per_cpu data is dynamically allocated since 21416 changeset (x86: Dynamically allocate percpu data area when a CPU comes online). Take into account that and read variables from correct address. Signed-off-by: Daniel Kiper <daniel.kiper(a)oracle.com&gt; diff -Npru crash-6.0.8.orig/xen_hyper.c crash-6.0.8/xen_hyper.c --- crash-6.0.8.orig/xen_hyper.c 2012-07-05 15:47:09.000000000 +0200 +++ crash-6.0.8/xen_hyper.c 2012-07-05 15:50:19.000000000 +0200 @@ -64,7 +64,6 @@ xen_hyper_init(void) machdep->get_smp_cpus(); machdep->memory_size(); -#ifdef IA64 if (symbol_exists("__per_cpu_offset")) { xht->flags |= XEN_HYPER_SMP; if((xht->__per_cpu_offset = malloc(sizeof(ulong) * XEN_HYPER_MAX_CPUS())) == NULL) { @@ -76,7 +75,6 @@ xen_hyper_init(void) error(FATAL, "cannot read __per_cpu_offset.\n"); } } -#endif #if defined(X86) || defined(X86_64) if (symbol_exists("__per_cpu_shift")) { diff -Npru crash-6.0.8.orig/xen_hyper_defs.h crash-6.0.8/xen_hyper_defs.h --- crash-6.0.8.orig/xen_hyper_defs.h 2012-06-29 16:59:18.000000000 +0200 +++ crash-6.0.8/xen_hyper_defs.h 2012-07-05 15:50:19.000000000 +0200 @@ -136,7 +136,13 @@ typedef uint32_t Elf_Word; #if defined(X86) || defined(X86_64) #define xen_hyper_per_cpu(var, cpu) \ - ((ulong)(var) + (((ulong)(cpu))<<xht->percpu_shift)) + ({ ulong __var_addr; \ + if (xht->__per_cpu_offset) \ + __var_addr = (xht->flags & XEN_HYPER_SMP) ? \ + ((ulong)(var) + xht->__per_cpu_offset[cpu]) : (ulong)(var); \ + else \ + __var_addr = (ulong)(var) + ((ulong)(cpu) << xht->percpu_shift); \ + __var_addr; }) #elif defined(IA64) #define xen_hyper_per_cpu(var, cpu) \ ((xht->flags & XEN_HYPER_SMP) ? \