Re: [PATCH v2] Add VM info to improve error log message for qemu monitor

This patch is to determine the VM which had IO or socket hangup error. Accessing directly vm->def->name inside qemuMonitorIO() or qemuMonitorSend() might leads to illegal access as we are out of 'vm' context and vm->def might not exist. Adding a field "domainName" inside mon object to access vm name and initialising it when creating mon object.

Signed-off-by: Rohit Kumar <rohit.kumar3(a)nutanix.com&gt; --- diff to v1: - Adding a field domainName inside _qemuMonitor struct for accessing vm name instead of directly accessing mon->vm->def->name. - Link to v1: https://listman.redhat.com/archives/libvir-list/2021-December/msg00217.html - Talked with peter on RFC and he suggested me to add a field inside monitor struct to get VM name. src/qemu/qemu_monitor.c | 47 +++++++++++++++++++++++++---------------- 1 file changed, 29 insertions(+), 18 deletions(-) diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c index dda6ae9796..c3a0227795 100644 --- a/src/qemu/qemu_monitor.c +++ b/src/qemu/qemu_monitor.c @@ -80,6 +80,7 @@ struct _qemuMonitor { GSource *watch; virDomainObj *vm; + char *domainName;

qemuMonitorCallbacks *cb; void *callbackOpaque; @@ -243,6 +244,7 @@ qemuMonitorDispose(void *obj) virCondDestroy(&mon->notify); g_free(mon->buffer); g_free(mon->balloonpath); + g_free(mon->domainName); } @@ -530,13 +532,18 @@ qemuMonitorIO(GSocket *socket G_GNUC_UNUSED, qemuMonitor *mon = opaque; bool error = false; bool hangup = false; + virDomainObj *vm = NULL; + char *vmName = NULL;

virObjectRef(mon); + vm = mon->vm; + vmName = mon->domainName;

+ /* lock access to the monitor and protect fd */ virObjectLock(mon); #if DEBUG_IO - VIR_DEBUG("Monitor %p I/O on socket %p cond %d", mon, socket, cond); + VIR_DEBUG("Monitor %p I/O on socket %p cond %d vm=%p name=%s", mon, socket, cond, vm, NULLSTR(vmName)); #endif if (mon->fd == -1 || !mon->watch) { virObjectUnlock(mon); @@ -583,8 +590,8 @@ qemuMonitorIO(GSocket *socket G_GNUC_UNUSED, if (!error && !mon->goteof && cond & G_IO_ERR) { - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("Invalid file descriptor while waiting for monitor")); + virReportError(VIR_ERR_INTERNAL_ERROR, + _("%s: Invalid file descriptor while waiting for monitor"), NULLSTR(vmName));

mon->goteof = true; } } @@ -609,13 +616,14 @@ qemuMonitorIO(GSocket *socket G_GNUC_UNUSED, virResetLastError(); } else { if (virGetLastErrorCode() == VIR_ERR_OK && !mon->goteof) - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("Error while processing monitor IO")); + virReportError(VIR_ERR_INTERNAL_ERROR, + _("%s: Error while processing monitor IO"), NULLSTR(vmName));

virCopyLastError(&mon->lastError); virResetLastError(); } - VIR_DEBUG("Error on monitor %s", NULLSTR(mon->lastError.message)); + VIR_DEBUG("Error on monitor %s mon=%p vm=%p name=%s", + NULLSTR(mon->lastError.message), mon, vm, NULLSTR(vmName)); /* If IO process resulted in an error & we have a message, * then wakeup that waiter */ if (mon->msg && !mon->msg->finished) { @@ -631,22 +639,22 @@ qemuMonitorIO(GSocket *socket G_GNUC_UNUSED, * will try to acquire the virDomainObj *mutex next */ if (mon->goteof) { qemuMonitorEofNotifyCallback eofNotify = mon->cb->eofNotify; - virDomainObj *vm = mon->vm; /* Make sure anyone waiting wakes up now */ virCondSignal(&mon->notify); virObjectUnlock(mon); - VIR_DEBUG("Triggering EOF callback"); + VIR_DEBUG("Triggering EOF callback mon=%p vm=%p name=%s", + mon, vm, NULLSTR(vmName)); (eofNotify)(mon, vm, mon->callbackOpaque); virObjectUnref(mon); } else if (error) { qemuMonitorErrorNotifyCallback errorNotify = mon->cb->errorNotify; - virDomainObj *vm = mon->vm; /* Make sure anyone waiting wakes up now */ virCondSignal(&mon->notify); virObjectUnlock(mon); - VIR_DEBUG("Triggering error callback"); + VIR_DEBUG("Triggering error callback mon=%p vm=%p name=%s", + mon, vm, NULLSTR(vmName)); (errorNotify)(mon, vm, mon->callbackOpaque); virObjectUnref(mon); } else { @@ -694,6 +702,7 @@ qemuMonitorOpenInternal(virDomainObj *vm, mon->fd = fd; mon->context = g_main_context_ref(context); mon->vm = virObjectRef(vm); + mon->domainName = g_strdup(vm->def->name);

mon->waitGreeting = true; mon->cb = cb; mon->callbackOpaque = opaque; @@ -932,17 +941,19 @@ qemuMonitorSend(qemuMonitor *mon, qemuMonitorMessage *msg) { int ret = -1; + virDomainObj *vm = mon->vm; + char *vmName = mon->domainName; /* Check whether qemu quit unexpectedly */ if (mon->lastError.code != VIR_ERR_OK) { - VIR_DEBUG("Attempt to send command while error is set %s", - NULLSTR(mon->lastError.message)); + VIR_DEBUG("Attempt to send command while error is set %s mon=%p vm=%p name=%s", + NULLSTR(mon->lastError.message), mon, vm, NULLSTR(vmName)); virSetError(&mon->lastError); return -1; } if (mon->goteof) { - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("End of file from qemu monitor")); + virReportError(VIR_ERR_INTERNAL_ERROR, + _("%s: End of file from qemu monitor"), NULLSTR(vmName));

return -1; } @@ -955,15 +966,15 @@ qemuMonitorSend(qemuMonitor *mon, while (!mon->msg->finished) { if (virCondWait(&mon->notify, &mon->parent.lock) < 0) { - virReportError(VIR_ERR_INTERNAL_ERROR, "%s", - _("Unable to wait on monitor condition")); + virReportError(VIR_ERR_INTERNAL_ERROR, + _("%s: Unable to wait on monitor condition"), NULLSTR(vmName));

goto cleanup; } } if (mon->lastError.code != VIR_ERR_OK) { - VIR_DEBUG("Send command resulted in error %s", - NULLSTR(mon->lastError.message)); + VIR_DEBUG("Send command resulted in error %s mon=%p vm=%p name=%s", + NULLSTR(mon->lastError.message), mon, vm, NULLSTR(vmName)); virSetError(&mon->lastError); goto cleanup; } -- 2.25.1