The 2.6.21-rc1 kernel has removed the zone->free_pages member, and replaced it by using the zone->vm_stat[NR_FREE_PAGES] counter. Without this patch, crash will die during initialization with: crash: invalid (optional) structure member offsets: zone_struct_free_pages or zone_free_pages The attached patch to the 4.0-3.20 tree is queued for the next release. Thanks for the report, Dave memory.c symbols.c defs.h --- crash-4.0-3.20/memory.c 2007-02-26 15:34:57.000000000 -0500 +++ crash-next/memory.c 2007-02-26 15:38:51.000000000 -0500 @@ -659,8 +659,17 @@ vt->dump_free_pages = dump_free_pages_zones_v1; } else if (VALID_STRUCT(zone)) { - MEMBER_OFFSET_INIT(zone_free_pages, - "zone", "free_pages"); + MEMBER_OFFSET_INIT(zone_vm_stat, "zone", "vm_stat"); + MEMBER_OFFSET_INIT(zone_free_pages, "zone", "free_pages"); + if (INVALID_MEMBER(zone_free_pages) && + VALID_MEMBER(zone_vm_stat)) { + long nr_free_pages = 0; + if (!enumerator_value("NR_FREE_PAGES", &nr_free_pages)) + error(WARNING, + "cannot determine NR_FREE_PAGES enumerator\n"); + ASSIGN_OFFSET(zone_free_pages) = OFFSET(zone_vm_stat) + + (nr_free_pages * sizeof(long)); + } MEMBER_OFFSET_INIT(zone_free_area, "zone", "free_area"); MEMBER_OFFSET_INIT(zone_zone_pgdat, --- crash-4.0-3.20/symbols.c 2007-02-26 15:34:57.000000000 -0500 +++ crash-next/symbols.c 2007-02-26 14:33:41.000000000 -0500 @@ -6414,6 +6414,8 @@ OFFSET(zone_pages_low)); fprintf(fp, " zone_pages_high: %ld\n", OFFSET(zone_pages_high)); + fprintf(fp, " zone_vm_stat: %ld\n", + OFFSET(zone_vm_stat)); fprintf(fp, " neighbour_next: %ld\n", OFFSET(neighbour_next)); --- crash-4.0-3.20/defs.h 2007-02-26 15:34:57.000000000 -0500 +++ crash-next/defs.h 2007-02-26 14:52:33.000000000 -0500 @@ -1282,6 +1282,7 @@ long zone_pages_min; long zone_pages_low; long zone_pages_high; + long zone_vm_stat; long neighbour_next; long neighbour_primary_key; long neighbour_ha;