]> err.no Git - linux-2.6/blobdiff - mm/slub.c
SLUB Debug: fix initial object debug state of NUMA bootstrap objects
[linux-2.6] / mm / slub.c
index 6aea48942c29b3e2ada3a551d5382cc88e474539..a18708821c1e2264eea914a4f45c2bafec04337e 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -205,6 +205,11 @@ static inline void ClearSlabDebug(struct page *page)
 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 #endif
 
+/*
+ * The page->inuse field is 16 bit thus we have this limitation
+ */
+#define MAX_OBJECTS_PER_SLAB 65535
+
 /* Internal SLUB flags */
 #define __OBJECT_POISON 0x80000000     /* Poison object */
 
@@ -344,7 +349,7 @@ static void print_section(char *text, u8 *addr, unsigned int length)
 
        for (i = 0; i < length; i++) {
                if (newline) {
-                       printk(KERN_ERR "%10s 0x%p: ", text, addr + i);
+                       printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
                        newline = 0;
                }
                printk(" %02x", addr[i]);
@@ -401,10 +406,11 @@ static void set_track(struct kmem_cache *s, void *object,
 
 static void init_tracking(struct kmem_cache *s, void *object)
 {
-       if (s->flags & SLAB_STORE_USER) {
-               set_track(s, object, TRACK_FREE, NULL);
-               set_track(s, object, TRACK_ALLOC, NULL);
-       }
+       if (!(s->flags & SLAB_STORE_USER))
+               return;
+
+       set_track(s, object, TRACK_FREE, NULL);
+       set_track(s, object, TRACK_ALLOC, NULL);
 }
 
 static void print_track(const char *s, struct track *t)
@@ -412,65 +418,106 @@ static void print_track(const char *s, struct track *t)
        if (!t->addr)
                return;
 
-       printk(KERN_ERR "%s: ", s);
+       printk(KERN_ERR "INFO: %s in ", s);
        __print_symbol("%s", (unsigned long)t->addr);
-       printk(" jiffies_ago=%lu cpu=%u pid=%d\n", jiffies - t->when, t->cpu, t->pid);
+       printk(" age=%lu cpu=%u pid=%d\n", jiffies - t->when, t->cpu, t->pid);
+}
+
+static void print_tracking(struct kmem_cache *s, void *object)
+{
+       if (!(s->flags & SLAB_STORE_USER))
+               return;
+
+       print_track("Allocated", get_track(s, object, TRACK_ALLOC));
+       print_track("Freed", get_track(s, object, TRACK_FREE));
+}
+
+static void print_page_info(struct page *page)
+{
+       printk(KERN_ERR "INFO: Slab 0x%p used=%u fp=0x%p flags=0x%04lx\n",
+               page, page->inuse, page->freelist, page->flags);
+
+}
+
+static void slab_bug(struct kmem_cache *s, char *fmt, ...)
+{
+       va_list args;
+       char buf[100];
+
+       va_start(args, fmt);
+       vsnprintf(buf, sizeof(buf), fmt, args);
+       va_end(args);
+       printk(KERN_ERR "========================================"
+                       "=====================================\n");
+       printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
+       printk(KERN_ERR "----------------------------------------"
+                       "-------------------------------------\n\n");
+}
+
+static void slab_fix(struct kmem_cache *s, char *fmt, ...)
+{
+       va_list args;
+       char buf[100];
+
+       va_start(args, fmt);
+       vsnprintf(buf, sizeof(buf), fmt, args);
+       va_end(args);
+       printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
 }
 
-static void print_trailer(struct kmem_cache *s, u8 *p)
+static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 {
        unsigned int off;       /* Offset of last byte */
+       u8 *addr = page_address(page);
+
+       print_tracking(s, p);
+
+       print_page_info(page);
+
+       printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
+                       p, p - addr, get_freepointer(s, p));
+
+       if (p > addr + 16)
+               print_section("Bytes b4", p - 16, 16);
+
+       print_section("Object", p, min(s->objsize, 128));
 
        if (s->flags & SLAB_RED_ZONE)
                print_section("Redzone", p + s->objsize,
                        s->inuse - s->objsize);
 
-       printk(KERN_ERR "FreePointer 0x%p -> 0x%p\n",
-                       p + s->offset,
-                       get_freepointer(s, p));
-
        if (s->offset)
                off = s->offset + sizeof(void *);
        else
                off = s->inuse;
 
-       if (s->flags & SLAB_STORE_USER) {
-               print_track("Last alloc", get_track(s, p, TRACK_ALLOC));
-               print_track("Last free ", get_track(s, p, TRACK_FREE));
+       if (s->flags & SLAB_STORE_USER)
                off += 2 * sizeof(struct track);
-       }
 
        if (off != s->size)
                /* Beginning of the filler is the free pointer */
-               print_section("Filler", p + off, s->size - off);
+               print_section("Padding", p + off, s->size - off);
+
+       dump_stack();
 }
 
 static void object_err(struct kmem_cache *s, struct page *page,
                        u8 *object, char *reason)
 {
-       u8 *addr = page_address(page);
-
-       printk(KERN_ERR "*** SLUB %s: %s@0x%p slab 0x%p\n",
-                       s->name, reason, object, page);
-       printk(KERN_ERR "    offset=%tu flags=0x%04lx inuse=%u freelist=0x%p\n",
-               object - addr, page->flags, page->inuse, page->freelist);
-       if (object > addr + 16)
-               print_section("Bytes b4", object - 16, 16);
-       print_section("Object", object, min(s->objsize, 128));
-       print_trailer(s, object);
-       dump_stack();
+       slab_bug(s, reason);
+       print_trailer(s, page, object);
 }
 
-static void slab_err(struct kmem_cache *s, struct page *page, char *reason, ...)
+static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
 {
        va_list args;
        char buf[100];
 
-       va_start(args, reason);
-       vsnprintf(buf, sizeof(buf), reason, args);
+       va_start(args, fmt);
+       vsnprintf(buf, sizeof(buf), fmt, args);
        va_end(args);
-       printk(KERN_ERR "*** SLUB %s: %s in slab @0x%p\n", s->name, buf,
-               page);
+       slab_bug(s, fmt);
+       print_page_info(page);
        dump_stack();
 }
 
@@ -489,15 +536,46 @@ static void init_object(struct kmem_cache *s, void *object, int active)
                        s->inuse - s->objsize);
 }
 
-static int check_bytes(u8 *start, unsigned int value, unsigned int bytes)
+static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
 {
        while (bytes) {
                if (*start != (u8)value)
-                       return 0;
+                       return start;
                start++;
                bytes--;
        }
-       return 1;
+       return NULL;
+}
+
+static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
+                                               void *from, void *to)
+{
+       slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
+       memset(from, data, to - from);
+}
+
+static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
+                       u8 *object, char *what,
+                       u8* start, unsigned int value, unsigned int bytes)
+{
+       u8 *fault;
+       u8 *end;
+
+       fault = check_bytes(start, value, bytes);
+       if (!fault)
+               return 1;
+
+       end = start + bytes;
+       while (end > fault && end[-1] == value)
+               end--;
+
+       slab_bug(s, "%s overwritten", what);
+       printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
+                                       fault, end - 1, fault[0], value);
+       print_trailer(s, page, object);
+
+       restore_bytes(s, what, value, fault, end);
+       return 0;
 }
 
 /*
@@ -538,14 +616,6 @@ static int check_bytes(u8 *start, unsigned int value, unsigned int bytes)
  * may be used with merged slabcaches.
  */
 
-static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
-                                               void *from, void *to)
-{
-       printk(KERN_ERR "@@@ SLUB %s: Restoring %s (0x%x) from 0x%p-0x%p\n",
-               s->name, message, data, from, to - 1);
-       memset(from, data, to - from);
-}
-
 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
 {
        unsigned long off = s->inuse;   /* The end of info */
@@ -561,39 +631,39 @@ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
        if (s->size == off)
                return 1;
 
-       if (check_bytes(p + off, POISON_INUSE, s->size - off))
-               return 1;
-
-       object_err(s, page, p, "Object padding check fails");
-
-       /*
-        * Restore padding
-        */
-       restore_bytes(s, "object padding", POISON_INUSE, p + off, p + s->size);
-       return 0;
+       return check_bytes_and_report(s, page, p, "Object padding",
+                               p + off, POISON_INUSE, s->size - off);
 }
 
 static int slab_pad_check(struct kmem_cache *s, struct page *page)
 {
-       u8 *p;
-       int length, remainder;
+       u8 *start;
+       u8 *fault;
+       u8 *end;
+       int length;
+       int remainder;
 
        if (!(s->flags & SLAB_POISON))
                return 1;
 
-       p = page_address(page);
+       start = page_address(page);
+       end = start + (PAGE_SIZE << s->order);
        length = s->objects * s->size;
-       remainder = (PAGE_SIZE << s->order) - length;
+       remainder = end - (start + length);
        if (!remainder)
                return 1;
 
-       if (!check_bytes(p + length, POISON_INUSE, remainder)) {
-               slab_err(s, page, "Padding check failed");
-               restore_bytes(s, "slab padding", POISON_INUSE, p + length,
-                       p + length + remainder);
-               return 0;
-       }
-       return 1;
+       fault = check_bytes(start + length, POISON_INUSE, remainder);
+       if (!fault)
+               return 1;
+       while (end > fault && end[-1] == POISON_INUSE)
+               end--;
+
+       slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
+       print_section("Padding", start, length);
+
+       restore_bytes(s, "slab padding", POISON_INUSE, start, end);
+       return 0;
 }
 
 static int check_object(struct kmem_cache *s, struct page *page,
@@ -606,41 +676,22 @@ static int check_object(struct kmem_cache *s, struct page *page,
                unsigned int red =
                        active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE;
 
-               if (!check_bytes(endobject, red, s->inuse - s->objsize)) {
-                       object_err(s, page, object,
-                       active ? "Redzone Active" : "Redzone Inactive");
-                       restore_bytes(s, "redzone", red,
-                               endobject, object + s->inuse);
+               if (!check_bytes_and_report(s, page, object, "Redzone",
+                       endobject, red, s->inuse - s->objsize))
                        return 0;
-               }
        } else {
-               if ((s->flags & SLAB_POISON) && s->objsize < s->inuse &&
-                       !check_bytes(endobject, POISON_INUSE,
-                                       s->inuse - s->objsize)) {
-               object_err(s, page, p, "Alignment padding check fails");
-               /*
-                * Fix it so that there will not be another report.
-                *
-                * Hmmm... We may be corrupting an object that now expects
-                * to be longer than allowed.
-                */
-               restore_bytes(s, "alignment padding", POISON_INUSE,
-                       endobject, object + s->inuse);
-               }
+               if ((s->flags & SLAB_POISON) && s->objsize < s->inuse)
+                       check_bytes_and_report(s, page, p, "Alignment padding", endobject,
+                               POISON_INUSE, s->inuse - s->objsize);
        }
 
        if (s->flags & SLAB_POISON) {
                if (!active && (s->flags & __OBJECT_POISON) &&
-                       (!check_bytes(p, POISON_FREE, s->objsize - 1) ||
-                               p[s->objsize - 1] != POISON_END)) {
-
-                       object_err(s, page, p, "Poison check failed");
-                       restore_bytes(s, "Poison", POISON_FREE,
-                                               p, p + s->objsize -1);
-                       restore_bytes(s, "Poison", POISON_END,
-                                       p + s->objsize - 1, p + s->objsize);
+                       (!check_bytes_and_report(s, page, p, "Poison", p,
+                                       POISON_FREE, s->objsize - 1) ||
+                        !check_bytes_and_report(s, page, p, "Poison",
+                               p + s->objsize -1, POISON_END, 1)))
                        return 0;
-               }
                /*
                 * check_pad_bytes cleans up on its own.
                 */
@@ -673,25 +724,17 @@ static int check_slab(struct kmem_cache *s, struct page *page)
        VM_BUG_ON(!irqs_disabled());
 
        if (!PageSlab(page)) {
-               slab_err(s, page, "Not a valid slab page flags=%lx "
-                       "mapping=0x%p count=%d", page->flags, page->mapping,
-                       page_count(page));
+               slab_err(s, page, "Not a valid slab page");
                return 0;
        }
        if (page->offset * sizeof(void *) != s->offset) {
-               slab_err(s, page, "Corrupted offset %lu flags=0x%lx "
-                       "mapping=0x%p count=%d",
-                       (unsigned long)(page->offset * sizeof(void *)),
-                       page->flags,
-                       page->mapping,
-                       page_count(page));
+               slab_err(s, page, "Corrupted offset %lu",
+                       (unsigned long)(page->offset * sizeof(void *)));
                return 0;
        }
        if (page->inuse > s->objects) {
-               slab_err(s, page, "inuse %u > max %u @0x%p flags=%lx "
-                       "mapping=0x%p count=%d",
-                       s->name, page->inuse, s->objects, page->flags,
-                       page->mapping, page_count(page));
+               slab_err(s, page, "inuse %u > max %u",
+                       s->name, page->inuse, s->objects);
                return 0;
        }
        /* Slab_pad_check fixes things up after itself */
@@ -719,13 +762,10 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
                                set_freepointer(s, object, NULL);
                                break;
                        } else {
-                               slab_err(s, page, "Freepointer 0x%p corrupt",
-                                                                       fp);
+                               slab_err(s, page, "Freepointer corrupt");
                                page->freelist = NULL;
                                page->inuse = s->objects;
-                               printk(KERN_ERR "@@@ SLUB %s: Freelist "
-                                       "cleared. Slab 0x%p\n",
-                                       s->name, page);
+                               slab_fix(s, "Freelist cleared");
                                return 0;
                        }
                        break;
@@ -737,11 +777,9 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
 
        if (page->inuse != s->objects - nr) {
                slab_err(s, page, "Wrong object count. Counter is %d but "
-                       "counted were %d", s, page, page->inuse,
-                                                       s->objects - nr);
+                       "counted were %d", page->inuse, s->objects - nr);
                page->inuse = s->objects - nr;
-               printk(KERN_ERR "@@@ SLUB %s: Object count adjusted. "
-                       "Slab @0x%p\n", s->name, page);
+               slab_fix(s, "Object count adjusted.");
        }
        return search == NULL;
 }
@@ -803,7 +841,7 @@ static int alloc_debug_processing(struct kmem_cache *s, struct page *page,
                goto bad;
 
        if (object && !on_freelist(s, page, object)) {
-               slab_err(s, page, "Object 0x%p already allocated", object);
+               object_err(s, page, object, "Object already allocated");
                goto bad;
        }
 
@@ -829,8 +867,7 @@ bad:
                 * to avoid issues in the future. Marking all objects
                 * as used avoids touching the remaining objects.
                 */
-               printk(KERN_ERR "@@@ SLUB: %s slab 0x%p. Marking all objects used.\n",
-                       s->name, page);
+               slab_fix(s, "Marking all objects used");
                page->inuse = s->objects;
                page->freelist = NULL;
                /* Fix up fields that may be corrupted */
@@ -851,7 +888,7 @@ static int free_debug_processing(struct kmem_cache *s, struct page *page,
        }
 
        if (on_freelist(s, page, object)) {
-               slab_err(s, page, "Object 0x%p already free", object);
+               object_err(s, page, object, "Object already free");
                goto fail;
        }
 
@@ -870,8 +907,8 @@ static int free_debug_processing(struct kmem_cache *s, struct page *page,
                        dump_stack();
                }
                else
-                       slab_err(s, page, "object at 0x%p belongs "
-                               "to slab %s", object, page->slab->name);
+                       object_err(s, page, object,
+                                       "page slab pointer corrupt.");
                goto fail;
        }
 
@@ -885,8 +922,7 @@ static int free_debug_processing(struct kmem_cache *s, struct page *page,
        return 1;
 
 fail:
-       printk(KERN_ERR "@@@ SLUB: %s slab 0x%p object at 0x%p not freed.\n",
-               s->name, page, object);
+       slab_fix(s, "Object at 0x%p not freed", object);
        return 0;
 }
 
@@ -1705,8 +1741,17 @@ static inline int slab_order(int size, int min_objects,
 {
        int order;
        int rem;
+       int min_order = slub_min_order;
+
+       /*
+        * If we would create too many object per slab then reduce
+        * the slab order even if it goes below slub_min_order.
+        */
+       while (min_order > 0 &&
+               (PAGE_SIZE << min_order) >= MAX_OBJECTS_PER_SLAB * size)
+                       min_order--;
 
-       for (order = max(slub_min_order,
+       for (order = max(min_order,
                                fls(min_objects * size - 1) - PAGE_SHIFT);
                        order <= max_order; order++) {
 
@@ -1720,6 +1765,9 @@ static inline int slab_order(int size, int min_objects,
                if (rem <= slab_size / fract_leftover)
                        break;
 
+               /* If the next size is too high then exit now */
+               if (slab_size * 2 >= MAX_OBJECTS_PER_SLAB * size)
+                       break;
        }
 
        return order;
@@ -1828,7 +1876,8 @@ static struct kmem_cache_node * __init early_kmem_cache_node_alloc(gfp_t gfpflag
        page->freelist = get_freepointer(kmalloc_caches, n);
        page->inuse++;
        kmalloc_caches->node[node] = n;
-       setup_object_debug(kmalloc_caches, page, n);
+       init_object(kmalloc_caches, n, 1);
+       init_tracking(kmalloc_caches, n);
        init_kmem_cache_node(n);
        atomic_long_inc(&n->nr_slabs);
        add_partial(n, page);
@@ -2006,7 +2055,7 @@ static int calculate_sizes(struct kmem_cache *s)
         * The page->inuse field is only 16 bit wide! So we cannot have
         * more than 64k objects per slab.
         */
-       if (!s->objects || s->objects > 65535)
+       if (!s->objects || s->objects > MAX_OBJECTS_PER_SLAB)
                return 0;
        return 1;
 
@@ -2542,7 +2591,7 @@ static struct kmem_cache *find_mergeable(size_t size,
                size_t align, unsigned long flags,
                void (*ctor)(void *, struct kmem_cache *, unsigned long))
 {
-       struct list_head *h;
+       struct kmem_cache *s;
 
        if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
                return NULL;
@@ -2554,10 +2603,7 @@ static struct kmem_cache *find_mergeable(size_t size,
        align = calculate_alignment(flags, align, size);
        size = ALIGN(size, align);
 
-       list_for_each(h, &slab_caches) {
-               struct kmem_cache *s =
-                       container_of(h, struct kmem_cache, list);
-
+       list_for_each_entry(s, &slab_caches, list) {
                if (slab_unmergeable(s))
                        continue;
 
@@ -2639,33 +2685,6 @@ void *kmem_cache_zalloc(struct kmem_cache *s, gfp_t flags)
 EXPORT_SYMBOL(kmem_cache_zalloc);
 
 #ifdef CONFIG_SMP
-static void for_all_slabs(void (*func)(struct kmem_cache *, int), int cpu)
-{
-       struct list_head *h;
-
-       down_read(&slub_lock);
-       list_for_each(h, &slab_caches) {
-               struct kmem_cache *s =
-                       container_of(h, struct kmem_cache, list);
-
-               func(s, cpu);
-       }
-       up_read(&slub_lock);
-}
-
-/*
- * Version of __flush_cpu_slab for the case that interrupts
- * are enabled.
- */
-static void cpu_slab_flush(struct kmem_cache *s, int cpu)
-{
-       unsigned long flags;
-
-       local_irq_save(flags);
-       __flush_cpu_slab(s, cpu);
-       local_irq_restore(flags);
-}
-
 /*
  * Use the cpu notifier to insure that the cpu slabs are flushed when
  * necessary.
@@ -2674,13 +2693,21 @@ static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
                unsigned long action, void *hcpu)
 {
        long cpu = (long)hcpu;
+       struct kmem_cache *s;
+       unsigned long flags;
 
        switch (action) {
        case CPU_UP_CANCELED:
        case CPU_UP_CANCELED_FROZEN:
        case CPU_DEAD:
        case CPU_DEAD_FROZEN:
-               for_all_slabs(cpu_slab_flush, cpu);
+               down_read(&slub_lock);
+               list_for_each_entry(s, &slab_caches, list) {
+                       local_irq_save(flags);
+                       __flush_cpu_slab(s, cpu);
+                       local_irq_restore(flags);
+               }
+               up_read(&slub_lock);
                break;
        default:
                break;
@@ -2893,18 +2920,14 @@ static void free_loc_track(struct loc_track *t)
                        get_order(sizeof(struct location) * t->max));
 }
 
-static int alloc_loc_track(struct loc_track *t, unsigned long max)
+static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
 {
        struct location *l;
        int order;
 
-       if (!max)
-               max = PAGE_SIZE / sizeof(struct location);
-
        order = get_order(sizeof(struct location) * max);
 
-       l = (void *)__get_free_pages(GFP_ATOMIC, order);
-
+       l = (void *)__get_free_pages(flags, order);
        if (!l)
                return 0;
 
@@ -2970,7 +2993,7 @@ static int add_location(struct loc_track *t, struct kmem_cache *s,
        /*
         * Not found. Insert new tracking element.
         */
-       if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max))
+       if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
                return 0;
 
        l = t->loc + pos;
@@ -3013,11 +3036,12 @@ static int list_locations(struct kmem_cache *s, char *buf,
 {
        int n = 0;
        unsigned long i;
-       struct loc_track t;
+       struct loc_track t = { 0, 0, NULL };
        int node;
 
-       t.count = 0;
-       t.max = 0;
+       if (!alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
+                       GFP_KERNEL))
+               return sprintf(buf, "Out of memory\n");
 
        /* Push back cpu slabs */
        flush_all(s);
@@ -3705,7 +3729,7 @@ static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
 
 static int __init slab_sysfs_init(void)
 {
-       struct list_head *h;
+       struct kmem_cache *s;
        int err;
 
        err = subsystem_register(&slab_subsys);
@@ -3716,10 +3740,7 @@ static int __init slab_sysfs_init(void)
 
        slab_state = SYSFS;
 
-       list_for_each(h, &slab_caches) {
-               struct kmem_cache *s =
-                       container_of(h, struct kmem_cache, list);
-
+       list_for_each_entry(s, &slab_caches, list) {
                err = sysfs_slab_add(s);
                BUG_ON(err);
        }