Re: [PATCH] drm/i915: disable KASAN for handlers

[Zhenyu Wang]

On 2017.03.30 11:46:27 +0200, Jiri Slaby wrote:
> Handlers are currently the only blocker to compile the kernel with gcc 7
> and KASAN+use-after-scope enabled:
> drivers/gpu/drm/i915/gvt/handlers.c:2200:1: error: the frame size of 43760 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
> drivers/gpu/drm/i915/gvt/handlers.c:2402:1: error: the frame size of 9400 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
> drivers/gpu/drm/i915/gvt/handlers.c:2628:1: error: the frame size of 11256 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
> 
> It is due to many expansions of MMIO_* macros in init_generic_mmio_info.
> INTEL_GVT_MMIO_OFFSET generates for each such line a __reg and an
> offset. There are too many for KASAN to keep up.
> 
> So disable KASAN for this file.
> 
> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
> Cc: Martin Liska <mliska@xxxxxxx>
> Cc: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx>
> Cc: Zhi Wang <zhi.a.wang@xxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxx>
> Cc: intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx
> Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> ---
>  drivers/gpu/drm/i915/gvt/Makefile | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/Makefile b/drivers/gpu/drm/i915/gvt/Makefile
> index b123c20e2097..942f1849d194 100644
> --- a/drivers/gpu/drm/i915/gvt/Makefile
> +++ b/drivers/gpu/drm/i915/gvt/Makefile
> @@ -6,3 +6,5 @@ GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
>  ccflags-y				+= -I$(src) -I$(src)/$(GVT_DIR) -Wall
>  i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))
>  obj-$(CONFIG_DRM_I915_GVT_KVMGT)	+= $(GVT_DIR)/kvmgt.o
> +
> +KASAN_SANITIZE_handlers.o := n
> -- 
> 2.12.2
> 

Applied this, we'd better cleanup legacy usage to current i915 mmio reg define. Thanks!

-- 
Open Source Technology Center, Intel ltd.

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