[drm] [radeon] [3.1.4] slub memory corruption in drm_vblank_cleanup

[Jerome Glisse]

On Wed, Dec 14, 2011 at 08:00:04AM +0100, batouzo wrote:
> On 12/14/2011 12:47 AM, Jerome Glisse wrote:
> > On Tue, Dec 13, 2011 at 6:46 PM, Jerome Glisse <j.glisse at gmail.com> wrote:
> >> On Tue, Dec 13, 2011 at 6:33 PM, batouzo <batouzo at gmx.com> wrote:
> >>> On 12/14/2011 12:31 AM, Jerome Glisse wrote:
> >>>
> >>>>> Allocated in drm_vblank_init+0x139/0x260 [drm] + Freed in
> >>>>> drm_vblank_cleanup+0x78/0x90 [drm]
> >>>>> Allocated in drm_vblank_init+0xbe/0x260 [drm] + Freed in
> >>>>> drm_vblank_cleanup+0x48/0x90 [drm]
> >>>>>
> >>>>> It is Amd Bulldozer computer, with Radeon card:
> >>>>> 01:00.0 VGA compatible controller: ATI Technologies Inc Cedar PRO
> >>>>> [Radeon HD 5450]
> >>>>>
> >>>>>    messages: http://pastebin.com/NXN5EPtG
> >>>>> config used: http://pastebin.com/AeVxEX7c
> >>>
> >>>>
> >>>> Do you boot your kernel with kexec ? Does the patch help :
> >>>
> >>> Nope. Already seen that kexec bugfix on LKML but I start system normally
> >>> not with kexec.
> >>>
> >>>> http://people.freedesktop.org/~glisse/0001-drm-radeon-disable-possible-GPU-writeback-early-v3.patch
> >>>> If not please open bug on bugs.freedesktop.org against radeon driver.
> >>>
> >>> ok
> >>>
> >>
> >> Note that this patch might also help non kexec case.
> >>
> >> Cheers,
> >> Jerome
> > 
> > Oh and try booting with radeon.no_wb=1
> > 
> > Cheers,
> > Jerome
> 
> Using that patch on 3.1.4 results in locking for 60 seconds on startup,
> since it is now looking for firmware.
> 
> This wait was not present without that patch.
> 
> This looks familiar, like the 60 second wait when using netconsole
> caused by netconsole attempt to look for NIC card firmware too early
> (when / is not really mounted, just initramfs).
> 
> I will report soon does it fix the crash;
> 
> Though, the 60 second delay may influence the rarity of hitting BUG (it
> was the case with netconsole's 60sec wait).
> Should I just remove loading of this firmware?
> 

That patch doesn't change anything in regard of firmware. You need
firmware for GPU to be use otherwise kms is just a fancy framebuffer
driver.

Cheers,
Jerome