[PULL 05/14] vmdk: fix maybe uninitialized warnings

[Laurent Vivier]

From: Christian Borntraeger <borntraeger@de.ibm.com>

Fedora 32 gcc 10 seems to give false positives:

Compiling C object libblock.fa.p/block_vmdk.c.o
../block/vmdk.c: In function ‘vmdk_parse_extents’:
../block/vmdk.c:587:5: error: ‘extent’ may be used uninitialized in this 
function [-Werror=maybe-uninitialized]
  587 |     g_free(extent->l1_table);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~
../block/vmdk.c:754:17: note: ‘extent’ was declared here
  754 |     VmdkExtent *extent;
      |                 ^~~~~~
../block/vmdk.c:620:11: error: ‘extent’ may be used uninitialized in this 
function [-Werror=maybe-uninitialized]
  620 |     ret = vmdk_init_tables(bs, extent, errp);
      |           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../block/vmdk.c:598:17: note: ‘extent’ was declared here
  598 |     VmdkExtent *extent;
      |                 ^~~~~~
../block/vmdk.c:1178:39: error: ‘extent’ may be used uninitialized in this 
function [-Werror=maybe-uninitialized]
 1178 |             extent->flat_start_offset = flat_offset << 9;
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
../block/vmdk.c: In function ‘vmdk_open_vmdk4’:
../block/vmdk.c:581:22: error: ‘extent’ may be used uninitialized in this 
function [-Werror=maybe-uninitialized]
  581 |     extent->l2_cache =
      |     ~~~~~~~~~~~~~~~~~^
  582 |         g_malloc(extent->entry_size * extent->l2_size * L2_CACHE_SIZE);
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../block/vmdk.c:872:17: note: ‘extent’ was declared here
  872 |     VmdkExtent *extent;
      |                 ^~~~~~
../block/vmdk.c: In function ‘vmdk_open’:
../block/vmdk.c:620:11: error: ‘extent’ may be used uninitialized in this 
function [-Werror=maybe-uninitialized]
  620 |     ret = vmdk_init_tables(bs, extent, errp);
      |           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../block/vmdk.c:598:17: note: ‘extent’ was declared here
  598 |     VmdkExtent *extent;
      |                 ^~~~~~
cc1: all warnings being treated as errors
make: *** [Makefile.ninja:884: libblock.fa.p/block_vmdk.c.o] Error 1

fix them by assigning a default value.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Fam Zheng <fam@euphon.net>
Message-Id: <20200930155859.303148-2-borntraeger@de.ibm.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 block/vmdk.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index 8ec62c7ab798..a00dc00eb47a 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -595,7 +595,7 @@ static int vmdk_open_vmfs_sparse(BlockDriverState *bs,
     int ret;
     uint32_t magic;
     VMDK3Header header;
-    VmdkExtent *extent;
+    VmdkExtent *extent = NULL;
 
     ret = bdrv_pread(file, sizeof(magic), &header, sizeof(header));
     if (ret < 0) {
@@ -751,7 +751,7 @@ static int vmdk_open_se_sparse(BlockDriverState *bs,
     int ret;
     VMDKSESparseConstHeader const_header;
     VMDKSESparseVolatileHeader volatile_header;
-    VmdkExtent *extent;
+    VmdkExtent *extent = NULL;
 
     ret = bdrv_apply_auto_read_only(bs,
             "No write support for seSparse images available", errp);
@@ -869,7 +869,7 @@ static int vmdk_open_vmdk4(BlockDriverState *bs,
     uint32_t magic;
     uint32_t l1_size, l1_entry_sectors;
     VMDK4Header header;
-    VmdkExtent *extent;
+    VmdkExtent *extent = NULL;
     BDRVVmdkState *s = bs->opaque;
     int64_t l1_backup_offset = 0;
     bool compressed;
@@ -1088,7 +1088,7 @@ static int vmdk_parse_extents(const char *desc, 
BlockDriverState *bs,
     BdrvChild *extent_file;
     BdrvChildRole extent_role;
     BDRVVmdkState *s = bs->opaque;
-    VmdkExtent *extent;
+    VmdkExtent *extent = NULL;
     char extent_opt_prefix[32];
     Error *local_err = NULL;
 
-- 
2.26.2