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

[Dave Anderson]

----- Original Message -----
> 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.

Ah, OK, I appreciate that.  Is it something that can be segregated
by the xen version (like the virtual address change)?  That would
make me feel much warmer and fuzzier...

Dave


> 
> 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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