copy_to_user() returns the number of bytes remaining to be copied.  We
want to return -EFAULT here instead.  Also there seems like no point
in continuing the loop if copy_to_user() fails.

Fixes: 02b23803c6af ('staging: android: ion: Add ioctl to query available 
Signed-off-by: Dan Carpenter <>
The error handling still might be wrong here.  Do we really want to
change query->cnt?  Please review.

diff --git a/drivers/staging/android/ion/ion.c 
index 396ded5..4cec0b2 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -1187,8 +1187,10 @@ int ion_query_heaps(struct ion_client *client, struct 
ion_heap_query *query)
                hdata.type = heap->type;
                hdata.heap_id = heap->id;
-               ret = copy_to_user(&buffer[cnt],
-                                  &hdata, sizeof(hdata));
+               if (copy_to_user(&buffer[cnt], &hdata, sizeof(hdata))) {
+                       ret = -EFAULT;
+                       break;
+               }
                if (cnt >= max_cnt)
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