#include <linux/sched.h>
#include <linux/jiffies.h>
#include <linux/delay.h>
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/kthread.h>
#include <linux/prio_tree.h>
-#include <linux/gfp.h>
#include <linux/fs.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/nodemask.h>
#include <linux/mm.h>
#include <linux/workqueue.h>
+#include <linux/crc32.h>
#include <asm/sections.h>
#include <asm/processor.h>
-#include <asm/atomic.h>
+#include <linux/atomic.h>
#include <linux/kmemcheck.h>
#include <linux/kmemleak.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 *)
/* GFP bitmask for kmemleak internal allocations */
-#define GFP_KMEMLEAK_MASK (GFP_KERNEL | GFP_ATOMIC)
+#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
+ __GFP_NORETRY | __GFP_NOMEMALLOC | \
+ __GFP_NOWARN)
/* 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
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
static int kmemleak_stack_scan = 1;
/* protects the memory scanning, parameters and debug/kmemleak file access */
static DEFINE_MUTEX(scan_mutex);
+/* setting kmemleak=on, will set this var, skipping the disable */
+static int kmemleak_skip_disable;
+
/*
* Early object allocation/freeing logging. Kmemleak is initialized after the
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 */
};
} while (0)
/*
- * Macro invoked when a serious kmemleak condition occured and cannot be
+ * Macro invoked when a serious kmemleak condition occurred and cannot be
* recovered from. Kmemleak will be disabled and further allocation/freeing
* tracing no longer available.
*/
object->count >= object->min_count;
}
-static bool color_black(const struct kmemleak_object *object)
-{
- return object->min_count == KMEMLEAK_BLACK;
-}
-
/*
* Objects are considered unreferenced only if their color is white, they have
* not be deleted and have a minimum age to avoid false positives caused by
*/
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);
}
object = prio_tree_entry(node, struct kmemleak_object,
tree_node);
if (!alias && object->pointer != ptr) {
- kmemleak_warn("Found object by alias");
+ pr_warning("Found object by alias at 0x%08lx\n", ptr);
+ dump_stack();
+ dump_object_info(object);
object = NULL;
}
} else
struct kmemleak_object *object;
struct prio_tree_node *node;
- object = kmem_cache_alloc(object_cache, gfp & GFP_KMEMLEAK_MASK);
+ object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
if (!object) {
- kmemleak_stop("Cannot allocate a kmemleak_object structure\n");
+ pr_warning("Cannot allocate a kmemleak_object structure\n");
+ kmemleak_disable();
return NULL;
}
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()) {
}
/*
- * Make a object permanently as gray-colored so that it can no longer be
+ * Mark an 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)
* 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);
return;
}
- area = kmem_cache_alloc(scan_area_cache, gfp & GFP_KMEMLEAK_MASK);
+ area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
if (!area) {
- kmemleak_warn("Cannot allocate a scan area\n");
+ pr_warning("Cannot allocate a scan area\n");
goto out;
}
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;
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_unlock();
}
-/*
- * Memory allocation function callback. This function is called from the
- * kernel allocators when a new block is allocated (kmem_cache_alloc, kmalloc,
- * vmalloc etc.).
+/**
+ * kmemleak_alloc - register a newly allocated object
+ * @ptr: pointer to beginning of the object
+ * @size: size of the object
+ * @min_count: minimum number of references to this object. If during memory
+ * scanning a number of references less than @min_count is found,
+ * the object is reported as a memory leak. If @min_count is 0,
+ * the object is never reported as a leak. If @min_count is -1,
+ * the object is ignored (not scanned and not reported as a leak)
+ * @gfp: kmalloc() flags used for kmemleak internal memory allocations
+ *
+ * This function is called from the kernel allocators when a new object
+ * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.).
*/
void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
gfp_t gfp)
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);
-/*
- * Memory freeing function callback. This function is called from the kernel
- * allocators when a block is freed (kmem_cache_free, kfree, vfree etc.).
+/**
+ * kmemleak_free - unregister a previously registered object
+ * @ptr: pointer to beginning of the object
+ *
+ * This function is called from the kernel allocators when an object (memory
+ * block) is freed (kmem_cache_free, kfree, vfree etc.).
*/
void __ref kmemleak_free(const void *ptr)
{
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);
-/*
- * Partial memory freeing function callback. This function is usually called
- * from bootmem allocator when (part of) a memory block is freed.
+/**
+ * kmemleak_free_part - partially unregister a previously registered object
+ * @ptr: pointer to the beginning or inside the object. This also
+ * represents the start of the range to be freed
+ * @size: size to be unregistered
+ *
+ * This function is called when only a part of a memory block is freed
+ * (usually from the bootmem allocator).
*/
void __ref kmemleak_free_part(const void *ptr, size_t size)
{
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);
-/*
- * Mark an already allocated memory block as a false positive. This will cause
- * the block to no longer be reported as leak and always be scanned.
+/**
+ * kmemleak_not_leak - mark an allocated object as false positive
+ * @ptr: pointer to beginning of the object
+ *
+ * Calling this function on an object will cause the memory block to no longer
+ * be reported as leak and always be scanned.
*/
void __ref kmemleak_not_leak(const void *ptr)
{
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);
-/*
- * Ignore a memory block. This is usually done when it is known that the
- * corresponding block is not a leak and does not contain any references to
- * other allocated memory blocks.
+/**
+ * kmemleak_ignore - ignore an allocated object
+ * @ptr: pointer to beginning of the object
+ *
+ * Calling this function on an object will cause the memory block to be
+ * ignored (not scanned and not reported as a leak). This is usually done when
+ * it is known that the corresponding block is not a leak and does not contain
+ * any references to other allocated memory blocks.
*/
void __ref kmemleak_ignore(const void *ptr)
{
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.
+/**
+ * kmemleak_scan_area - limit the range to be scanned in an allocated object
+ * @ptr: pointer to beginning or inside the object. This also
+ * represents the start of the scan area
+ * @size: size of the scan area
+ * @gfp: kmalloc() flags used for kmemleak internal memory allocations
+ *
+ * This function is used when it is known that only certain parts of an object
+ * contain references to other objects. Kmemleak will only scan these areas
+ * reducing the number false negatives.
*/
-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);
-/*
- * Inform kmemleak not to scan the given memory block.
+/**
+ * kmemleak_no_scan - do not scan an allocated object
+ * @ptr: pointer to beginning of the object
+ *
+ * This function notifies kmemleak not to scan the given memory block. Useful
+ * in situations where it is known that the given object does not contain any
+ * references to other objects. Kmemleak will not scan such objects reducing
+ * the number of false negatives.
*/
void __ref kmemleak_no_scan(const void *ptr)
{
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.
+ * function checks whether such interrupt condition occurred.
*/
static int scan_should_stop(void)
{
* 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;
/*
++(*pos);
list_for_each_continue_rcu(n, &object_list) {
- next_obj = list_entry(n, struct kmemleak_object, object_list);
- if (get_object(next_obj))
+ struct kmemleak_object *obj =
+ list_entry(n, struct kmemleak_object, object_list);
+ if (get_object(obj)) {
+ next_obj = obj;
break;
+ }
}
put_object(prev_obj);
return -EINVAL;
if (strcmp(str, "off") == 0)
kmemleak_disable();
- else if (strcmp(str, "on") != 0)
+ else if (strcmp(str, "on") == 0)
+ kmemleak_skip_disable = 1;
+ else
return -EINVAL;
return 0;
}
int i;
unsigned long flags;
+#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
+ if (!kmemleak_skip_disable) {
+ kmemleak_disable();
+ return;
+ }
+#endif
+
jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
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);
if (atomic_read(&kmemleak_error)) {
/*
- * Some error occured and kmemleak was disabled. There is a
+ * Some error occurred and kmemleak was disabled. There is a
* small chance that kmemleak_disable() was called immediately
* after setting kmemleak_initialized and we may end up with
* two clean-up threads but serialized by scan_mutex.
projects / linux-flexiantxendom0.git / blobdiff