Messages in this thread | | | Date | Thu, 3 Nov 2022 15:28:43 +0100 | Subject | Re: [PATCH] drm/mediatek: Fix return type of mtk_hdmi_bridge_mode_valid() | From | AngeloGioacchino Del Regno <> |
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Il 02/11/22 16:47, Nathan Chancellor ha scritto: > With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), > indirect call targets are validated against the expected function > pointer prototype to make sure the call target is valid to help mitigate > ROP attacks. If they are not identical, there is a failure at run time, > which manifests as either a kernel panic or thread getting killed. A > proposed warning in clang aims to catch these at compile time, which > reveals: > > drivers/gpu/drm/mediatek/mtk_hdmi.c:1407:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_bridge *, const struct drm_display_info *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] > .mode_valid = mtk_hdmi_bridge_mode_valid, > ^~~~~~~~~~~~~~~~~~~~~~~~~~ > 1 error generated. > > ->mode_valid() in 'struct drm_bridge_funcs' expects a return type of > 'enum drm_mode_status', not 'int'. Adjust the return type of > mtk_hdmi_bridge_mode_valid() to match the prototype's to resolve the > warning and CFI failure. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1750 > Reported-by: Sami Tolvanen <samitolvanen@google.com> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
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