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 <hugh@veritas.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e76cf94..402a504 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -222,13 +222,19 @@
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 @@
{
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 @@
{
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 @@
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 @@
set_page_links(page, zone, nid, pfn);
init_page_count(page);
reset_page_mapcount(page);
- page_assign_page_cgroup(page, NULL);
SetPageReserved(page);
/*