[Qemu-devel] [PATCH] qemu-img: initialize MapEntry object

[John Snow <jsnow@redhat.com>]

Commit 16b0d555 introduced an issue where we are not initializing
has_filename for the 'next' MapEntry object, which leads to interesting
errors in Valgrind and Clang -fsanitize=undefined both.

Zero the stack object at allocation AND make sure the utility to
populate the fields properly marks has_filename as false if applicable.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 qemu-img.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/qemu-img.c b/qemu-img.c
index f121980..5a85178 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2231,6 +2231,9 @@ static int get_block_status(BlockDriverState *bs, int64_t sector_num,
     if (file && e->has_offset) {
         e->has_filename = true;
         e->filename = file->filename;
+    } else {
+        e->has_filename = false;
+        e->filename = NULL;
     }
     return 0;
 }
@@ -2264,7 +2267,7 @@ static int img_map(int argc, char **argv)
     BlockDriverState *bs;
     const char *filename, *fmt, *output;
     int64_t length;
-    MapEntry curr = { .length = 0 }, next;
+    MapEntry curr = { .length = 0 }, next = { .length = 0 };
     int ret = 0;
 
     fmt = NULL;
-- 
2.4.3