[Tarantool-patches] [PATCH] vinyl: fix passing uninitialized parameter to vy_page_find_key()

[Nikita Pettik <korablev@tarantool.org>]

vy_page_find_key() assumes that equal_key parameter is initialized since
it is used unconditionally. There are several places where
vy_page_find_key() is called:

- vy_slice_stream_search() calls vy_page_find_key();
- vy_run_iterator_read() calls vy_run_iterator_load_page(),
which in turn calls vy_page_find_key();
- vy_run_iterator_search() also calls vy_run_iterator_load_page().

First two fixes are obvious - lifespan of parameter passed to
*_find_key() is clear and restricted by caller. In the last case
firstly vy_page_find_key() is called, but equal_key output value is not
used. Then it is re-assigned with task->equal_found which is the result
of another on vy_page_find_key() invocation in vy_page_read_cb. So it is
safe to initialize equal_found parameter with 'false' value as well.

Closes #5078
---
Branch: https://github.com/tarantool/tarantool/tree/np/gh-5078-uninit-var-sanitizer
Issue: https://github.com/tarantool/tarantool/issues/5078

 src/box/vy_run.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/box/vy_run.c b/src/box/vy_run.c
index 54cf028d0..db4565954 100644
--- a/src/box/vy_run.c
+++ b/src/box/vy_run.c
@@ -1095,7 +1095,7 @@ vy_run_iterator_read(struct vy_run_iterator *itr,
 		     struct vy_entry *ret)
 {
 	struct vy_page *page;
-	bool equal_found;
+	bool equal_found = false;
 	uint32_t pos_in_page;
 	int rc = vy_run_iterator_load_page(itr, pos.page_no, vy_entry_none(),
 					   ITER_GE, &page, &pos_in_page,
@@ -1129,7 +1129,7 @@ vy_run_iterator_search(struct vy_run_iterator *itr,
 					       equal_key);
 	if (pos->page_no == itr->slice->run->info.page_count)
 		return 1;
-	bool equal_in_page;
+	bool equal_in_page = false;
 	struct vy_page *page;
 	int rc = vy_run_iterator_load_page(itr, pos->page_no, key,
 					   iterator_type, &page,
@@ -2615,7 +2615,7 @@ vy_slice_stream_search(struct vy_stmt_stream *virt_stream)
 	if (vy_slice_stream_read_page(stream) != 0)
 		return -1;
 
-	bool unused;
+	bool unused = false;
 	stream->pos_in_page = vy_page_find_key(stream->page,
 					       stream->slice->begin,
 					       stream->cmp_def,
-- 
2.17.1