[Beignet] [PATCH] Return error, don't crash, on allocation failure

[Rebecca N. Palmer]

As previously noted, when cl_mem_allocate fails, its error handling then 
calls cl_mem_delete on the incompletely-set-up buffer, which aborts at 
assert(mem->ctx).

This patch appears to fix the problem, but be warned I don't know this 
code well enough to know what else it might break.

Signed-off-by: Rebecca Palmer <rebecca_palmer at zoho.com>

diff --git a/src/cl_mem.c b/src/cl_mem.c
index 2ec89a4..99d8381 100644
--- a/src/cl_mem.c
+++ b/src/cl_mem.c
@@ -1071,16 +1071,19 @@ cl_mem_delete(cl_mem mem)
    }

    /* Remove it from the list */
-  assert(mem->ctx);
-  pthread_mutex_lock(&mem->ctx->buffer_lock);
-    if (mem->prev)
-      mem->prev->next = mem->next;
-    if (mem->next)
-      mem->next->prev = mem->prev;
-    if (mem->ctx->buffers == mem)
-      mem->ctx->buffers = mem->next;
-  pthread_mutex_unlock(&mem->ctx->buffer_lock);
-  cl_context_delete(mem->ctx);
+  if (mem->ctx) {
+    pthread_mutex_lock(&mem->ctx->buffer_lock);
+      if (mem->prev)
+        mem->prev->next = mem->next;
+      if (mem->next)
+        mem->next->prev = mem->prev;
+      if (mem->ctx->buffers == mem)
+        mem->ctx->buffers = mem->next;
+    pthread_mutex_unlock(&mem->ctx->buffer_lock);
+    cl_context_delete(mem->ctx);
+  } else {
+    assert((mem->prev == 0) && (mem->next == 0));
+  }

    /* Someone still mapped, unmap */
    if(mem->map_ref > 0) {