1 files changed, 103 insertions, 2 deletions

diff --git a/mm/slub.c b/mm/slub.c
index 35f351f26193..ba83f3fd0757 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -27,6 +27,7 @@
 #include <linux/memory.h>
 #include <linux/math64.h>
 #include <linux/fault-inject.h>
+#include <linux/stacktrace.h>
 
 #include <trace/events/kmem.h>
 
@@ -191,8 +192,12 @@ static LIST_HEAD(slab_caches);
 /*
  * Tracking user of a slab.
  */
+#define TRACK_ADDRS_COUNT 16
 struct track {
 	unsigned long addr;	/* Called from address */
+#ifdef CONFIG_STACKTRACE
+	unsigned long addrs[TRACK_ADDRS_COUNT];	/* Called from address */
+#endif
 	int cpu;		/* Was running on cpu */
 	int pid;		/* Pid context */
 	unsigned long when;	/* When did the operation occur */
@@ -420,6 +425,24 @@ static void set_track(struct kmem_cache *s, void *object,
 	struct track *p = get_track(s, object, alloc);
 
 	if (addr) {
+#ifdef CONFIG_STACKTRACE
+		struct stack_trace trace;
+		int i;
+
+		trace.nr_entries = 0;
+		trace.max_entries = TRACK_ADDRS_COUNT;
+		trace.entries = p->addrs;
+		trace.skip = 3;
+		save_stack_trace(&trace);
+
+		/* See rant in lockdep.c */
+		if (trace.nr_entries != 0 &&
+		    trace.entries[trace.nr_entries - 1] == ULONG_MAX)
+			trace.nr_entries--;
+
+		for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
+			p->addrs[i] = 0;
+#endif
 		p->addr = addr;
 		p->cpu = smp_processor_id();
 		p->pid = current->pid;
@@ -444,6 +467,16 @@ static void print_track(const char *s, struct track *t)
 
 	printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
 		s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
+#ifdef CONFIG_STACKTRACE
+	{
+		int i;
+		for (i = 0; i < TRACK_ADDRS_COUNT; i++)
+			if (t->addrs[i])
+				printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
+			else
+				break;
+	}
+#endif
 }
 
 static void print_tracking(struct kmem_cache *s, void *object)
@@ -557,10 +590,10 @@ static void init_object(struct kmem_cache *s, void *object, u8 val)
 		memset(p + s->objsize, val, s->inuse - s->objsize);
 }
 
-static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
+static u8 *check_bytes8(u8 *start, u8 value, unsigned int bytes)
 {
 	while (bytes) {
-		if (*start != (u8)value)
+		if (*start != value)
 			return start;
 		start++;
 		bytes--;
@@ -568,6 +601,38 @@ static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
 	return NULL;
 }
 
+static u8 *check_bytes(u8 *start, u8 value, unsigned int bytes)
+{
+	u64 value64;
+	unsigned int words, prefix;
+
+	if (bytes <= 16)
+		return check_bytes8(start, value, bytes);
+
+	value64 = value | value << 8 | value << 16 | value << 24;
+	value64 = value64 | value64 << 32;
+	prefix = 8 - ((unsigned long)start) % 8;
+
+	if (prefix) {
+		u8 *r = check_bytes8(start, value, prefix);
+		if (r)
+			return r;
+		start += prefix;
+		bytes -= prefix;
+	}
+
+	words = bytes / 8;
+
+	while (words) {
+		if (*(u64 *)start != value64)
+			return check_bytes8(start, value, 8);
+		start += 8;
+		words--;
+	}
+
+	return check_bytes8(start, value, bytes % 8);
+}
+
 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
 						void *from, void *to)
 {
@@ -2928,6 +2993,42 @@ size_t ksize(const void *object)
 }
 EXPORT_SYMBOL(ksize);
 
+#ifdef CONFIG_SLUB_DEBUG
+bool verify_mem_not_deleted(const void *x)
+{
+	struct page *page;
+	void *object = (void *)x;
+	unsigned long flags;
+	bool rv;
+
+	if (unlikely(ZERO_OR_NULL_PTR(x)))
+		return false;
+
+	local_irq_save(flags);
+
+	page = virt_to_head_page(x);
+	if (unlikely(!PageSlab(page))) {
+		/* maybe it was from stack? */
+		rv = true;
+		goto out_unlock;
+	}
+
+	slab_lock(page);
+	if (on_freelist(page->slab, page, object)) {
+		object_err(page->slab, page, object, "Object is on free-list");
+		rv = false;
+	} else {
+		rv = true;
+	}
+	slab_unlock(page);
+
+out_unlock:
+	local_irq_restore(flags);
+	return rv;
+}
+EXPORT_SYMBOL(verify_mem_not_deleted);
+#endif
+
 void kfree(const void *x)
 {
 	struct page *page;