From: Hamza Mahfooz hamza.mahfooz@amd.com
commit af22d6a869cc26b519bfdcd54293c53f2e491870 upstream.
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 sunpeng.li@amd.com Signed-off-by: Hamza Mahfooz hamza.mahfooz@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -4953,11 +4953,7 @@ static inline void fill_dc_dirty_rect(st int32_t y, int32_t width, int32_t 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; @@ -4973,7 +4969,6 @@ static inline void fill_dc_dirty_rect(st "[PLANE:%d] PSR SU dirty rect at (%d, %d) size (%d, %d)", plane->base.id, x, y, width, height);
-out: (*i)++; }
@@ -5055,6 +5050,9 @@ static void fill_dc_dirty_rects(struct d new_plane_state->plane->base.id, bb_changed, fb_changed, num_clips);
+ 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, @@ -5084,9 +5082,6 @@ static void fill_dc_dirty_rects(struct d new_plane_state->crtc_h, &i, false); }
- if (i > DC_MAX_DIRTY_RECTS) - goto ffu; - flip_addrs->dirty_rect_count = i; return;