From 9442ec9df40d952b0de185ae5638a74970388e01 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 4 Mar 2008 14:29:07 -0800 Subject: memcg: bad page if page_cgroup when free Replace free_hot_cold_page's VM_BUG_ON(page_get_page_cgroup(page)) by a "Bad page state" and clear: most users don't have CONFIG_DEBUG_VM on, and if it were set here, it'd likely cause corruption when the page is reused. Don't use page_assign_page_cgroup to clear it: that should be private to memcontrol.c, and always called with the lock taken; and memmap_init_zone doesn't need it either - like page->mapping and other pointers throughout the kernel, Linux assumes pointers in zeroed structures are NULL pointers. Instead use page_reset_bad_cgroup, added to memcontrol.h for this only. Signed-off-by: Hugh Dickins Cc: David Rientjes Acked-by: Balbir Singh Acked-by: KAMEZAWA Hiroyuki Cc: Hirokazu Takahashi Cc: YAMAMOTO Takashi Cc: Paul Menage Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e76cf94725c9..402a504f1228 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -222,13 +222,19 @@ static inline int bad_range(struct zone *zone, struct page *page) static void bad_page(struct page *page) { - printk(KERN_EMERG "Bad page state in process '%s'\n" - KERN_EMERG "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n" - KERN_EMERG "Trying to fix it up, but a reboot is needed\n" - KERN_EMERG "Backtrace:\n", + void *pc = page_get_page_cgroup(page); + + printk(KERN_EMERG "Bad page state in process '%s'\n" KERN_EMERG + "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n", current->comm, page, (int)(2*sizeof(unsigned long)), (unsigned long)page->flags, page->mapping, page_mapcount(page), page_count(page)); + if (pc) { + printk(KERN_EMERG "cgroup:%p\n", pc); + page_reset_bad_cgroup(page); + } + printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n" + KERN_EMERG "Backtrace:\n"); dump_stack(); page->flags &= ~(1 << PG_lru | 1 << PG_private | @@ -454,6 +460,7 @@ static inline int free_pages_check(struct page *page) { if (unlikely(page_mapcount(page) | (page->mapping != NULL) | + (page_get_page_cgroup(page) != NULL) | (page_count(page) != 0) | (page->flags & ( 1 << PG_lru | @@ -603,6 +610,7 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags) { if (unlikely(page_mapcount(page) | (page->mapping != NULL) | + (page_get_page_cgroup(page) != NULL) | (page_count(page) != 0) | (page->flags & ( 1 << PG_lru | @@ -989,7 +997,6 @@ static void free_hot_cold_page(struct page *page, int cold) if (!PageHighMem(page)) debug_check_no_locks_freed(page_address(page), PAGE_SIZE); - VM_BUG_ON(page_get_page_cgroup(page)); arch_free_page(page, 0); kernel_map_pages(page, 1, 0); @@ -2528,7 +2535,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, set_page_links(page, zone, nid, pfn); init_page_count(page); reset_page_mapcount(page); - page_assign_page_cgroup(page, NULL); SetPageReserved(page); /* -- cgit v1.2.3