DRM-related kmalloc-32 memory leak in 2.6.35

[David Rientjes]

On Mon, 27 Sep 2010, Andrew Morton wrote:

> > Still present in 2.6.35. Appears to be DRM:
> > 
> >     845 drm_vm_open_locked+0x72/0x109 age=43/37572/59269 pid=2089
> > cpus=0-1
> > 
> > That's after about a minute of uptime. Grows to 100k in about a day.
> > 
> > dmesg bits:
> > [    0.834653] [drm] Initialized drm 1.1.0 20060810
> > [    0.834986] pci 0000:00:02.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
> > [    0.834995] pci 0000:00:02.0: setting latency timer to 64
> > [    1.002572] mtrr: type mismatch for e0000000,10000000 old: write-back new: write-combining
> > [    1.002580] [drm] MTRR allocation failed.  Graphics performance may suffer.
> > [    1.019880] acpi device:03: registered as cooling_device2
> > [    1.021520] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input3
> > [    1.021543] ACPI: Video Device [GFX0] (multi-head: yes  rom: no  post: no)
> > [    1.021855] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
> > 
> > This is with:
> > 
> > 00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960
> > Integrated Graphics Controller (rev 03)
> > 00:02.1 Display controller: Intel Corporation Mobile GM965/GL960
> > Integrated Graphics Controller (rev 03)
> > 
> 
> Matt tells me that this (drop-dead box-killing!) bug is still present
> in current kernels.  Could someone take a look please?
> 
> The code seems very simple, and I couldn't spot a problem.  Probably
> this means that I'm even simpler.
> 

I'm wondering what reading /sys/kernel/debug/dri/.../vma says when 
DRM_DEBUG_CODE is enabled, it seems to have been written for this type of 
debugging.