[Mesa-dev] [PATCH] i965: Check if unsynchronized map fails in BufferSubData.

[Kenneth Graunke]

This patch fixes a NULL pointer dereference in a test case which
allocates piles of buffers without ever freeing them, and repeatedly
tries to upload/fetch data to/from those buffers, without doing any
other work (such as rendering).

The same problem exists in a variety of other places, some of which are
more difficult to recover from.  This patch does not try to fix any of
those.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82683
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/intel_buffer_objects.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/intel_buffer_objects.c b/src/mesa/drivers/dri/i965/intel_buffer_objects.c
index 96dacde..d063d92 100644
--- a/src/mesa/drivers/dri/i965/intel_buffer_objects.c
+++ b/src/mesa/drivers/dri/i965/intel_buffer_objects.c
@@ -252,7 +252,10 @@ intel_bufferobj_subdata(struct gl_context * ctx,
    if (brw->has_llc) {
       if (offset + size <= intel_obj->gpu_active_start ||
           intel_obj->gpu_active_end <= offset) {
-         drm_intel_gem_bo_map_unsynchronized(intel_obj->buffer);
+         if (drm_intel_gem_bo_map_unsynchronized(intel_obj->buffer) < 0) {
+            _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBufferSubData (map failed)");
+            return;
+         }
          memcpy(intel_obj->buffer->virtual + offset, data, size);
          drm_intel_bo_unmap(intel_obj->buffer);
 
-- 
2.1.0