From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39466) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRks6-0008K3-J9 for qemu-devel@nongnu.org; Fri, 05 Feb 2016 13:12:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aRks5-00019f-Ee for qemu-devel@nongnu.org; Fri, 05 Feb 2016 13:12:42 -0500 From: John Snow Date: Fri, 5 Feb 2016 13:12:33 -0500 Message-Id: <1454695953-14710-1-git-send-email-jsnow@redhat.com> Subject: [Qemu-devel] [PATCH v2] qemu-img: initialize MapEntry object List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, John Snow , famz@redhat.com, qemu-devel@nongnu.org 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 --- v2: Initialize with a compound literal as a future-proofing measure. qemu-img.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index f121980..4617d3b 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -2195,6 +2195,7 @@ static int get_block_status(BlockDriverState *bs, int64_t sector_num, int64_t ret; int depth; BlockDriverState *file; + bool has_offset; /* As an optimization, we could cache the current range of unallocated * clusters in each file of the chain, and avoid querying the same @@ -2221,17 +2222,20 @@ static int get_block_status(BlockDriverState *bs, int64_t sector_num, depth++; } - e->start = sector_num * BDRV_SECTOR_SIZE; - e->length = nb_sectors * BDRV_SECTOR_SIZE; - e->data = !!(ret & BDRV_BLOCK_DATA); - e->zero = !!(ret & BDRV_BLOCK_ZERO); - e->offset = ret & BDRV_BLOCK_OFFSET_MASK; - e->has_offset = !!(ret & BDRV_BLOCK_OFFSET_VALID); - e->depth = depth; - if (file && e->has_offset) { - e->has_filename = true; - e->filename = file->filename; - } + has_offset = !!(ret & BDRV_BLOCK_OFFSET_VALID); + + *e = (MapEntry) { + .start = sector_num * BDRV_SECTOR_SIZE, + .length = nb_sectors * BDRV_SECTOR_SIZE, + .data = !!(ret & BDRV_BLOCK_DATA), + .zero = !!(ret & BDRV_BLOCK_ZERO), + .offset = ret & BDRV_BLOCK_OFFSET_MASK, + .has_offset = has_offset, + .depth = depth, + .has_filename = file && has_offset, + .filename = file && has_offset ? file->filename : NULL, + }; + return 0; } -- 2.4.3