Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: > On Wed, Mar 15, 2017 at 11:46:24AM +0200, Mika Kuoppala wrote: >> Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: >> >> > kasan is very good at detecting use-after-free. However, our requests >> > are allocated from a rcu-typesafe slab that is important for performance >> > but makes kasan less effective. When enabling kasan we are intentionally >> > looking for memory errors, disable the use of our caches to improve the >> > likelihood of kasan spotting a bug. >> > I didn't notice anything except the typo in the desc. Until someone makes a kmem_cache kasan aware, this patch would be useful if and when someone does kasan runs with our driver. The name could be DEBUG_KMEM_CACHE_DISABLE. It is more logical wrt to content of the patch. However perhaps the current name is more practical. Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> >> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> >> > --- >> > drivers/gpu/drm/i915/Kconfig.debug | 13 +++++++++++++ >> > drivers/gpu/drm/i915/i915_gem.c | 11 +++++++++-- >> > drivers/gpu/drm/i915/i915_gem_request.c | 25 ++++++++++++++++++++----- >> > drivers/gpu/drm/i915/i915_vma.c | 15 ++++++++++++--- >> > 4 files changed, 54 insertions(+), 10 deletions(-) >> > >> > diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug >> > index e091809a9a9e..bd8e90e4dfb9 100644 >> > --- a/drivers/gpu/drm/i915/Kconfig.debug >> > +++ b/drivers/gpu/drm/i915/Kconfig.debug >> > @@ -48,6 +48,19 @@ config DRM_I915_DEBUG_GEM >> > >> > If in doubt, say "N". >> > >> > +config DRM_I915_DEBUG_KASAN >> > + bool "Insert extra checks when using KASAN" >> > + default n >> > + depends on DRM_I915_WERROR >> > + depends on KASAN >> > + help >> > + Turns off use of kmem_caches to improve KASAN error detection, >> > + and inserts extra santiy checks. >> >> s/santiy/sanity. >> >> Would i915.kmem_cache=0/1 be too costly? > > More of the principle. Having module options means somebody will enable > it. Hiding it away underneath a bevy of expert config options makes it > much less likely. CI basically have to do two runs for each option -- if > we are using kasan, we want improved coverage, but we also need to test > that the default configuration works. It's probably best just to teach > kmem_cache itself to behave differently if it helps. I was just thinking > fine-grained swapping of behaviour would be benificial. > -Chris > > -- > Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
