diff options
authorBrian Paul <>2017-06-19 12:22:09 -0600
committerAndres Gomez <>2017-06-28 20:15:05 +0300
commitccf9de7a59cd709e05800f433d1820705a7a5959 (patch)
parent4c2da8e40dee65e377b29a1d212b096235c6be47 (diff)
gallium/vbuf: avoid segfault when we get invalid glDrawRangeElements()
A common user error is to call glDrawRangeElements() with the 'end' argument being one too large. If we use the vbuf module to translate some vertex attributes this error can cause us to read past the end of the mapped hardware buffer, resulting in a crash. This patch adjusts the vertex count to avoid that issue. Typically, the vertex_count gets decremented by one. This fixes crashes with the Unigine Tropics and Sanctuary demos with older VMware hardware versions. The issue isn't hit with VGPU10 because we don't hit this fallback. No piglit changes. CC: Reviewed-by: Marek Olšák <> (cherry picked from commit d8148ed10ae5faea6f88f2f964797f4b0590c083) [Andres Gomez: pipe_vertex_buffer hadn't shrunk yet] Signed-off-by: Andres Gomez <> Conflicts: src/gallium/auxiliary/util/u_vbuf.c
1 files changed, 15 insertions, 1 deletions
diff --git a/src/gallium/auxiliary/util/u_vbuf.c b/src/gallium/auxiliary/util/u_vbuf.c
index f040f4a882d..7d4a44b19d7 100644
--- a/src/gallium/auxiliary/util/u_vbuf.c
+++ b/src/gallium/auxiliary/util/u_vbuf.c
@@ -423,8 +423,22 @@ u_vbuf_translate_buffers(struct u_vbuf *mgr, struct translate_key *key,
unsigned size = vb->stride ? num_vertices * vb->stride
: sizeof(double)*4;
- if (offset+size > vb->buffer->width0) {
+ if (offset + size > vb->buffer->width0) {
+ /* Don't try to map past end of buffer. This often happens when
+ * we're translating an attribute that's at offset > 0 from the
+ * start of the vertex. If we'd subtract attrib's offset from
+ * the size, this probably wouldn't happen.
+ */
size = vb->buffer->width0 - offset;
+ /* Also adjust num_vertices. A common user error is to call
+ * glDrawRangeElements() with incorrect 'end' argument. The 'end
+ * value should be the max index value, but people often
+ * accidentally add one to this value. This adjustment avoids
+ * crashing (by reading past the end of a hardware buffer mapping)
+ * when people do that.
+ */
+ num_vertices = (size + vb->stride - 1) / vb->stride;
map = pipe_buffer_map_range(mgr->pipe, vb->buffer, offset, size,