kvm: fix memory leak on failure to read stats descriptors

Reported by Coverity as CID 1490142.  Since the size is constant and the
lifetime is the same as the StatsDescriptors struct, embed the struct
directly instead of using a separate allocation.

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 4 insertions, 5 deletions

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 7c8ce18bdd..5acab1767f 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -3908,7 +3908,7 @@ exit:
 typedef struct StatsDescriptors {
     const char *ident; /* cache key, currently the StatsTarget */
     struct kvm_stats_desc *kvm_stats_desc;
-    struct kvm_stats_header *kvm_stats_header;
+    struct kvm_stats_header kvm_stats_header;
     QTAILQ_ENTRY(StatsDescriptors) next;
 } StatsDescriptors;
 
@@ -3939,7 +3939,7 @@ static StatsDescriptors *find_stats_descriptors(StatsTarget target, int stats_fd
     descriptors = g_new0(StatsDescriptors, 1);
 
     /* Read stats header */
-    kvm_stats_header = g_malloc(sizeof(*kvm_stats_header));
+    kvm_stats_header = &descriptors->kvm_stats_header;
     ret = read(stats_fd, kvm_stats_header, sizeof(*kvm_stats_header));
     if (ret != sizeof(*kvm_stats_header)) {
         error_setg(errp, "KVM stats: failed to read stats header: "
@@ -3964,7 +3964,6 @@ static StatsDescriptors *find_stats_descriptors(StatsTarget target, int stats_fd
         g_free(kvm_stats_desc);
         return NULL;
     }
-    descriptors->kvm_stats_header = kvm_stats_header;
     descriptors->kvm_stats_desc = kvm_stats_desc;
     descriptors->ident = ident;
     QTAILQ_INSERT_TAIL(&stats_descriptors, descriptors, next);
@@ -3989,7 +3988,7 @@ static void query_stats(StatsResultList **result, StatsTarget target,
         return;
     }
 
-    kvm_stats_header = descriptors->kvm_stats_header;
+    kvm_stats_header = &descriptors->kvm_stats_header;
     kvm_stats_desc = descriptors->kvm_stats_desc;
     size_desc = sizeof(*kvm_stats_desc) + kvm_stats_header->name_size;
 
@@ -4054,7 +4053,7 @@ static void query_stats_schema(StatsSchemaList **result, StatsTarget target,
         return;
     }
 
-    kvm_stats_header = descriptors->kvm_stats_header;
+    kvm_stats_header = &descriptors->kvm_stats_header;
     kvm_stats_desc = descriptors->kvm_stats_desc;
     size_desc = sizeof(*kvm_stats_desc) + kvm_stats_header->name_size;