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Helpful to guarantee >>> we don't have stack garbage left in there for on-stack modes. >>> >>> Signed-off-by: Ville Syrjälä >>> --- >>> drivers/gpu/drm/drm_modes.c | 17 +++++++++++++++++ >>> include/drm/drm_modes.h | 2 ++ >>> 2 files changed, 19 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c >>> index 96b13e36293c..40d4ce4a1da4 100644 >>> --- a/drivers/gpu/drm/drm_modes.c >>> +++ b/drivers/gpu/drm/drm_modes.c >>> @@ -892,6 +892,23 @@ void drm_mode_copy(struct drm_display_mode *dst, const struct drm_display_mode * >>> } >>> EXPORT_SYMBOL(drm_mode_copy); >>> >>> +/** >>> + * drm_mode_init - initialize the mode from another mode >>> + * @dst: mode to overwrite >>> + * @src: mode to copy >>> + * >>> + * Copy an existing mode into another mode, zeroing the >>> + * list head of the destination mode. Typically used >>> + * to guarantee the list head is not left with stack >>> + * garbage in on-stack modes. >>> + */ >>> +void drm_mode_init(struct drm_display_mode *dst, const struct drm_display_mode *src) >>> +{ >>> + memset(dst, 0, sizeof(*dst)); >> Why not just clear the list head? Or maybe poison it? It would be more >> cleaner. > Then we have two places that need to be updated if some other field > gets introduced that needs preserving. With a full memset() we only > have to care about drm_mode_copy(). Don't see much point in > micro-optimizing this thing. > In such case DOC should be modified to avoid updating it "if some other field..." :) Anyway: Reviewed-by: Andrzej Hajda Regards Andrzej