This thread relates to an old issue discussed earlier here ... https://www.redhat.com/archives/crash-utility/2008-April/msg00007.html. The following patch currently fixes the issue. The kernel cpu possible,present and online cpu map is not available until cpu_maps_init() initializes them. Hence we remap the nd->nt_prstatus_percpu array to online cpus right after a call to this function.

Signed-off-by: Chandru Siddalingappa <chandru(a)linux.vnet.ibm.com&gt; Cc: Haren Myneni <haren(a)us.ibm.com&gt; --- --- crash-4.0-8.10/ppc64.c.orig 2009-06-08 16:08:09.000000000 +0530 +++ crash-4.0-8.10/ppc64.c 2009-06-08 18:47:04.000000000 +0530 @@ -2407,13 +2407,11 @@ ppc64_paca_init(void) if (!symbol_exists("paca")) error(FATAL, "PPC64: Could not find 'paca' symbol\n"); - if (cpu_map_addr("present")) - map = PRESENT; - else if (cpu_map_addr("online")) - map = ONLINE; + if (cpu_map_addr("possible")) + map = POSSIBLE; else error(FATAL, - "PPC64: cannot find 'cpu_present_map' or 'cpu_online_map' symbols\n"); + "PPC64: cannot find 'cpu_possible_map' symbol\n"); if (!MEMBER_EXISTS("paca_struct", "data_offset")) return;

@@ -2424,7 +2422,7 @@ ppc64_paca_init(void) cpu_paca_buf = GETBUF(SIZE(ppc64_paca)); if (!(nr_paca = get_array_length("paca", NULL, 0))) - nr_paca = NR_CPUS; + nr_paca = kt->kernel_NR_CPUS; if (nr_paca > NR_CPUS) { error(WARNING,

@@ -2435,7 +2433,7 @@ ppc64_paca_init(void) for (i = cpus = 0; i < nr_paca; i++) { /* - * CPU present (or online)? + * CPU in possible map ? */ if (!in_cpu_map(map, i)) continue; --- crash-4.0-8.10/kernel.c.orig 2009-06-08 16:07:53.000000000 +0530 +++ crash-4.0-8.10/kernel.c 2009-06-08 16:48:53.000000000 +0530 @@ -74,6 +74,9 @@ kernel_init() cpu_maps_init(); + if (KDUMP_DUMPFILE()) + map_prstatus_array(); + kt->stext = symbol_value("_stext"); kt->etext = symbol_value("_etext"); get_text_init_space(); --- crash-4.0-8.10/netdump.c.orig 2009-06-08 16:07:58.000000000 +0530 +++ crash-4.0-8.10/netdump.c 2009-06-08 17:40:36.000000000 +0530 @@ -45,6 +45,35 @@ static void check_dumpfile_size(char *); (machine_type("IA64") || machine_type("PPC64")) /* + * kdump installs NT_PRSTATUS elf sections only to the cpus + * that were online during dumping. Hence we call into + * this function after reading the cpu map from the kernel, + * to remap the NT_PRSTATUS sections only to the online cpus + */ +void map_prstatus_array(void) +{ + void *nt_ptr; + int i, j; + + /* temporary buffer to hold the prstatus_percpu array */ + if ((nt_ptr = (void *)calloc(nd->num_prstatus_notes, + sizeof(void *))) == NULL) + error(FATAL, + "cannot allocate a buffer to hold prstatus_percpu array\n"); + + memcpy((void *)nt_ptr, nd->nt_prstatus_percpu, + nd->num_prstatus_notes * sizeof(void *)); + memset(nd->nt_prstatus_percpu, 0, nd->num_prstatus_notes); + + /* re-populate the array with the sections mapping to online cpus */ + for (i = 0, j = 0; i < kt->kernel_NR_CPUS; i++) + if (in_cpu_map(ONLINE, i)) + ((unsigned long *)nd->nt_prstatus_percpu)[i] = + ((unsigned long *)nt_ptr)[j++]; + free(nt_ptr); +}

+ +/* * Determine whether a file is a netdump/diskdump/kdump creation, * and if TRUE, initialize the vmcore_data structure. */ @@ -618,7 +647,7 @@ get_netdump_panic_task(void) crashing_cpu = -1; if (kernel_symbol_exists("crashing_cpu")) { get_symbol_data("crashing_cpu", sizeof(int), &i); - if ((i >= 0) && (i < nd->num_prstatus_notes)) { + if ((i >= 0) && in_cpu_map(ONLINE, i)) { crashing_cpu = i; if (CRASHDEBUG(1)) error(INFO, @@ -2236,7 +2265,7 @@ get_netdump_regs_ppc64(struct bt_info *b * CPUs if they responded to an IPI. */ if (nd->num_prstatus_notes > 1) { - if (bt->tc->processor >= nd->num_prstatus_notes) + if (!nd->nt_prstatus_percpu[bt->tc->processor]) error(FATAL, "cannot determine NT_PRSTATUS ELF note " "for %s task: %lx\n",