monitor: Catch printing to non-existent monitor
The monitor_vprintf() function now touches the 'mon' pointer
before calling monitor_puts(), this causes block migration
to segfault as its functions call monitor_printf() with a
NULL 'mon'.
To fix the problem this commit moves the 'mon' NULL check
from monitor_puts() to monitor_vprintf().
This can potentially hide bugs, but for some reason this has
been the behavior for a long time.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/monitor.c b/monitor.c
index b518cc4..ebd0282 100644
--- a/monitor.c
+++ b/monitor.c
@@ -177,9 +177,6 @@
{
char c;
- if (!mon)
- return;
-
for(;;) {
c = *str++;
if (c == '\0')
@@ -195,6 +192,9 @@
void monitor_vprintf(Monitor *mon, const char *fmt, va_list ap)
{
+ if (!mon)
+ return;
+
if (mon->mc && !mon->mc->print_enabled) {
qemu_error_new(QERR_UNDEFINED_ERROR);
} else {
