterious reason the __bug_table section of modules
ending up in RO memory?

I forever get lost in that link magic :/