Fix "prefer downloaded" dive sample merging case

When we have a preferred dive computer that overrides old information
when merging two dives, we just copy the dive computer data over.
However, we need to clear the source of the dive computer data so that
we then don't free the sample data when that old source of the newly
merged dive gets free'd.

This fixes a memory scribble (and likely SIGSEGV) for the "prefer
downloaded" case.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/dive.c b/dive.c
index 698bd00e9..d69aee355 100644
--- a/dive.c
+++ b/dive.c
@@ -1103,6 +1103,13 @@ struct dive *merge_dives(struct dive *a, struct dive *b, int offset, gboolean pr
 	merge_equipment(res, a, b);
 	if (dl) {
 		res->dc = dl->dc;
+		/*
+		 * Since we copied the events and samples,
+		 * we can't free them from the source when
+		 * we free it - so make sure the source
+		 * dive computer data is cleared out.
+		 */
+		memset(&dl->dc, 0, sizeof(dl->dc));
 	} else {
 		merge_events(&res->dc, &a->dc, &b->dc, offset);
 		merge_samples(&res->dc, &a->dc, &b->dc, offset);