[libvirt] [PATCHv3 20/19] blockjob: avoid null dereference on early error

Gcc with optimization warns: ../../src/qemu/qemu_driver.c: In function 'qemuDomainBlockCommit': ../../src/qemu/qemu_driver.c:12813:46: error: 'disk' may be used uninitialized in this function [-Werror=maybe-uninitialized] ../../src/qemu/qemu_driver.c:12698:25: note: 'disk' was declared here cc1: all warnings being treated as errors so obviously I had only been testing with optimization off. * src/qemu/qemu_driver.c (qemuDomainBlockCommit): Guard cleanup. --- Pushing under the build-breaker rule. src/qemu/qemu_driver.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 730c82b..feda4d9 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -12695,12 +12695,13 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base, char *device = NULL; int ret = -1; int idx; - virDomainDiskDefPtr disk; + virDomainDiskDefPtr disk = NULL; const char *top_canon = NULL; virStorageFileMetadataPtr top_meta = NULL; const char *top_parent = NULL; const char *base_canon = NULL; virCgroupPtr cgroup = NULL; + bool clean_access = false; virCheckFlags(VIR_DOMAIN_BLOCK_COMMIT_SHALLOW, -1); @@ -12790,6 +12791,7 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base, vm->def->name); goto endjob; } + clean_access = true; if (qemuDomainPrepareDiskChainElement(driver, vm, cgroup, disk, base_canon, VIR_DISK_CHAIN_READ_WRITE) < 0 || (top_parent && top_parent != disk->src && @@ -12805,7 +12807,7 @@ qemuDomainBlockCommit(virDomainPtr dom, const char *path, const char *base, qemuDomainObjExitMonitor(driver, vm); endjob: - if (ret < 0) { + if (ret < 0 && clean_access) { /* Revert access to read-only, if possible. */ qemuDomainPrepareDiskChainElement(driver, vm, cgroup, disk, base_canon, VIR_DISK_CHAIN_READ_ONLY); -- 1.7.11.7