diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/Kconfig.debug | 1 | ||||
| -rw-r--r-- | mm/Makefile | 1 | ||||
| -rw-r--r-- | mm/kmemcheck.c | 122 | ||||
| -rw-r--r-- | mm/page_alloc.c | 18 | ||||
| -rw-r--r-- | mm/slab.c | 108 | ||||
| -rw-r--r-- | mm/slub.c | 38 |
6 files changed, 200 insertions, 88 deletions
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index bb01e298f260..aa99fd1f7109 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -2,6 +2,7 @@ config DEBUG_PAGEALLOC bool "Debug page memory allocations" depends on DEBUG_KERNEL && ARCH_SUPPORTS_DEBUG_PAGEALLOC depends on !HIBERNATION || !PPC && !SPARC + depends on !KMEMCHECK ---help--- Unmap pages from the kernel linear mapping after free_pages(). This results in a large slowdown, but helps to find certain types diff --git a/mm/Makefile b/mm/Makefile index e89acb090b4d..c379ce08354a 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -27,6 +27,7 @@ obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o obj-$(CONFIG_PAGE_POISONING) += debug-pagealloc.o obj-$(CONFIG_SLAB) += slab.o obj-$(CONFIG_SLUB) += slub.o +obj-$(CONFIG_KMEMCHECK) += kmemcheck.o obj-$(CONFIG_FAILSLAB) += failslab.o obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o obj-$(CONFIG_FS_XIP) += filemap_xip.o diff --git a/mm/kmemcheck.c b/mm/kmemcheck.c new file mode 100644 index 000000000000..fd814fd61319 --- /dev/null +++ b/mm/kmemcheck.c @@ -0,0 +1,122 @@ +#include <linux/gfp.h> +#include <linux/mm_types.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/kmemcheck.h> + +void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node) +{ + struct page *shadow; + int pages; + int i; + + pages = 1 << order; + + /* + * With kmemcheck enabled, we need to allocate a memory area for the + * shadow bits as well. + */ + shadow = alloc_pages_node(node, flags | __GFP_NOTRACK, order); + if (!shadow) { + if (printk_ratelimit()) + printk(KERN_ERR "kmemcheck: failed to allocate " + "shadow bitmap\n"); + return; + } + + for(i = 0; i < pages; ++i) + page[i].shadow = page_address(&shadow[i]); + + /* + * Mark it as non-present for the MMU so that our accesses to + * this memory will trigger a page fault and let us analyze + * the memory accesses. + */ + kmemcheck_hide_pages(page, pages); +} + +void kmemcheck_free_shadow(struct page *page, int order) +{ + struct page *shadow; + int pages; + int i; + + if (!kmemcheck_page_is_tracked(page)) + return; + + pages = 1 << order; + + kmemcheck_show_pages(page, pages); + + shadow = virt_to_page(page[0].shadow); + + for(i = 0; i < pages; ++i) + page[i].shadow = NULL; + + __free_pages(shadow, order); +} + +void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object, + size_t size) +{ + /* + * Has already been memset(), which initializes the shadow for us + * as well. + */ + if (gfpflags & __GFP_ZERO) + return; + + /* No need to initialize the shadow of a non-tracked slab. */ + if (s->flags & SLAB_NOTRACK) + return; + + if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) { + /* + * Allow notracked objects to be allocated from + * tracked caches. Note however that these objects + * will still get page faults on access, they just + * won't ever be flagged as uninitialized. If page + * faults are not acceptable, the slab cache itself + * should be marked NOTRACK. + */ + kmemcheck_mark_initialized(object, size); + } else if (!s->ctor) { + /* + * New objects should be marked uninitialized before + * they're returned to the called. + */ + kmemcheck_mark_uninitialized(object, size); + } +} + +void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size) +{ + /* TODO: RCU freeing is unsupported for now; hide false positives. */ + if (!s->ctor && !(s->flags & SLAB_DESTROY_BY_RCU)) + kmemcheck_mark_freed(object, size); +} + +void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order, + gfp_t gfpflags) +{ + int pages; + + if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK)) + return; + + pages = 1 << order; + + /* + * NOTE: We choose to track GFP_ZERO pages too; in fact, they + * can become uninitialized by copying uninitialized memory + * into them. + */ + + /* XXX: Can use zone->node for node? */ + kmemcheck_alloc_shadow(page, order, gfpflags, -1); + + if (gfpflags & __GFP_ZERO) + kmemcheck_mark_initialized_pages(page, pages); + else + kmemcheck_mark_uninitialized_pages(page, pages); +} diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 17d5f539a9aa..0727896a88ac 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -23,6 +23,7 @@ #include <linux/bootmem.h> #include <linux/compiler.h> #include <linux/kernel.h> +#include <linux/kmemcheck.h> #include <linux/module.h> #include <linux/suspend.h> #include <linux/pagevec.h> @@ -546,6 +547,8 @@ static void __free_pages_ok(struct page *page, unsigned int order) int i; int bad = 0; + kmemcheck_free_shadow(page, order); + for (i = 0 ; i < (1 << order) ; ++i) bad += free_pages_check(page + i); if (bad) @@ -994,6 +997,8 @@ static void free_hot_cold_page(struct page *page, int cold) struct per_cpu_pages *pcp; unsigned long flags; + kmemcheck_free_shadow(page, 0); + if (PageAnon(page)) page->mapping = NULL; if (free_pages_check(page)) @@ -1047,6 +1052,16 @@ void split_page(struct page *page, unsigned int order) VM_BUG_ON(PageCompound(page)); VM_BUG_ON(!page_count(page)); + +#ifdef CONFIG_KMEMCHECK + /* + * Split shadow pages too, because free(page[0]) would + * otherwise free the whole shadow. + */ + if (kmemcheck_page_is_tracked(page)) + split_page(virt_to_page(page[0].shadow), order); +#endif + for (i = 1; i < (1 << order); i++) set_page_refcounted(page + i); } @@ -1667,7 +1682,10 @@ nopage: dump_stack(); show_mem(); } + return page; got_pg: + if (kmemcheck_enabled) + kmemcheck_pagealloc_alloc(page, order, gfp_mask); return page; } EXPORT_SYMBOL(__alloc_pages_internal); diff --git a/mm/slab.c b/mm/slab.c index 18e3164de09a..af3376d0a833 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -114,6 +114,7 @@ #include <linux/rtmutex.h> #include <linux/reciprocal_div.h> #include <linux/debugobjects.h> +#include <linux/kmemcheck.h> #include <asm/cacheflush.h> #include <asm/tlbflush.h> @@ -179,13 +180,13 @@ SLAB_STORE_USER | \ SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \ - SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE) + SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK) #else # define CREATE_MASK (SLAB_HWCACHE_ALIGN | \ SLAB_CACHE_DMA | \ SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \ - SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE) + SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK) #endif /* @@ -380,87 +381,6 @@ static void kmem_list3_init(struct kmem_list3 *parent) MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \ } while (0) -/* - * struct kmem_cache - * - * manages a cache. - */ - -struct kmem_cache { -/* 1) per-cpu data, touched during every alloc/free */ - struct array_cache *array[NR_CPUS]; -/* 2) Cache tunables. Protected by cache_chain_mutex */ - unsigned int batchcount; - unsigned int limit; - unsigned int shared; - - unsigned int buffer_size; - u32 reciprocal_buffer_size; -/* 3) touched by every alloc & free from the backend */ - - unsigned int flags; /* constant flags */ - unsigned int num; /* # of objs per slab */ - -/* 4) cache_grow/shrink */ - /* order of pgs per slab (2^n) */ - unsigned int gfporder; - - /* force GFP flags, e.g. GFP_DMA */ - gfp_t gfpflags; - - size_t colour; /* cache colouring range */ - unsigned int colour_off; /* colour offset */ - struct kmem_cache *slabp_cache; - unsigned int slab_size; - unsigned int dflags; /* dynamic flags */ - - /* constructor func */ - void (*ctor)(void *obj); - -/* 5) cache creation/removal */ - const char *name; - struct list_head next; - -/* 6) statistics */ -#if STATS - unsigned long num_active; - unsigned long num_allocations; - unsigned long high_mark; - unsigned long grown; - unsigned long reaped; - unsigned long errors; - unsigned long max_freeable; - unsigned long node_allocs; - unsigned long node_frees; - unsigned long node_overflow; - atomic_t allochit; - atomic_t allocmiss; - atomic_t freehit; - atomic_t freemiss; -#endif -#if DEBUG - /* - * If debugging is enabled, then the allocator can add additional - * fields and/or padding to every object. buffer_size contains the total - * object size including these internal fields, the following two - * variables contain the offset to the user object and its size. - */ - int obj_offset; - int obj_size; -#endif - /* - * We put nodelists[] at the end of kmem_cache, because we want to size - * this array to nr_node_ids slots instead of MAX_NUMNODES - * (see kmem_cache_init()) - * We still use [MAX_NUMNODES] and not [1] or [0] because cache_cache - * is statically defined, so we reserve the max number of nodes. - */ - struct kmem_list3 *nodelists[MAX_NUMNODES]; - /* - * Do not add fields after nodelists[] - */ -}; - #define CFLGS_OFF_SLAB (0x80000000UL) #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB) @@ -1707,7 +1627,7 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) if (cachep->flags & SLAB_RECLAIM_ACCOUNT) flags |= __GFP_RECLAIMABLE; - page = alloc_pages_node(nodeid, flags, cachep->gfporder); + page = alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder); if (!page) return NULL; @@ -1720,6 +1640,16 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) NR_SLAB_UNRECLAIMABLE, nr_pages); for (i = 0; i < nr_pages; i++) __SetPageSlab(page + i); + + if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) { + kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid); + + if (cachep->ctor) + kmemcheck_mark_uninitialized_pages(page, nr_pages); + else + kmemcheck_mark_unallocated_pages(page, nr_pages); + } + return page_address(page); } @@ -1732,6 +1662,8 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr) struct page *page = virt_to_page(addr); const unsigned long nr_freed = i; + kmemcheck_free_shadow(page, cachep->gfporder); + if (cachep->flags & SLAB_RECLAIM_ACCOUNT) sub_zone_page_state(page_zone(page), NR_SLAB_RECLAIMABLE, nr_freed); @@ -3407,6 +3339,9 @@ __cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags, flags); + if (likely(ptr)) + kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep)); + if (unlikely((flags & __GFP_ZERO) && ptr)) memset(ptr, 0, obj_size(cachep)); @@ -3467,6 +3402,9 @@ __cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller) flags); prefetchw(objp); + if (likely(objp)) + kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep)); + if (unlikely((flags & __GFP_ZERO) && objp)) memset(objp, 0, obj_size(cachep)); @@ -3583,6 +3521,8 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp) kmemleak_free_recursive(objp, cachep->flags); objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0)); + kmemcheck_slab_free(cachep, objp, obj_size(cachep)); + /* * Skip calling cache_free_alien() when the platform is not numa. * This will avoid cache misses that happen while accessing slabp (which diff --git a/mm/slub.c b/mm/slub.c index 30354bfeb43d..15960a09abb1 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -18,6 +18,7 @@ #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/kmemtrace.h> +#include <linux/kmemcheck.h> #include <linux/cpu.h> #include <linux/cpuset.h> #include <linux/kmemleak.h> @@ -147,7 +148,7 @@ SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE) #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \ - SLAB_CACHE_DMA) + SLAB_CACHE_DMA | SLAB_NOTRACK) #ifndef ARCH_KMALLOC_MINALIGN #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) @@ -1071,6 +1072,8 @@ static inline struct page *alloc_slab_page(gfp_t flags, int node, { int order = oo_order(oo); + flags |= __GFP_NOTRACK; + if (node == -1) return alloc_pages(flags, order); else @@ -1098,6 +1101,24 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) stat(get_cpu_slab(s, raw_smp_processor_id()), ORDER_FALLBACK); } + + if (kmemcheck_enabled + && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) + { + int pages = 1 << oo_order(oo); + + kmemcheck_alloc_shadow(page, oo_order(oo), flags, node); + + /* + * Objects from caches that have a constructor don't get + * cleared when they're allocated, so we need to do it here. + */ + if (s->ctor) + kmemcheck_mark_uninitialized_pages(page, pages); + else + kmemcheck_mark_unallocated_pages(page, pages); + } + page->objects = oo_objects(oo); mod_zone_page_state(page_zone(page), (s->flags & SLAB_RECLAIM_ACCOUNT) ? @@ -1171,6 +1192,8 @@ static void __free_slab(struct kmem_cache *s, struct page *page) __ClearPageSlubDebug(page); } + kmemcheck_free_shadow(page, compound_order(page)); + mod_zone_page_state(page_zone(page), (s->flags & SLAB_RECLAIM_ACCOUNT) ? NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, @@ -1626,7 +1649,9 @@ static __always_inline void *slab_alloc(struct kmem_cache *s, if (unlikely((gfpflags & __GFP_ZERO) && object)) memset(object, 0, objsize); + kmemcheck_slab_alloc(s, gfpflags, object, c->objsize); kmemleak_alloc_recursive(object, objsize, 1, s->flags, gfpflags); + return object; } @@ -1759,6 +1784,7 @@ static __always_inline void slab_free(struct kmem_cache *s, kmemleak_free_recursive(x, s->flags); local_irq_save(flags); c = get_cpu_slab(s, smp_processor_id()); + kmemcheck_slab_free(s, object, c->objsize); debug_check_no_locks_freed(object, c->objsize); if (!(s->flags & SLAB_DEBUG_OBJECTS)) debug_check_no_obj_freed(object, c->objsize); @@ -2633,7 +2659,8 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags) if (!s || !text || !kmem_cache_open(s, flags, text, realsize, ARCH_KMALLOC_MINALIGN, - SLAB_CACHE_DMA|__SYSFS_ADD_DEFERRED, NULL)) { + SLAB_CACHE_DMA|SLAB_NOTRACK|__SYSFS_ADD_DEFERRED, + NULL)) { kfree(s); kfree(text); goto unlock_out; @@ -2727,9 +2754,10 @@ EXPORT_SYMBOL(__kmalloc); static void *kmalloc_large_node(size_t size, gfp_t flags, int node) { - struct page *page = alloc_pages_node(node, flags | __GFP_COMP, - get_order(size)); + struct page *page; + flags |= __GFP_COMP | __GFP_NOTRACK; + page = alloc_pages_node(node, flags, get_order(size)); if (page) return page_address(page); else @@ -4412,6 +4440,8 @@ static char *create_unique_id(struct kmem_cache *s) *p++ = 'a'; if (s->flags & SLAB_DEBUG_FREE) *p++ = 'F'; + if (!(s->flags & SLAB_NOTRACK)) + *p++ = 't'; if (p != name + 1) *p++ = '-'; p += sprintf(p, "%07d", s->size); |