hsa/radeon: Clear allocated page to UNSIGNALED_EVENT_SLOT

Signed-off-by: Andrew Lewycky <Andrew.Lewycky@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>

drivers/gpu/hsa/radeon/kfd_events.c

@@ -140,7 +140,7 @@ bool allocate_signal_page(struct file *devkfd, struct kfd_process *p)
 	if (!backing_store)
 		goto fail_alloc_signal_store;
 
-	memset(backing_store, 0, PAGE_SIZE); /* prevent user-mode info leaks */
+	memset(backing_store, (uint8_t)UNSIGNALED_EVENT_SLOT, PAGE_SIZE); /* prevent user-mode info leaks */
 	page->kernel_address = backing_store;
 
 	if (list_empty(&p->signal_event_pages))

drivers/gpu/hsa/radeon/kfd_events.h

@@ -36,6 +36,7 @@
 /* Written into kfd_signal_slot_t to indicate that the event is not signaled.
  * Since the event protocol may need to write the event ID into memory, this
  * must not be a valid event ID.
+ * For the sake of easy memset-ing, this must be a byte pattern.
  */
 #define UNSIGNALED_EVENT_SLOT ((uint64_t)-1)