From af22d6a869cc26b519bfdcd54293c53f2e491870 Mon Sep 17 00:00:00 2001 From: Hamza Mahfooz Date: Wed, 21 Jun 2023 15:19:05 -0400 Subject: [PATCH] drm/amd/display: perform a bounds check before filling dirty rectangles Currently, it is possible for us to access memory that we shouldn't. Since, we acquire (possibly dangling) pointers to dirty rectangles before doing a bounds check to make sure we can actually accommodate the number of dirty rectangles userspace has requested to fill. This issue is especially evident if a compositor requests both MPO and damage clips at the same time, in which case I have observed a soft-hang. So, to avoid this issue, perform the bounds check before filling a single dirty rectangle and WARN() about it, if it is ever attempted in fill_dc_dirty_rect(). Cc: stable@vger.kernel.org # 6.1+ Fixes: 30ebe41582d1 ("drm/amd/display: add FB_DAMAGE_CLIPS support") Reviewed-by: Leo Li Signed-off-by: Hamza Mahfooz Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 514f6785a020..7fa0d0ec45c9 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -5063,11 +5063,7 @@ static inline void fill_dc_dirty_rect(struct drm_plane *plane, s32 y, s32 width, s32 height, int *i, bool ffu) { - if (*i > DC_MAX_DIRTY_RECTS) - return; - - if (*i == DC_MAX_DIRTY_RECTS) - goto out; + WARN_ON(*i >= DC_MAX_DIRTY_RECTS); dirty_rect->x = x; dirty_rect->y = y; @@ -5083,7 +5079,6 @@ static inline void fill_dc_dirty_rect(struct drm_plane *plane, "[PLANE:%d] PSR SU dirty rect at (%d, %d) size (%d, %d)", plane->base.id, x, y, width, height); -out: (*i)++; } @@ -5170,6 +5165,9 @@ static void fill_dc_dirty_rects(struct drm_plane *plane, *dirty_regions_changed = bb_changed; + if ((num_clips + (bb_changed ? 2 : 0)) > DC_MAX_DIRTY_RECTS) + goto ffu; + if (bb_changed) { fill_dc_dirty_rect(new_plane_state->plane, &dirty_rects[i], new_plane_state->crtc_x, @@ -5199,9 +5197,6 @@ static void fill_dc_dirty_rects(struct drm_plane *plane, new_plane_state->crtc_h, &i, false); } - if (i > DC_MAX_DIRTY_RECTS) - goto ffu; - flip_addrs->dirty_rect_count = i; return; -- 2.11.0