memory_device_get_free_addr() dereferences @errp when
memory_device_check_addable() fails.  That's wrong; see the big
comment in error.h.  Introduced in commit 1b6d6af21b "pc-dimm: factor
out capacity and slot checks into MemoryDevice".

No caller actually passes null.

Fix anyway: splice in a local Error *err, and error_propagate().

Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-Id: <20191204093625.14836-11-armbru@redhat.com>
---
 hw/mem/memory-device.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c
index aef148c1d7..4bc9cf0917 100644
--- a/hw/mem/memory-device.c
+++ b/hw/mem/memory-device.c
@@ -99,6 +99,7 @@ static uint64_t memory_device_get_free_addr(MachineState *ms,
                                             uint64_t align, uint64_t size,
                                             Error **errp)
 {
+    Error *err = NULL;
     GSList *list = NULL, *item;
     Range as, new = range_empty;
 
@@ -123,8 +124,9 @@ static uint64_t memory_device_get_free_addr(MachineState *ms,
         return 0;
     }
 
-    memory_device_check_addable(ms, size, errp);
-    if (*errp) {
+    memory_device_check_addable(ms, size, &err);
+    if (err) {
+        error_propagate(errp, err);
         return 0;
     }
 
-- 
2.21.0