#include <linux/nodemask.h>
#include <linux/mm.h>
#include <linux/workqueue.h>
+#include <linux/crc32.h>
#include <asm/sections.h>
#include <asm/processor.h>
#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
#define SECS_FIRST_SCAN 60 /* delay before the first scan */
#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
-#define GRAY_LIST_PASSES 25 /* maximum number of gray list scans */
#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
#define BYTES_PER_POINTER sizeof(void *)
/* scanning area inside a memory block */
struct kmemleak_scan_area {
struct hlist_node node;
- unsigned long offset;
- size_t length;
+ unsigned long start;
+ size_t size;
};
+#define KMEMLEAK_GREY 0
+#define KMEMLEAK_BLACK -1
+
/*
* Structure holding the metadata for each allocated memory block.
* Modifications to such objects should be made while holding the
int min_count;
/* the total number of pointers found pointing to this object */
int count;
+ /* checksum for detecting modified objects */
+ u32 checksum;
/* memory ranges to be scanned inside an object (empty for all) */
struct hlist_head area_list;
unsigned long trace[MAX_TRACE];
#define OBJECT_REPORTED (1 << 1)
/* flag set to not scan the object */
#define OBJECT_NO_SCAN (1 << 2)
-/* flag set on newly allocated objects */
-#define OBJECT_NEW (1 << 3)
/* number of bytes to print per line; must be 16 or 32 */
#define HEX_ROW_SIZE 16
const void *ptr; /* allocated/freed memory block */
size_t size; /* memory block size */
int min_count; /* minimum reference count */
- unsigned long offset; /* scan area offset */
- size_t length; /* scan area length */
unsigned long trace[MAX_TRACE]; /* stack trace */
unsigned int trace_len; /* stack trace length */
};
*/
static bool color_white(const struct kmemleak_object *object)
{
- return object->count != -1 && object->count < object->min_count;
+ return object->count != KMEMLEAK_BLACK &&
+ object->count < object->min_count;
}
static bool color_gray(const struct kmemleak_object *object)
{
- return object->min_count != -1 && object->count >= object->min_count;
-}
-
-static bool color_black(const struct kmemleak_object *object)
-{
- return object->min_count == -1;
+ return object->min_count != KMEMLEAK_BLACK &&
+ object->count >= object->min_count;
}
/*
*/
static bool unreferenced_object(struct kmemleak_object *object)
{
- return (object->flags & OBJECT_ALLOCATED) && color_white(object) &&
+ return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
time_before_eq(object->jiffies + jiffies_min_age,
jiffies_last_scan);
}
struct kmemleak_object *object)
{
int i;
+ unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
object->pointer, object->size);
- seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n",
- object->comm, object->pid, object->jiffies);
+ seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
+ object->comm, object->pid, object->jiffies,
+ msecs_age / 1000, msecs_age % 1000);
hex_dump_object(seq, object);
seq_printf(seq, " backtrace:\n");
pr_notice(" min_count = %d\n", object->min_count);
pr_notice(" count = %d\n", object->count);
pr_notice(" flags = 0x%lx\n", object->flags);
+ pr_notice(" checksum = %d\n", object->checksum);
pr_notice(" backtrace:\n");
print_stack_trace(&trace, 4);
}
INIT_HLIST_HEAD(&object->area_list);
spin_lock_init(&object->lock);
atomic_set(&object->use_count, 1);
- object->flags = OBJECT_ALLOCATED | OBJECT_NEW;
+ object->flags = OBJECT_ALLOCATED;
object->pointer = ptr;
object->size = size;
object->min_count = min_count;
- object->count = -1; /* no color initially */
+ object->count = 0; /* white color initially */
object->jiffies = jiffies;
+ object->checksum = 0;
/* task information */
if (in_irq()) {
object->tree_node.last = ptr + size - 1;
write_lock_irqsave(&kmemleak_lock, flags);
+
min_addr = min(min_addr, ptr);
max_addr = max(max_addr, ptr + size);
node = prio_tree_insert(&object_tree_root, &object->tree_node);
* random memory blocks.
*/
if (node != &object->tree_node) {
- unsigned long flags;
-
kmemleak_stop("Cannot insert 0x%lx into the object search tree "
"(already existing)\n", ptr);
object = lookup_object(ptr, 1);
- spin_lock_irqsave(&object->lock, flags);
+ spin_lock(&object->lock);
dump_object_info(object);
- spin_unlock_irqrestore(&object->lock, flags);
+ spin_unlock(&object->lock);
goto out;
}
put_object(object);
}
-/*
- * Make a object permanently as gray-colored so that it can no longer be
- * reported as a leak. This is used in general to mark a false positive.
- */
-static void make_gray_object(unsigned long ptr)
+
+static void __paint_it(struct kmemleak_object *object, int color)
+{
+ object->min_count = color;
+ if (color == KMEMLEAK_BLACK)
+ object->flags |= OBJECT_NO_SCAN;
+}
+
+static void paint_it(struct kmemleak_object *object, int color)
{
unsigned long flags;
+
+ spin_lock_irqsave(&object->lock, flags);
+ __paint_it(object, color);
+ spin_unlock_irqrestore(&object->lock, flags);
+}
+
+static void paint_ptr(unsigned long ptr, int color)
+{
struct kmemleak_object *object;
object = find_and_get_object(ptr, 0);
if (!object) {
- kmemleak_warn("Graying unknown object at 0x%08lx\n", ptr);
+ kmemleak_warn("Trying to color unknown object "
+ "at 0x%08lx as %s\n", ptr,
+ (color == KMEMLEAK_GREY) ? "Grey" :
+ (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
return;
}
-
- spin_lock_irqsave(&object->lock, flags);
- object->min_count = 0;
- spin_unlock_irqrestore(&object->lock, flags);
+ paint_it(object, color);
put_object(object);
}
/*
+ * Make a object permanently as gray-colored so that it can no longer be
+ * reported as a leak. This is used in general to mark a false positive.
+ */
+static void make_gray_object(unsigned long ptr)
+{
+ paint_ptr(ptr, KMEMLEAK_GREY);
+}
+
+/*
* Mark the object as black-colored so that it is ignored from scans and
* reporting.
*/
static void make_black_object(unsigned long ptr)
{
- unsigned long flags;
- struct kmemleak_object *object;
-
- object = find_and_get_object(ptr, 0);
- if (!object) {
- kmemleak_warn("Blacking unknown object at 0x%08lx\n", ptr);
- return;
- }
-
- spin_lock_irqsave(&object->lock, flags);
- object->min_count = -1;
- object->flags |= OBJECT_NO_SCAN;
- spin_unlock_irqrestore(&object->lock, flags);
- put_object(object);
+ paint_ptr(ptr, KMEMLEAK_BLACK);
}
/*
* Add a scanning area to the object. If at least one such area is added,
* kmemleak will only scan these ranges rather than the whole memory block.
*/
-static void add_scan_area(unsigned long ptr, unsigned long offset,
- size_t length, gfp_t gfp)
+static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
{
unsigned long flags;
struct kmemleak_object *object;
struct kmemleak_scan_area *area;
- object = find_and_get_object(ptr, 0);
+ object = find_and_get_object(ptr, 1);
if (!object) {
kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
ptr);
}
spin_lock_irqsave(&object->lock, flags);
- if (offset + length > object->size) {
+ if (ptr + size > object->pointer + object->size) {
kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
dump_object_info(object);
kmem_cache_free(scan_area_cache, area);
}
INIT_HLIST_NODE(&area->node);
- area->offset = offset;
- area->length = length;
+ area->start = ptr;
+ area->size = size;
hlist_add_head(&area->node, &object->area_list);
out_unlock:
* processed later once kmemleak is fully initialized.
*/
static void __init log_early(int op_type, const void *ptr, size_t size,
- int min_count, unsigned long offset, size_t length)
+ int min_count)
{
unsigned long flags;
struct early_log *log;
if (crt_early_log >= ARRAY_SIZE(early_log)) {
- pr_warning("Early log buffer exceeded\n");
+ pr_warning("Early log buffer exceeded, "
+ "please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n");
kmemleak_disable();
return;
}
log->ptr = ptr;
log->size = size;
log->min_count = min_count;
- log->offset = offset;
- log->length = length;
if (op_type == KMEMLEAK_ALLOC)
log->trace_len = __save_stack_trace(log->trace);
crt_early_log++;
*/
rcu_read_lock();
object = create_object((unsigned long)log->ptr, log->size,
- log->min_count, GFP_KERNEL);
+ log->min_count, GFP_ATOMIC);
+ if (!object)
+ goto out;
spin_lock_irqsave(&object->lock, flags);
for (i = 0; i < log->trace_len; i++)
object->trace[i] = log->trace[i];
object->trace_len = log->trace_len;
spin_unlock_irqrestore(&object->lock, flags);
+out:
rcu_read_unlock();
}
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
create_object((unsigned long)ptr, size, min_count, gfp);
else if (atomic_read(&kmemleak_early_log))
- log_early(KMEMLEAK_ALLOC, ptr, size, min_count, 0, 0);
+ log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
}
EXPORT_SYMBOL_GPL(kmemleak_alloc);
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
delete_object_full((unsigned long)ptr);
else if (atomic_read(&kmemleak_early_log))
- log_early(KMEMLEAK_FREE, ptr, 0, 0, 0, 0);
+ log_early(KMEMLEAK_FREE, ptr, 0, 0);
}
EXPORT_SYMBOL_GPL(kmemleak_free);
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
delete_object_part((unsigned long)ptr, size);
else if (atomic_read(&kmemleak_early_log))
- log_early(KMEMLEAK_FREE_PART, ptr, size, 0, 0, 0);
+ log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
}
EXPORT_SYMBOL_GPL(kmemleak_free_part);
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
make_gray_object((unsigned long)ptr);
else if (atomic_read(&kmemleak_early_log))
- log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0, 0, 0);
+ log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
}
EXPORT_SYMBOL(kmemleak_not_leak);
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
make_black_object((unsigned long)ptr);
else if (atomic_read(&kmemleak_early_log))
- log_early(KMEMLEAK_IGNORE, ptr, 0, 0, 0, 0);
+ log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
}
EXPORT_SYMBOL(kmemleak_ignore);
/*
* Limit the range to be scanned in an allocated memory block.
*/
-void __ref kmemleak_scan_area(const void *ptr, unsigned long offset,
- size_t length, gfp_t gfp)
+void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
- add_scan_area((unsigned long)ptr, offset, length, gfp);
+ add_scan_area((unsigned long)ptr, size, gfp);
else if (atomic_read(&kmemleak_early_log))
- log_early(KMEMLEAK_SCAN_AREA, ptr, 0, 0, offset, length);
+ log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
}
EXPORT_SYMBOL(kmemleak_scan_area);
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
object_no_scan((unsigned long)ptr);
else if (atomic_read(&kmemleak_early_log))
- log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0, 0, 0);
+ log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
}
EXPORT_SYMBOL(kmemleak_no_scan);
/*
+ * Update an object's checksum and return true if it was modified.
+ */
+static bool update_checksum(struct kmemleak_object *object)
+{
+ u32 old_csum = object->checksum;
+
+ if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
+ return false;
+
+ object->checksum = crc32(0, (void *)object->pointer, object->size);
+ return object->checksum != old_csum;
+}
+
+/*
* Memory scanning is a long process and it needs to be interruptable. This
* function checks whether such interrupt condition occured.
*/
* added to the gray_list.
*/
object->count++;
- if (color_gray(object))
+ if (color_gray(object)) {
list_add_tail(&object->gray_list, &gray_list);
- else
- put_object(object);
+ spin_unlock_irqrestore(&object->lock, flags);
+ continue;
+ }
+
spin_unlock_irqrestore(&object->lock, flags);
+ put_object(object);
}
}
unsigned long flags;
/*
- * Once the object->lock is aquired, the corresponding memory block
- * cannot be freed (the same lock is aquired in delete_object).
+ * Once the object->lock is acquired, the corresponding memory block
+ * cannot be freed (the same lock is acquired in delete_object).
*/
spin_lock_irqsave(&object->lock, flags);
if (object->flags & OBJECT_NO_SCAN)
}
} else
hlist_for_each_entry(area, elem, &object->area_list, node)
- scan_block((void *)(object->pointer + area->offset),
- (void *)(object->pointer + area->offset
- + area->length), object, 0);
+ scan_block((void *)area->start,
+ (void *)(area->start + area->size),
+ object, 0);
out:
spin_unlock_irqrestore(&object->lock, flags);
}
/*
+ * Scan the objects already referenced (gray objects). More objects will be
+ * referenced and, if there are no memory leaks, all the objects are scanned.
+ */
+static void scan_gray_list(void)
+{
+ struct kmemleak_object *object, *tmp;
+
+ /*
+ * The list traversal is safe for both tail additions and removals
+ * from inside the loop. The kmemleak objects cannot be freed from
+ * outside the loop because their use_count was incremented.
+ */
+ object = list_entry(gray_list.next, typeof(*object), gray_list);
+ while (&object->gray_list != &gray_list) {
+ cond_resched();
+
+ /* may add new objects to the list */
+ if (!scan_should_stop())
+ scan_object(object);
+
+ tmp = list_entry(object->gray_list.next, typeof(*object),
+ gray_list);
+
+ /* remove the object from the list and release it */
+ list_del(&object->gray_list);
+ put_object(object);
+
+ object = tmp;
+ }
+ WARN_ON(!list_empty(&gray_list));
+}
+
+/*
* Scan data sections and all the referenced memory blocks allocated via the
* kernel's standard allocators. This function must be called with the
* scan_mutex held.
static void kmemleak_scan(void)
{
unsigned long flags;
- struct kmemleak_object *object, *tmp;
+ struct kmemleak_object *object;
int i;
int new_leaks = 0;
- int gray_list_pass = 0;
jiffies_last_scan = jiffies;
#endif
/* reset the reference count (whiten the object) */
object->count = 0;
- object->flags &= ~OBJECT_NEW;
if (color_gray(object) && get_object(object))
list_add_tail(&object->gray_list, &gray_list);
/*
* Scan the objects already referenced from the sections scanned
- * above. More objects will be referenced and, if there are no memory
- * leaks, all the objects will be scanned. The list traversal is safe
- * for both tail additions and removals from inside the loop. The
- * kmemleak objects cannot be freed from outside the loop because their
- * use_count was increased.
+ * above.
*/
-repeat:
- object = list_entry(gray_list.next, typeof(*object), gray_list);
- while (&object->gray_list != &gray_list) {
- cond_resched();
-
- /* may add new objects to the list */
- if (!scan_should_stop())
- scan_object(object);
-
- tmp = list_entry(object->gray_list.next, typeof(*object),
- gray_list);
-
- /* remove the object from the list and release it */
- list_del(&object->gray_list);
- put_object(object);
-
- object = tmp;
- }
-
- if (scan_should_stop() || ++gray_list_pass >= GRAY_LIST_PASSES)
- goto scan_end;
+ scan_gray_list();
/*
- * Check for new objects allocated during this scanning and add them
- * to the gray list.
+ * Check for new or unreferenced objects modified since the previous
+ * scan and color them gray until the next scan.
*/
rcu_read_lock();
list_for_each_entry_rcu(object, &object_list, object_list) {
spin_lock_irqsave(&object->lock, flags);
- if ((object->flags & OBJECT_NEW) && !color_black(object) &&
- get_object(object)) {
- object->flags &= ~OBJECT_NEW;
+ if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
+ && update_checksum(object) && get_object(object)) {
+ /* color it gray temporarily */
+ object->count = object->min_count;
list_add_tail(&object->gray_list, &gray_list);
}
spin_unlock_irqrestore(&object->lock, flags);
}
rcu_read_unlock();
- if (!list_empty(&gray_list))
- goto repeat;
-
-scan_end:
- WARN_ON(!list_empty(&gray_list));
+ /*
+ * Re-scan the gray list for modified unreferenced objects.
+ */
+ scan_gray_list();
/*
- * If scanning was stopped or new objects were being allocated at a
- * higher rate than gray list scanning, do not report any new
- * unreferenced objects.
+ * If scanning was stopped do not report any new unreferenced objects.
*/
- if (scan_should_stop() || gray_list_pass >= GRAY_LIST_PASSES)
+ if (scan_should_stop())
return;
/*
* Start the automatic memory scanning thread. This function must be called
* with the scan_mutex held.
*/
-void start_scan_thread(void)
+static void start_scan_thread(void)
{
if (scan_thread)
return;
* Stop the automatic memory scanning thread. This function must be called
* with the scan_mutex held.
*/
-void stop_scan_thread(void)
+static void stop_scan_thread(void)
{
if (scan_thread) {
kthread_stop(scan_thread);
spin_lock_irqsave(&object->lock, flags);
if ((object->flags & OBJECT_REPORTED) &&
unreferenced_object(object))
- object->min_count = 0;
+ __paint_it(object, KMEMLEAK_GREY);
spin_unlock_irqrestore(&object->lock, flags);
}
rcu_read_unlock();
kmemleak_ignore(log->ptr);
break;
case KMEMLEAK_SCAN_AREA:
- kmemleak_scan_area(log->ptr, log->offset, log->length,
- GFP_KERNEL);
+ kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
break;
case KMEMLEAK_NO_SCAN:
kmemleak_no_scan(log->ptr);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff