[Crash-utility] [PATCH] Account for the changed type of the domain.vcpu field in Xen4

[Petr Tesarik]

On Friday 07 of January 2011 16:27:55 Dave Anderson wrote:
> ----- Original Message -----
>
> > The 'vcpu' field changed from a fixed array to a pointer to an array. 
> > Change xen_hyper_store_domain_context to account for this change.
>
> Presuming this tests OK on older hypervisor dumps, this looks OK.
> Queued for the next release based upon testing.

Hi Dave,

older Xen hypervisors didn't have the "max_vcpus" field in struct domain, so 
there is in fact no change for them.

However, thinking about it some more, this might be affected by the increase 
of XEN_HYPER_MAX_VIRT_CPUS. Although I haven't seen a failure, let me check 
first whether a crash session on a dump from Xen 3.3 attempts to read past 
array boundaries.

Petr Tesarik
SUSE Linux

> Thanks,
>   Dave
>
> > Signed-off-by: Petr Tesarik <ptesarik at suse.cz>
> > ---
> > xen_hyper.c | 40 +++++++++++++++++++++++++++++++++++++---
> > xen_hyper_defs.h | 1 +
> > 2 files changed, 38 insertions(+), 3 deletions(-)
> >
> > --- a/xen_hyper.c
> > +++ b/xen_hyper.c
> > @@ -219,6 +219,7 @@ xen_hyper_domain_init(void)
> >
> > XEN_HYPER_MEMBER_OFFSET_INIT(domain_is_shutting_down, "domain",
> > "is_shutting_down");
> > XEN_HYPER_MEMBER_OFFSET_INIT(domain_is_shut_down, "domain",
> > "is_shut_down");
> > XEN_HYPER_MEMBER_OFFSET_INIT(domain_vcpu, "domain", "vcpu");
> > + XEN_HYPER_MEMBER_OFFSET_INIT(domain_max_vcpus, "domain",
> > "max_vcpus");
> > XEN_HYPER_MEMBER_OFFSET_INIT(domain_arch, "domain", "arch");
> >
> > XEN_HYPER_STRUCT_SIZE_INIT(arch_shared_info, "arch_shared_info");
> > @@ -1207,6 +1208,8 @@ struct xen_hyper_domain_context *
> > xen_hyper_store_domain_context(struct xen_hyper_domain_context *dc,
> > ulong domain, char *dp)
> > {
> > + unsigned int max_vcpus;
> > + char *vcpup;
> > int i;
> >
> > dc->domain = domain;
> > @@ -1244,9 +1247,40 @@ xen_hyper_store_domain_context(struct xe
> > dc->domain_flags = XEN_HYPER_DOMF_ERROR;
> > }
> > dc->evtchn = ULONG(dp + XEN_HYPER_OFFSET(domain_evtchn));
> > - for (i = 0; i < XEN_HYPER_MAX_VIRT_CPUS; i++) {
> > - dc->vcpu[i] = ULONG(dp + XEN_HYPER_OFFSET(domain_vcpu) +
> > i*sizeof(void *));
> > - if (dc->vcpu[i]) XEN_HYPER_NR_VCPUS_IN_DOM(dc)++;
> > +
> > + if (XEN_HYPER_VALID_MEMBER(domain_max_vcpus)) {
> > + max_vcpus = UINT(dp + XEN_HYPER_OFFSET(domain_max_vcpus));
> > + } else {
> > + max_vcpus = XEN_HYPER_MAX_VIRT_CPUS;
> > + }
> > + if (MEMBER_TYPE("domain", "vcpu") == TYPE_CODE_ARRAY)
> > + vcpup = dp + XEN_HYPER_OFFSET(domain_vcpu);
> > + else {
> > + ulong vcpu_array = ULONG(dp + XEN_HYPER_OFFSET(domain_vcpu));
> > + if (vcpu_array && max_vcpus) {
> > + if (!(vcpup =
> > + malloc(max_vcpus * sizeof(void *)))) {
> > + error(FATAL, "cannot malloc VCPU array for domain %lx.",
> > + domain);
> > + }
> > + if (!readmem(vcpu_array, KVADDR,
> > + vcpup, max_vcpus * sizeof(void*),
> > + "VCPU array", RETURN_ON_ERROR)) {
> > + error(FATAL, "cannot read VCPU array for domain %lx.",
> > + domain);
> > + }
> > + } else {
> > + vcpup = NULL;
> > + }
> > + }
> > + if (vcpup) {
> > + for (i = 0; i < max_vcpus; i++) {
> > + dc->vcpu[i] = ULONG(vcpup + i*sizeof(void *));
> > + if (dc->vcpu[i]) XEN_HYPER_NR_VCPUS_IN_DOM(dc)++;
> > + }
> > + if (vcpup != dp + XEN_HYPER_OFFSET(domain_vcpu)) {
> > + free(vcpup);
> > + }
> > }
> >
> > return dc;
> > --- a/xen_hyper_defs.h
> > +++ b/xen_hyper_defs.h
> > @@ -674,6 +674,7 @@ struct xen_hyper_offset_table {
> > long domain_is_shutting_down;
> > long domain_is_shut_down;
> > long domain_vcpu;
> > + long domain_max_vcpus;
> > long domain_arch;
> > #ifdef IA64
> > /* mm_struct */
> >
> > --
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> > Crash-utility at redhat.com
> > https://www.redhat.com/mailman/listinfo/crash-utility
>
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