[libvirt] 1.2.0 segfault on Centos 6

[Jiri Denemark]

On Tue, Feb 04, 2014 at 17:02:41 +0100, Franky Van Liedekerke wrote:
> Hi,
> 
> using libvirt 1.2.0 on a up-to-date Centos6.5 machine leads to 
> occasional segmentation faults (see below).
> Sometimes it runs for 5 minutes, sometimes for an hour, but after that 
> the result is always the same: segfault after some weird qom-list, that 
> apparently the qemu version on centos doesn't know. Has 1.2.1 a known 
> fix for this?

I believe the following patch should fix the crash. I'll do some testing
tomorrow and send it as a proper patch afterwards:

diff --git i/src/qemu/qemu_monitor.c w/src/qemu/qemu_monitor.c
index a968901..cdd817f 100644
--- i/src/qemu/qemu_monitor.c
+++ w/src/qemu/qemu_monitor.c
@@ -1019,7 +1019,9 @@ qemuMonitorFindBalloonObjectPath(qemuMonitorPtr mon,
                                  virDomainObjPtr vm,
                                  const char *curpath)
 {
-    size_t i, j, npaths = 0, nprops = 0;
+    size_t i, j;
+    int npaths = 0;
+    int nprops = 0;
     int ret = 0;
     char *nextpath = NULL;
     qemuMonitorJSONListPathPtr *paths = NULL;
@@ -1045,6 +1047,8 @@ qemuMonitorFindBalloonObjectPath(qemuMonitorPtr mon,
     VIR_DEBUG("Searching for Balloon Object Path starting at %s", curpath);
 
     npaths = qemuMonitorJSONGetObjectListPaths(mon, curpath, &paths);
+    if (npaths < 0)
+        return -1;
 
     for (i = 0; i < npaths && ret == 0; i++) {
 
@@ -1061,6 +1065,11 @@ qemuMonitorFindBalloonObjectPath(qemuMonitorPtr mon,
              * then this version of qemu/kvm does not support the feature.
              */
             nprops = qemuMonitorJSONGetObjectListPaths(mon, nextpath, &bprops);
+            if (nprops < 0) {
+                ret = -1;
+                goto cleanup;
+            }
+
             for (j = 0; j < nprops; j++) {
                 if (STREQ(bprops[j]->name, "guest-stats-polling-interval")) {
                     VIR_DEBUG("Found Balloon Object Path %s", nextpath);