Messages in this thread Patch in this message | | | Date | Fri, 9 May 2008 08:06:09 +0200 | From | Heiko Carstens <> | Subject | [PATCH] memory_hotplug: always initialize pageblock bitmap. |
| |
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Trying to online a new memory section that was added via memory hotplug sometimes results in crashes when the new pages are added via __free_page. Reason for that is that the pageblock bitmap isn't initialized and hence contains random stuff. That means that get_pageblock_migratetype() returns also random stuff and therefore
list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
in __free_one_page() tries to do a list_add to something that isn't even necessarily a list. This is only an issue for memory sections that get added after boot time since all previously present memory sections allocate their pageblock bitmaps via the bootmem allocator which in turn initializes just everything it returns.
Cc: Andy Whitcroft <apw@shadowen.org> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> --- mm/sparse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/mm/sparse.c =================================================================== --- linux-2.6.orig/mm/sparse.c +++ linux-2.6/mm/sparse.c @@ -244,7 +244,7 @@ unsigned long usemap_size(void) #ifdef CONFIG_MEMORY_HOTPLUG static unsigned long *__kmalloc_section_usemap(void) { - return kmalloc(usemap_size(), GFP_KERNEL); + return kzalloc(usemap_size(), GFP_KERNEL); } #endif /* CONFIG_MEMORY_HOTPLUG */
| |