On 07/16/13 08:31, Alex Jia wrote:
If users haven't configured guest agent then qemuAgentCommand() will
dereference a NULL 'mon' pointer, which causes crash of libvirtd.
uhh, right :/ I broke that :/
GDB backtrace:
(gdb) bt
#0 virNetServerFatalSignal (sig=11, siginfo=<value optimized out>, context=<value optimized out>) at rpc/virnetserver.c:326
#1 <signal handler called>
#2 qemuAgentCommand (mon=0x0, cmd=0x7f39300017b0, reply=0x7f394b090910, seconds=-2) at qemu/qemu_agent.c:975
#3 0x00007f39429507f6 in qemuAgentGetVCPUs (mon=0x0, info=0x7f394b0909b8) at qemu/qemu_agent.c:1475
#4 0x00007f39429d9857 in qemuDomainGetVcpusFlags (dom=<value optimized out>, flags=9) at qemu/qemu_driver.c:4849
#5 0x00007f3957dffd8d in virDomainGetVcpusFlags (domain=0x7f39300009c0, flags=8) at libvirt.c:9843
How to reproduce?
# To start a guest without guest agent configuration
# then run the following cmdline
# virsh vcpucount foobar --guest
error: End of file while reading data: Input/output error
error: One or more references were leaked after disconnect from the hypervisor
error: Failed to reconnect to the hypervisor
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=984821
Signed-off-by: Alex Jia <ajia@xxxxxxxxxx>
---
src/qemu/qemu_driver.c | 12 ++++++++++++
1 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 495867a..1448aa7 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -4122,6 +4122,12 @@ qemuDomainSetVcpusFlags(virDomainPtr dom, unsigned int nvcpus,
goto endjob;
}
+ if (!priv->agent) {
+ virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
+ _("QEMU guest agent is not configured"));
+ goto cleanup;
+ }
+
We probably also want:
if (priv->agentError) {
virReportError(VIR_ERR_AGENT_UNRESPONSIVE, "%s",
_("QEMU guest agent is not "
"available due to an error"));
goto cleanup;
}
if (!priv->agent) {
virReportError(VIR_ERR_ARGUMENT_UNSUPPORTED, "%s",
_("QEMU guest agent is not configured"));
goto cleanup;
}
qemuDomainObjEnterAgent(vm);
ncpuinfo = qemuAgentGetVCPUs(priv->agent, &cpuinfo);
qemuDomainObjExitAgent(vm);
Peter
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