On 6/21/23 17:57, Hamza Mahfooz wrote:

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") Signed-off-by: Hamza Mahfooz hamza.mahfooz@amd.com

Reviewed-by: Leo Li sunpeng.li@amd.com

Thanks!

---

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 64b8dcf8dbda..66bb03d503ea 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -5065,11 +5065,7 @@ 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; @@ -5085,7 +5081,6 @@ 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)++; } @@ -5172,6 +5167,9 @@ 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,

@@ -5201,9 +5199,6 @@ 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;