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>
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@ -29,8 +29,9 @@ struct mm_struct;
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extern void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p);
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extern void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p);
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extern void mm_free_cgroup(struct mm_struct *mm);
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extern void mm_free_cgroup(struct mm_struct *mm);
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extern void page_assign_page_cgroup(struct page *page,
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struct page_cgroup *pc);
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#define page_reset_bad_cgroup(page) ((page)->page_cgroup = 0)
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extern struct page_cgroup *page_get_page_cgroup(struct page *page);
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extern struct page_cgroup *page_get_page_cgroup(struct page *page);
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extern int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
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extern int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
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gfp_t gfp_mask);
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gfp_t gfp_mask);
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@ -82,8 +83,7 @@ static inline void mm_free_cgroup(struct mm_struct *mm)
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{
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{
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}
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}
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static inline void page_assign_page_cgroup(struct page *page,
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static inline void page_reset_bad_cgroup(struct page *page)
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struct page_cgroup *pc)
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{
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{
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}
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}
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@ -140,11 +140,17 @@ struct mem_cgroup {
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/*
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/*
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* We use the lower bit of the page->page_cgroup pointer as a bit spin
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* We use the lower bit of the page->page_cgroup pointer as a bit spin
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* lock. We need to ensure that page->page_cgroup is atleast two
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* lock. We need to ensure that page->page_cgroup is at least two
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* byte aligned (based on comments from Nick Piggin)
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* byte aligned (based on comments from Nick Piggin). But since
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* bit_spin_lock doesn't actually set that lock bit in a non-debug
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* uniprocessor kernel, we should avoid setting it here too.
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*/
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*/
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#define PAGE_CGROUP_LOCK_BIT 0x0
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#define PAGE_CGROUP_LOCK_BIT 0x0
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#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT)
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#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
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#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT)
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#else
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#define PAGE_CGROUP_LOCK 0x0
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#endif
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/*
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/*
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* A page_cgroup page is associated with every page descriptor. The
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* A page_cgroup page is associated with every page descriptor. The
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@ -271,19 +277,10 @@ static inline int page_cgroup_locked(struct page *page)
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&page->page_cgroup);
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&page->page_cgroup);
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}
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}
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void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
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static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
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{
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{
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int locked;
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VM_BUG_ON(!page_cgroup_locked(page));
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page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK);
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/*
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* While resetting the page_cgroup we might not hold the
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* page_cgroup lock. free_hot_cold_page() is an example
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* of such a scenario
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*/
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if (pc)
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VM_BUG_ON(!page_cgroup_locked(page));
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locked = (page->page_cgroup & PAGE_CGROUP_LOCK);
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page->page_cgroup = ((unsigned long)pc | locked);
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}
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}
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struct page_cgroup *page_get_page_cgroup(struct page *page)
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struct page_cgroup *page_get_page_cgroup(struct page *page)
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@ -222,13 +222,19 @@ static inline int bad_range(struct zone *zone, struct page *page)
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static void bad_page(struct page *page)
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static void bad_page(struct page *page)
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{
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{
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printk(KERN_EMERG "Bad page state in process '%s'\n"
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void *pc = page_get_page_cgroup(page);
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KERN_EMERG "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
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KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
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printk(KERN_EMERG "Bad page state in process '%s'\n" KERN_EMERG
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KERN_EMERG "Backtrace:\n",
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"page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n",
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current->comm, page, (int)(2*sizeof(unsigned long)),
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current->comm, page, (int)(2*sizeof(unsigned long)),
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(unsigned long)page->flags, page->mapping,
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(unsigned long)page->flags, page->mapping,
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page_mapcount(page), page_count(page));
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page_mapcount(page), page_count(page));
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if (pc) {
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printk(KERN_EMERG "cgroup:%p\n", pc);
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page_reset_bad_cgroup(page);
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}
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printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
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KERN_EMERG "Backtrace:\n");
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dump_stack();
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dump_stack();
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page->flags &= ~(1 << PG_lru |
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page->flags &= ~(1 << PG_lru |
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1 << PG_private |
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1 << PG_private |
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@ -454,6 +460,7 @@ static inline int free_pages_check(struct page *page)
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{
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{
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if (unlikely(page_mapcount(page) |
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if (unlikely(page_mapcount(page) |
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(page->mapping != NULL) |
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(page->mapping != NULL) |
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(page_get_page_cgroup(page) != NULL) |
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(page_count(page) != 0) |
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(page_count(page) != 0) |
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(page->flags & (
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(page->flags & (
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1 << PG_lru |
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1 << PG_lru |
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@ -603,6 +610,7 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
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{
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{
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if (unlikely(page_mapcount(page) |
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if (unlikely(page_mapcount(page) |
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(page->mapping != NULL) |
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(page->mapping != NULL) |
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(page_get_page_cgroup(page) != NULL) |
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(page_count(page) != 0) |
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(page_count(page) != 0) |
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(page->flags & (
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(page->flags & (
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1 << PG_lru |
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1 << PG_lru |
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@ -989,7 +997,6 @@ static void free_hot_cold_page(struct page *page, int cold)
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if (!PageHighMem(page))
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if (!PageHighMem(page))
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debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
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debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
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VM_BUG_ON(page_get_page_cgroup(page));
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arch_free_page(page, 0);
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arch_free_page(page, 0);
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kernel_map_pages(page, 1, 0);
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kernel_map_pages(page, 1, 0);
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@ -2528,7 +2535,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
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set_page_links(page, zone, nid, pfn);
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set_page_links(page, zone, nid, pfn);
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init_page_count(page);
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init_page_count(page);
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reset_page_mapcount(page);
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reset_page_mapcount(page);
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page_assign_page_cgroup(page, NULL);
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SetPageReserved(page);
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SetPageReserved(page);
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/*
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/*
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