This patch fixes a bug in which only enough memory for one cpumap is allocated for virDomainGetVcpus instead of one per virtual CPU. This Fixes an overflow. Additionally, it uses the return value of virDomainGetVcpus to determine how many cpuinfo structs were actually populated rather than assuming they all are. Finally, it uses the logical CPU number from the cpuinfo struct in the retrurn data instead of assuming CPU numbers are sequential. This should handle cases where arbitrary CPUs are offline. Signed-off-by: Charlie Smurthwaite <charlie(a)atechmedia.com&gt; --- ext/libvirt/domain.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/ext/libvirt/domain.c b/ext/libvirt/domain.c index d665907..c6de1bf 100644 --- a/ext/libvirt/domain.c +++ b/ext/libvirt/domain.c @@ -803,7 +803,7 @@ static VALUE libvirt_domain_vcpus(VALUE d) cpumaplen = VIR_CPU_MAPLEN(maxcpus); - cpumap = alloca(sizeof(unsigned char) * cpumaplen); + cpumap = alloca(sizeof(unsigned char) * cpumaplen * dominfo.nrVirtCpu); r = virDomainGetVcpus(ruby_libvirt_domain_get(d), cpuinfo, dominfo.nrVirtCpu, cpumap, cpumaplen); @@ -832,15 +832,16 @@ static VALUE libvirt_domain_vcpus(VALUE d) result = rb_ary_new(); - for (i = 0; i < dominfo.nrVirtCpu; i++) { + for (i = 0; i < r; i++) { vcpuinfo = rb_class_new_instance(0, NULL, c_domain_vcpuinfo); - rb_iv_set(vcpuinfo, "@number", UINT2NUM(i)); if (cpuinfo != NULL) { + rb_iv_set(vcpuinfo, "@number", INT2NUM(cpuinfo[i].number)); rb_iv_set(vcpuinfo, "@state", INT2NUM(cpuinfo[i].state)); rb_iv_set(vcpuinfo, "@cpu_time", ULL2NUM(cpuinfo[i].cpuTime)); rb_iv_set(vcpuinfo, "@cpu", INT2NUM(cpuinfo[i].cpu)); } else { + rb_iv_set(vcpuinfo, "@number", Qnil); rb_iv_set(vcpuinfo, "@state", Qnil); rb_iv_set(vcpuinfo, "@cpu_time", Qnil); rb_iv_set(vcpuinfo, "@cpu", Qnil); -- 2.25.0