From: Igor Mammedov Date: Fri, 30 Dec 2016 14:33:11 +0000 (+0100) Subject: pc: fix crash in rtc_set_memory() if initial cpu is marked as hotplugged X-Git-Tag: qemu-xen-4.9.0-rc1~4 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=e88462aaa2f19e1238e77c1bcebbab7ef5380d7a;p=qemu-xen.git pc: fix crash in rtc_set_memory() if initial cpu is marked as hotplugged '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 or -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 Reviewed-by: Eduardo Habkost Signed-off-by: Igor Mammedov Message-Id: <1483108391-199542-1-git-send-email-imammedo@redhat.com> Signed-off-by: Paolo Bonzini --- diff --git a/hw/i386/pc.c b/hw/i386/pc.c index a9e64a88e5..02cc5a24f1 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 */ pcms->boot_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); }