This patch improves max_cpus value calculation. First xen_hyper_get_cpu_info() tries to get it from nr_cpu_ids variable. If nr_cpu_ids does not exist then it attempts to read max_cpus variable. If it is not available estimate max_cpus value on the base of cpumask_t size. Signed-off-by: Daniel Kiper <daniel.kiper(a)oracle.com&gt; diff -Npru crash-6.1.0.orig/xen_hyper.c crash-6.1.0/xen_hyper.c --- crash-6.1.0.orig/xen_hyper.c 2012-11-13 15:02:34.000000000 +0100 +++ crash-6.1.0/xen_hyper.c 2012-11-13 15:07:40.000000000 +0100 @@ -1883,13 +1883,28 @@ xen_hyper_get_uptime_hyper(void) void xen_hyper_get_cpu_info(void) { - ulong addr; + ulong addr, init_begin, init_end; ulong *cpumask; uint *cpu_idx; int i, j, cpus; XEN_HYPER_STRUCT_SIZE_INIT(cpumask_t, "cpumask_t"); - xht->max_cpus = XEN_HYPER_SIZE(cpumask_t) * 8; + + if (symbol_exists("nr_cpu_ids")) + get_symbol_data("nr_cpu_ids", sizeof(uint), &xht->max_cpus); + else { + init_begin = symbol_value("__init_begin"); + init_end = symbol_value("__init_end"); + addr = symbol_value("max_cpus"); + + if (addr >= init_begin && addr < init_end) + xht->max_cpus = XEN_HYPER_SIZE(cpumask_t) * 8; + else { + get_symbol_data("max_cpus", sizeof(xht->max_cpus), &xht->max_cpus); + if (XEN_HYPER_SIZE(cpumask_t) * 8 > xht->max_cpus) + xht->max_cpus = XEN_HYPER_SIZE(cpumask_t) * 8; + } + } if (xht->cpumask) { free(xht->cpumask);