[libvirt] [PATCH] Don't crash in qemuBuildDeviceAddressStr

[Guido Günther]

qemuDomainAttachVirtioDiskDevice passes NULL as domainDef which is later
referenced in qemuDomainAttachVirtioDiskDevice:

 Program terminated with signal 11, Segmentation fault.
 #0  qemuBuildDeviceAddressStr (buf=buf at entry=0xb646de78, info=info at entry=0xb0a02360, qemuCaps=qemuCaps at entry=0xb8fdfdc8,
     domainDef=<error reading variable: Unhandled dwarf expression opcode 0xfa>,
     domainDef=<error reading variable: Unhandled dwarf expression opcode 0xfa>) at qemu/qemu_command.c:2869
 2869            for (i = 0; i < domainDef->ncontrollers; i++) {
 (gdb) bt
 #0  qemuBuildDeviceAddressStr (buf=buf at entry=0xb646de78, info=info at entry=0xb0a02360, qemuCaps=qemuCaps at entry=0xb8fdfdc8,
     domainDef=<error reading variable: Unhandled dwarf expression opcode 0xfa>,
     domainDef=<error reading variable: Unhandled dwarf expression opcode 0xfa>) at qemu/qemu_command.c:2869
 #1  0xb18ad6f8 in qemuBuildDriveDevStr (def=def at entry=0x0, disk=disk at entry=0xb0a02288, bootindex=bootindex at entry=0, qemuCaps=0xb8fdfdc8)
     at qemu/qemu_command.c:4316
 #2  0xb18d097f in qemuDomainAttachVirtioDiskDevice (conn=conn at entry=0xb90129a8, driver=driver at entry=0xb8fe29b8, vm=vm at entry=0xb8fe0c40,
     disk=disk at entry=0xb0a02288) at qemu/qemu_hotplug.c:278
 #3  0xb193f7ba in qemuDomainAttachDeviceDiskLive (dev=0xb0a35308, vm=0xb8fe0c40, driver=0xb8fe29b8, conn=0xb90129a8) at qemu/qemu_driver.c:6356
 #4  qemuDomainAttachDeviceLive (dev=0xb0a35308, vm=0xb8fe0c40, dom=<optimized out>) at qemu/qemu_driver.c:6418
 #5  qemuDomainAttachDeviceFlags (dom=dom at entry=0xb0a020b8,
     xml=xml at entry=0xb90953f0 "<disk type='file' device='disk'>\n  <source file='/var/lib/jenkins/jobs/libvirt-tck-build/workspace/scratchdir/200-disk-hotplug/extra.img'/>\n  <target dev='vdb' bus='virtio'/>\n</disk>\n", flags=3103664568, flags at entry=1) at qemu/qemu_driver.c:7079
 #6  0xb193f9cb in qemuDomainAttachDevice (dom=0xb0a020b8,
     xml=0xb90953f0 "<disk type='file' device='disk'>\n  <source file='/var/lib/jenkins/jobs/libvirt-tck-build/workspace/scratchdir/200-disk-hotplug/extra.img'/>\n  <target dev='vdb' bus='virtio'/>\n</disk>\n") at qemu/qemu_driver.c:7120
 #7  0xb7244827 in virDomainAttachDevice (domain=domain at entry=0xb0a020b8,
     xml=0xb90953f0 "<disk type='file' device='disk'>\n  <source file='/var/lib/jenkins/jobs/libvirt-tck-build/workspace/scratchdir/200-disk-hotplug/extra.img'/>\n  <target dev='vdb' bus='virtio'/>\n</disk>\n") at libvirt.c:10912
 #8  0xb7765ddb in remoteDispatchDomainAttachDevice (args=0xb9094ef0, rerr=0xb646e1f0, client=<optimized out>, server=<optimized out>,
     msg=<optimized out>) at remote_dispatch.h:2296
 #9  remoteDispatchDomainAttachDeviceHelper (server=0xb8fba0e8, client=0xb0a00730, msg=0xb0a350b8, rerr=0xb646e1f0, args=0xb9094ef0, ret=0xb9094dc8)
     at remote_dispatch.h:2274
 #10 0xb72b1013 in virNetServerProgramDispatchCall (msg=0xb0a350b8, client=0xb0a00730, server=0xb8fba0e8, prog=0xb8fc21c8)
     at rpc/virnetserverprogram.c:435
 #11 virNetServerProgramDispatch (prog=0xb8fc21c8, server=server at entry=0xb8fba0e8, client=0xb0a00730, msg=0xb0a350b8) at rpc/virnetserverprogram.c:305
 #12 0xb72aa167 in virNetServerProcessMsg (msg=<optimized out>, prog=<optimized out>, client=<optimized out>, srv=0xb8fba0e8)
     at rpc/virnetserver.c:165
 #13 virNetServerHandleJob (jobOpaque=0xb0a0a850, opaque=0xb8fba0e8) at rpc/virnetserver.c:186
 #14 0xb7189108 in virThreadPoolWorker (opaque=opaque at entry=0xb8fa3250) at util/virthreadpool.c:144
 #15 0xb71885e5 in virThreadHelper (data=0xb8fa32a8) at util/virthreadpthread.c:161
 #16 0xb70d6954 in start_thread (arg=0xb646eb70) at pthread_create.c:304
 #17 0xb704e95e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

This was found by libvirtt-tck:

     http://honk.sigxcpu.org:8001/job/libvirt-tck-debian-wheezy-qemu-session/1311/console

---
The problem was introduced somewhere around
4bc331c8945152d8942a23383c3eb92da1bc4194 but I didn't get around to
track this earlier.

Cheers,
 -- Guido
---
 src/qemu/qemu_hotplug.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index c9748d9..85d2ca9 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -275,7 +275,7 @@ int qemuDomainAttachVirtioDiskDevice(virConnectPtr conn,
         if (!(drivestr = qemuBuildDriveStr(conn, disk, false, priv->qemuCaps)))
             goto error;
 
-        if (!(devstr = qemuBuildDriveDevStr(NULL, disk, 0, priv->qemuCaps)))
+        if (!(devstr = qemuBuildDriveDevStr(vm->def, disk, 0, priv->qemuCaps)))
             goto error;
     }
 
@@ -616,7 +616,7 @@ int qemuDomainAttachUsbMassstorageDevice(virConnectPtr conn,
             goto error;
         if (!(drivestr = qemuBuildDriveStr(conn, disk, false, priv->qemuCaps)))
             goto error;
-        if (!(devstr = qemuBuildDriveDevStr(NULL, disk, 0, priv->qemuCaps)))
+        if (!(devstr = qemuBuildDriveDevStr(vm->def, disk, 0, priv->qemuCaps)))
             goto error;
     }
 
-- 
1.8.4.rc1