[PATCH] powerpc: mem_init crash for sparsemem

Arnd Bergmann
2005-11-04T15:29:47Z

I have a Cell blade with some broken memory in the middle of the
physical address space and this is correctly detected by the
firmware, but not relocated. When I enable CONFIG_SPARSEMEM,
the memsections for the nonexistant address space do not
get struct page entries allocated, as expected.

However, mem_init for the non-NUMA configuration tries to
access these pages without first looking if they are there.
I'm currently using the hack below to work around that, but
I have the feeling that there should be a cleaner solution
for this.

Please comment.

Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>

--- linux-2.6.15-rc.orig/arch/powerpc/mm/mem.c
+++ linux-2.6.15-rc/arch/powerpc/mm/mem.c
@@ -348,6 +348,9 @@ void __init mem_init(void)
#endif
for_each_pgdat(pgdat) {
for (i = 0; i < pgdat->node_spanned_pages; i++) {
+ if (!section_has_mem_map(__pfn_to_section
+ (pgdat->node_start_pfn + i)))
+ continue;
page = pgdat_page_nr(pgdat, i);
if (PageReserved(page))
reservedpages++;