[40/81] pc: fix crash in rtc_set_memory() if initial cpu is marked as hotplugged

Message ID 1490051325-3770-41-git-send-email-mdroth@linux.vnet.ibm.com
State New
Headers show

Commit Message

Michael Roth March 20, 2017, 11:08 p.m.
From: Igor Mammedov <imammedo@redhat.com>

'hotplugged' propperty is meant to be used on migration side when migrating
source with hotplugged devices.
However though it not exacly correct usage of 'hotplugged' property
it's possible to set generic hotplugged property for CPU using
 -cpu foo,hotplugged=on
 -global foo.hotplugged=on

in this case qemu crashes with following backtrace:


because pc_cpu_plug() assumes that hotplugged CPU could appear only after
rtc/fw_cfg are initialized.
Fix crash by replacing assumption with explicit checks of rtc/fw_cfg
and updating them only if they were initialized.

Cc: qemu-stable@nongnu.org
Reported-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <1483108391-199542-1-git-send-email-imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 26ef65beab852caf2b1ef4976e3473f2d525164d)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
 hw/i386/pc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)


diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index a9e64a8..02cc5a2 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1818,8 +1818,10 @@  static void pc_cpu_plug(HotplugHandler *hotplug_dev,
     /* increment the number of CPUs */
-    if (dev->hotplugged) {
+    if (pcms->rtc) {
         rtc_set_cpus_count(pcms->rtc, pcms->boot_cpus);
+    }
+    if (pcms->fw_cfg) {
         fw_cfg_modify_i16(pcms->fw_cfg, FW_CFG_NB_CPUS, pcms->boot_cpus);