4 * Copyright (C) 2008 ARM Limited
5 * Written by Catalin Marinas <catalin.marinas@arm.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 * For more information on the algorithm and kmemleak usage, please see
22 * Documentation/kmemleak.txt.
27 * The following locks and mutexes are used by kmemleak:
29 * - kmemleak_lock (rwlock): protects the object_list modifications and
30 * accesses to the object_tree_root. The object_list is the main list
31 * holding the metadata (struct kmemleak_object) for the allocated memory
32 * blocks. The object_tree_root is a priority search tree used to look-up
33 * metadata based on a pointer to the corresponding memory block. The
34 * kmemleak_object structures are added to the object_list and
35 * object_tree_root in the create_object() function called from the
36 * kmemleak_alloc() callback and removed in delete_object() called from the
37 * kmemleak_free() callback
38 * - kmemleak_object.lock (spinlock): protects a kmemleak_object. Accesses to
39 * the metadata (e.g. count) are protected by this lock. Note that some
40 * members of this structure may be protected by other means (atomic or
41 * kmemleak_lock). This lock is also held when scanning the corresponding
42 * memory block to avoid the kernel freeing it via the kmemleak_free()
43 * callback. This is less heavyweight than holding a global lock like
44 * kmemleak_lock during scanning
45 * - scan_mutex (mutex): ensures that only one thread may scan the memory for
46 * unreferenced objects at a time. The gray_list contains the objects which
47 * are already referenced or marked as false positives and need to be
48 * scanned. This list is only modified during a scanning episode when the
49 * scan_mutex is held. At the end of a scan, the gray_list is always empty.
50 * Note that the kmemleak_object.use_count is incremented when an object is
51 * added to the gray_list and therefore cannot be freed. This mutex also
52 * prevents multiple users of the "kmemleak" debugfs file together with
53 * modifications to the memory scanning parameters including the scan_thread
56 * The kmemleak_object structures have a use_count incremented or decremented
57 * using the get_object()/put_object() functions. When the use_count becomes
58 * 0, this count can no longer be incremented and put_object() schedules the
59 * kmemleak_object freeing via an RCU callback. All calls to the get_object()
60 * function must be protected by rcu_read_lock() to avoid accessing a freed
64 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
66 #include <linux/init.h>
67 #include <linux/kernel.h>
68 #include <linux/list.h>
69 #include <linux/sched.h>
70 #include <linux/jiffies.h>
71 #include <linux/delay.h>
72 #include <linux/export.h>
73 #include <linux/kthread.h>
74 #include <linux/prio_tree.h>
76 #include <linux/debugfs.h>
77 #include <linux/seq_file.h>
78 #include <linux/cpumask.h>
79 #include <linux/spinlock.h>
80 #include <linux/mutex.h>
81 #include <linux/rcupdate.h>
82 #include <linux/stacktrace.h>
83 #include <linux/cache.h>
84 #include <linux/percpu.h>
85 #include <linux/hardirq.h>
86 #include <linux/mmzone.h>
87 #include <linux/slab.h>
88 #include <linux/thread_info.h>
89 #include <linux/err.h>
90 #include <linux/uaccess.h>
91 #include <linux/string.h>
92 #include <linux/nodemask.h>
94 #include <linux/workqueue.h>
95 #include <linux/crc32.h>
97 #include <asm/sections.h>
98 #include <asm/processor.h>
99 #include <linux/atomic.h>
101 #include <linux/kmemcheck.h>
102 #include <linux/kmemleak.h>
105 * Kmemleak configuration and common defines.
107 #define MAX_TRACE 16 /* stack trace length */
108 #define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
109 #define SECS_FIRST_SCAN 60 /* delay before the first scan */
110 #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
111 #define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
113 #define BYTES_PER_POINTER sizeof(void *)
115 /* GFP bitmask for kmemleak internal allocations */
116 #define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
117 __GFP_NORETRY | __GFP_NOMEMALLOC | \
120 /* scanning area inside a memory block */
121 struct kmemleak_scan_area {
122 struct hlist_node node;
127 #define KMEMLEAK_GREY 0
128 #define KMEMLEAK_BLACK -1
131 * Structure holding the metadata for each allocated memory block.
132 * Modifications to such objects should be made while holding the
133 * object->lock. Insertions or deletions from object_list, gray_list or
134 * tree_node are already protected by the corresponding locks or mutex (see
135 * the notes on locking above). These objects are reference-counted
136 * (use_count) and freed using the RCU mechanism.
138 struct kmemleak_object {
140 unsigned long flags; /* object status flags */
141 struct list_head object_list;
142 struct list_head gray_list;
143 struct prio_tree_node tree_node;
144 struct rcu_head rcu; /* object_list lockless traversal */
145 /* object usage count; object freed when use_count == 0 */
147 unsigned long pointer;
149 /* minimum number of a pointers found before it is considered leak */
151 /* the total number of pointers found pointing to this object */
153 /* checksum for detecting modified objects */
155 /* memory ranges to be scanned inside an object (empty for all) */
156 struct hlist_head area_list;
157 unsigned long trace[MAX_TRACE];
158 unsigned int trace_len;
159 unsigned long jiffies; /* creation timestamp */
160 pid_t pid; /* pid of the current task */
161 char comm[TASK_COMM_LEN]; /* executable name */
164 /* flag representing the memory block allocation status */
165 #define OBJECT_ALLOCATED (1 << 0)
166 /* flag set after the first reporting of an unreference object */
167 #define OBJECT_REPORTED (1 << 1)
168 /* flag set to not scan the object */
169 #define OBJECT_NO_SCAN (1 << 2)
171 /* number of bytes to print per line; must be 16 or 32 */
172 #define HEX_ROW_SIZE 16
173 /* number of bytes to print at a time (1, 2, 4, 8) */
174 #define HEX_GROUP_SIZE 1
175 /* include ASCII after the hex output */
177 /* max number of lines to be printed */
178 #define HEX_MAX_LINES 2
180 /* the list of all allocated objects */
181 static LIST_HEAD(object_list);
182 /* the list of gray-colored objects (see color_gray comment below) */
183 static LIST_HEAD(gray_list);
184 /* prio search tree for object boundaries */
185 static struct prio_tree_root object_tree_root;
186 /* rw_lock protecting the access to object_list and prio_tree_root */
187 static DEFINE_RWLOCK(kmemleak_lock);
189 /* allocation caches for kmemleak internal data */
190 static struct kmem_cache *object_cache;
191 static struct kmem_cache *scan_area_cache;
193 /* set if tracing memory operations is enabled */
194 static atomic_t kmemleak_enabled = ATOMIC_INIT(0);
195 /* set in the late_initcall if there were no errors */
196 static atomic_t kmemleak_initialized = ATOMIC_INIT(0);
197 /* enables or disables early logging of the memory operations */
198 static atomic_t kmemleak_early_log = ATOMIC_INIT(1);
199 /* set if a kmemleak warning was issued */
200 static atomic_t kmemleak_warning = ATOMIC_INIT(0);
201 /* set if a fatal kmemleak error has occurred */
202 static atomic_t kmemleak_error = ATOMIC_INIT(0);
204 /* minimum and maximum address that may be valid pointers */
205 static unsigned long min_addr = ULONG_MAX;
206 static unsigned long max_addr;
208 static struct task_struct *scan_thread;
209 /* used to avoid reporting of recently allocated objects */
210 static unsigned long jiffies_min_age;
211 static unsigned long jiffies_last_scan;
212 /* delay between automatic memory scannings */
213 static signed long jiffies_scan_wait;
214 /* enables or disables the task stacks scanning */
215 static int kmemleak_stack_scan = 1;
216 /* protects the memory scanning, parameters and debug/kmemleak file access */
217 static DEFINE_MUTEX(scan_mutex);
218 /* setting kmemleak=on, will set this var, skipping the disable */
219 static int kmemleak_skip_disable;
223 * Early object allocation/freeing logging. Kmemleak is initialized after the
224 * kernel allocator. However, both the kernel allocator and kmemleak may
225 * allocate memory blocks which need to be tracked. Kmemleak defines an
226 * arbitrary buffer to hold the allocation/freeing information before it is
230 /* kmemleak operation type for early logging */
242 * Structure holding the information passed to kmemleak callbacks during the
246 int op_type; /* kmemleak operation type */
247 const void *ptr; /* allocated/freed memory block */
248 size_t size; /* memory block size */
249 int min_count; /* minimum reference count */
250 unsigned long trace[MAX_TRACE]; /* stack trace */
251 unsigned int trace_len; /* stack trace length */
254 /* early logging buffer and current position */
255 static struct early_log
256 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
257 static int crt_early_log __initdata;
259 static void kmemleak_disable(void);
262 * Print a warning and dump the stack trace.
264 #define kmemleak_warn(x...) do { \
267 atomic_set(&kmemleak_warning, 1); \
271 * Macro invoked when a serious kmemleak condition occurred and cannot be
272 * recovered from. Kmemleak will be disabled and further allocation/freeing
273 * tracing no longer available.
275 #define kmemleak_stop(x...) do { \
277 kmemleak_disable(); \
281 * Printing of the objects hex dump to the seq file. The number of lines to be
282 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
283 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
284 * with the object->lock held.
286 static void hex_dump_object(struct seq_file *seq,
287 struct kmemleak_object *object)
289 const u8 *ptr = (const u8 *)object->pointer;
290 int i, len, remaining;
291 unsigned char linebuf[HEX_ROW_SIZE * 5];
293 /* limit the number of lines to HEX_MAX_LINES */
295 min(object->size, (size_t)(HEX_MAX_LINES * HEX_ROW_SIZE));
297 seq_printf(seq, " hex dump (first %d bytes):\n", len);
298 for (i = 0; i < len; i += HEX_ROW_SIZE) {
299 int linelen = min(remaining, HEX_ROW_SIZE);
301 remaining -= HEX_ROW_SIZE;
302 hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE,
303 HEX_GROUP_SIZE, linebuf, sizeof(linebuf),
305 seq_printf(seq, " %s\n", linebuf);
310 * Object colors, encoded with count and min_count:
311 * - white - orphan object, not enough references to it (count < min_count)
312 * - gray - not orphan, not marked as false positive (min_count == 0) or
313 * sufficient references to it (count >= min_count)
314 * - black - ignore, it doesn't contain references (e.g. text section)
315 * (min_count == -1). No function defined for this color.
316 * Newly created objects don't have any color assigned (object->count == -1)
317 * before the next memory scan when they become white.
319 static bool color_white(const struct kmemleak_object *object)
321 return object->count != KMEMLEAK_BLACK &&
322 object->count < object->min_count;
325 static bool color_gray(const struct kmemleak_object *object)
327 return object->min_count != KMEMLEAK_BLACK &&
328 object->count >= object->min_count;
332 * Objects are considered unreferenced only if their color is white, they have
333 * not be deleted and have a minimum age to avoid false positives caused by
334 * pointers temporarily stored in CPU registers.
336 static bool unreferenced_object(struct kmemleak_object *object)
338 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
339 time_before_eq(object->jiffies + jiffies_min_age,
344 * Printing of the unreferenced objects information to the seq file. The
345 * print_unreferenced function must be called with the object->lock held.
347 static void print_unreferenced(struct seq_file *seq,
348 struct kmemleak_object *object)
351 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
353 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
354 object->pointer, object->size);
355 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
356 object->comm, object->pid, object->jiffies,
357 msecs_age / 1000, msecs_age % 1000);
358 hex_dump_object(seq, object);
359 seq_printf(seq, " backtrace:\n");
361 for (i = 0; i < object->trace_len; i++) {
362 void *ptr = (void *)object->trace[i];
363 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
368 * Print the kmemleak_object information. This function is used mainly for
369 * debugging special cases when kmemleak operations. It must be called with
370 * the object->lock held.
372 static void dump_object_info(struct kmemleak_object *object)
374 struct stack_trace trace;
376 trace.nr_entries = object->trace_len;
377 trace.entries = object->trace;
379 pr_notice("Object 0x%08lx (size %zu):\n",
380 object->tree_node.start, object->size);
381 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
382 object->comm, object->pid, object->jiffies);
383 pr_notice(" min_count = %d\n", object->min_count);
384 pr_notice(" count = %d\n", object->count);
385 pr_notice(" flags = 0x%lx\n", object->flags);
386 pr_notice(" checksum = %d\n", object->checksum);
387 pr_notice(" backtrace:\n");
388 print_stack_trace(&trace, 4);
392 * Look-up a memory block metadata (kmemleak_object) in the priority search
393 * tree based on a pointer value. If alias is 0, only values pointing to the
394 * beginning of the memory block are allowed. The kmemleak_lock must be held
395 * when calling this function.
397 static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
399 struct prio_tree_node *node;
400 struct prio_tree_iter iter;
401 struct kmemleak_object *object;
403 prio_tree_iter_init(&iter, &object_tree_root, ptr, ptr);
404 node = prio_tree_next(&iter);
406 object = prio_tree_entry(node, struct kmemleak_object,
408 if (!alias && object->pointer != ptr) {
409 kmemleak_warn("Found object by alias at 0x%08lx\n",
411 dump_object_info(object);
421 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
422 * that once an object's use_count reached 0, the RCU freeing was already
423 * registered and the object should no longer be used. This function must be
424 * called under the protection of rcu_read_lock().
426 static int get_object(struct kmemleak_object *object)
428 return atomic_inc_not_zero(&object->use_count);
432 * RCU callback to free a kmemleak_object.
434 static void free_object_rcu(struct rcu_head *rcu)
436 struct hlist_node *elem, *tmp;
437 struct kmemleak_scan_area *area;
438 struct kmemleak_object *object =
439 container_of(rcu, struct kmemleak_object, rcu);
442 * Once use_count is 0 (guaranteed by put_object), there is no other
443 * code accessing this object, hence no need for locking.
445 hlist_for_each_entry_safe(area, elem, tmp, &object->area_list, node) {
447 kmem_cache_free(scan_area_cache, area);
449 kmem_cache_free(object_cache, object);
453 * Decrement the object use_count. Once the count is 0, free the object using
454 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
455 * delete_object() path, the delayed RCU freeing ensures that there is no
456 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
459 static void put_object(struct kmemleak_object *object)
461 if (!atomic_dec_and_test(&object->use_count))
464 /* should only get here after delete_object was called */
465 WARN_ON(object->flags & OBJECT_ALLOCATED);
467 call_rcu(&object->rcu, free_object_rcu);
471 * Look up an object in the prio search tree and increase its use_count.
473 static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
476 struct kmemleak_object *object = NULL;
479 read_lock_irqsave(&kmemleak_lock, flags);
480 if (ptr >= min_addr && ptr < max_addr)
481 object = lookup_object(ptr, alias);
482 read_unlock_irqrestore(&kmemleak_lock, flags);
484 /* check whether the object is still available */
485 if (object && !get_object(object))
493 * Save stack trace to the given array of MAX_TRACE size.
495 static int __save_stack_trace(unsigned long *trace)
497 struct stack_trace stack_trace;
499 stack_trace.max_entries = MAX_TRACE;
500 stack_trace.nr_entries = 0;
501 stack_trace.entries = trace;
502 stack_trace.skip = 2;
503 save_stack_trace(&stack_trace);
505 return stack_trace.nr_entries;
509 * Create the metadata (struct kmemleak_object) corresponding to an allocated
510 * memory block and add it to the object_list and object_tree_root.
512 static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
513 int min_count, gfp_t gfp)
516 struct kmemleak_object *object;
517 struct prio_tree_node *node;
519 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
521 pr_warning("Cannot allocate a kmemleak_object structure\n");
526 INIT_LIST_HEAD(&object->object_list);
527 INIT_LIST_HEAD(&object->gray_list);
528 INIT_HLIST_HEAD(&object->area_list);
529 spin_lock_init(&object->lock);
530 atomic_set(&object->use_count, 1);
531 object->flags = OBJECT_ALLOCATED;
532 object->pointer = ptr;
534 object->min_count = min_count;
535 object->count = 0; /* white color initially */
536 object->jiffies = jiffies;
537 object->checksum = 0;
539 /* task information */
542 strncpy(object->comm, "hardirq", sizeof(object->comm));
543 } else if (in_softirq()) {
545 strncpy(object->comm, "softirq", sizeof(object->comm));
547 object->pid = current->pid;
549 * There is a small chance of a race with set_task_comm(),
550 * however using get_task_comm() here may cause locking
551 * dependency issues with current->alloc_lock. In the worst
552 * case, the command line is not correct.
554 strncpy(object->comm, current->comm, sizeof(object->comm));
557 /* kernel backtrace */
558 object->trace_len = __save_stack_trace(object->trace);
560 INIT_PRIO_TREE_NODE(&object->tree_node);
561 object->tree_node.start = ptr;
562 object->tree_node.last = ptr + size - 1;
564 write_lock_irqsave(&kmemleak_lock, flags);
566 min_addr = min(min_addr, ptr);
567 max_addr = max(max_addr, ptr + size);
568 node = prio_tree_insert(&object_tree_root, &object->tree_node);
570 * The code calling the kernel does not yet have the pointer to the
571 * memory block to be able to free it. However, we still hold the
572 * kmemleak_lock here in case parts of the kernel started freeing
573 * random memory blocks.
575 if (node != &object->tree_node) {
576 kmemleak_stop("Cannot insert 0x%lx into the object search tree "
577 "(already existing)\n", ptr);
578 object = lookup_object(ptr, 1);
579 spin_lock(&object->lock);
580 dump_object_info(object);
581 spin_unlock(&object->lock);
585 list_add_tail_rcu(&object->object_list, &object_list);
587 write_unlock_irqrestore(&kmemleak_lock, flags);
592 * Remove the metadata (struct kmemleak_object) for a memory block from the
593 * object_list and object_tree_root and decrement its use_count.
595 static void __delete_object(struct kmemleak_object *object)
599 write_lock_irqsave(&kmemleak_lock, flags);
600 prio_tree_remove(&object_tree_root, &object->tree_node);
601 list_del_rcu(&object->object_list);
602 write_unlock_irqrestore(&kmemleak_lock, flags);
604 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
605 WARN_ON(atomic_read(&object->use_count) < 2);
608 * Locking here also ensures that the corresponding memory block
609 * cannot be freed when it is being scanned.
611 spin_lock_irqsave(&object->lock, flags);
612 object->flags &= ~OBJECT_ALLOCATED;
613 spin_unlock_irqrestore(&object->lock, flags);
618 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
621 static void delete_object_full(unsigned long ptr)
623 struct kmemleak_object *object;
625 object = find_and_get_object(ptr, 0);
628 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
633 __delete_object(object);
638 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
639 * delete it. If the memory block is partially freed, the function may create
640 * additional metadata for the remaining parts of the block.
642 static void delete_object_part(unsigned long ptr, size_t size)
644 struct kmemleak_object *object;
645 unsigned long start, end;
647 object = find_and_get_object(ptr, 1);
650 kmemleak_warn("Partially freeing unknown object at 0x%08lx "
651 "(size %zu)\n", ptr, size);
655 __delete_object(object);
658 * Create one or two objects that may result from the memory block
659 * split. Note that partial freeing is only done by free_bootmem() and
660 * this happens before kmemleak_init() is called. The path below is
661 * only executed during early log recording in kmemleak_init(), so
662 * GFP_KERNEL is enough.
664 start = object->pointer;
665 end = object->pointer + object->size;
667 create_object(start, ptr - start, object->min_count,
669 if (ptr + size < end)
670 create_object(ptr + size, end - ptr - size, object->min_count,
676 static void __paint_it(struct kmemleak_object *object, int color)
678 object->min_count = color;
679 if (color == KMEMLEAK_BLACK)
680 object->flags |= OBJECT_NO_SCAN;
683 static void paint_it(struct kmemleak_object *object, int color)
687 spin_lock_irqsave(&object->lock, flags);
688 __paint_it(object, color);
689 spin_unlock_irqrestore(&object->lock, flags);
692 static void paint_ptr(unsigned long ptr, int color)
694 struct kmemleak_object *object;
696 object = find_and_get_object(ptr, 0);
698 kmemleak_warn("Trying to color unknown object "
699 "at 0x%08lx as %s\n", ptr,
700 (color == KMEMLEAK_GREY) ? "Grey" :
701 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
704 paint_it(object, color);
709 * Mark an object permanently as gray-colored so that it can no longer be
710 * reported as a leak. This is used in general to mark a false positive.
712 static void make_gray_object(unsigned long ptr)
714 paint_ptr(ptr, KMEMLEAK_GREY);
718 * Mark the object as black-colored so that it is ignored from scans and
721 static void make_black_object(unsigned long ptr)
723 paint_ptr(ptr, KMEMLEAK_BLACK);
727 * Add a scanning area to the object. If at least one such area is added,
728 * kmemleak will only scan these ranges rather than the whole memory block.
730 static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
733 struct kmemleak_object *object;
734 struct kmemleak_scan_area *area;
736 object = find_and_get_object(ptr, 1);
738 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
743 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
745 pr_warning("Cannot allocate a scan area\n");
749 spin_lock_irqsave(&object->lock, flags);
750 if (ptr + size > object->pointer + object->size) {
751 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
752 dump_object_info(object);
753 kmem_cache_free(scan_area_cache, area);
757 INIT_HLIST_NODE(&area->node);
761 hlist_add_head(&area->node, &object->area_list);
763 spin_unlock_irqrestore(&object->lock, flags);
769 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
770 * pointer. Such object will not be scanned by kmemleak but references to it
773 static void object_no_scan(unsigned long ptr)
776 struct kmemleak_object *object;
778 object = find_and_get_object(ptr, 0);
780 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
784 spin_lock_irqsave(&object->lock, flags);
785 object->flags |= OBJECT_NO_SCAN;
786 spin_unlock_irqrestore(&object->lock, flags);
791 * Log an early kmemleak_* call to the early_log buffer. These calls will be
792 * processed later once kmemleak is fully initialized.
794 static void __init log_early(int op_type, const void *ptr, size_t size,
798 struct early_log *log;
800 if (crt_early_log >= ARRAY_SIZE(early_log)) {
801 pr_warning("Early log buffer exceeded, "
802 "please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n");
808 * There is no need for locking since the kernel is still in UP mode
809 * at this stage. Disabling the IRQs is enough.
811 local_irq_save(flags);
812 log = &early_log[crt_early_log];
813 log->op_type = op_type;
816 log->min_count = min_count;
817 log->trace_len = __save_stack_trace(log->trace);
819 local_irq_restore(flags);
823 * Log an early allocated block and populate the stack trace.
825 static void early_alloc(struct early_log *log)
827 struct kmemleak_object *object;
831 if (!atomic_read(&kmemleak_enabled) || !log->ptr || IS_ERR(log->ptr))
835 * RCU locking needed to ensure object is not freed via put_object().
838 object = create_object((unsigned long)log->ptr, log->size,
839 log->min_count, GFP_ATOMIC);
842 spin_lock_irqsave(&object->lock, flags);
843 for (i = 0; i < log->trace_len; i++)
844 object->trace[i] = log->trace[i];
845 object->trace_len = log->trace_len;
846 spin_unlock_irqrestore(&object->lock, flags);
852 * kmemleak_alloc - register a newly allocated object
853 * @ptr: pointer to beginning of the object
854 * @size: size of the object
855 * @min_count: minimum number of references to this object. If during memory
856 * scanning a number of references less than @min_count is found,
857 * the object is reported as a memory leak. If @min_count is 0,
858 * the object is never reported as a leak. If @min_count is -1,
859 * the object is ignored (not scanned and not reported as a leak)
860 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
862 * This function is called from the kernel allocators when a new object
863 * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.).
865 void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
868 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
870 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
871 create_object((unsigned long)ptr, size, min_count, gfp);
872 else if (atomic_read(&kmemleak_early_log))
873 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
875 EXPORT_SYMBOL_GPL(kmemleak_alloc);
878 * kmemleak_free - unregister a previously registered object
879 * @ptr: pointer to beginning of the object
881 * This function is called from the kernel allocators when an object (memory
882 * block) is freed (kmem_cache_free, kfree, vfree etc.).
884 void __ref kmemleak_free(const void *ptr)
886 pr_debug("%s(0x%p)\n", __func__, ptr);
888 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
889 delete_object_full((unsigned long)ptr);
890 else if (atomic_read(&kmemleak_early_log))
891 log_early(KMEMLEAK_FREE, ptr, 0, 0);
893 EXPORT_SYMBOL_GPL(kmemleak_free);
896 * kmemleak_free_part - partially unregister a previously registered object
897 * @ptr: pointer to the beginning or inside the object. This also
898 * represents the start of the range to be freed
899 * @size: size to be unregistered
901 * This function is called when only a part of a memory block is freed
902 * (usually from the bootmem allocator).
904 void __ref kmemleak_free_part(const void *ptr, size_t size)
906 pr_debug("%s(0x%p)\n", __func__, ptr);
908 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
909 delete_object_part((unsigned long)ptr, size);
910 else if (atomic_read(&kmemleak_early_log))
911 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
913 EXPORT_SYMBOL_GPL(kmemleak_free_part);
916 * kmemleak_not_leak - mark an allocated object as false positive
917 * @ptr: pointer to beginning of the object
919 * Calling this function on an object will cause the memory block to no longer
920 * be reported as leak and always be scanned.
922 void __ref kmemleak_not_leak(const void *ptr)
924 pr_debug("%s(0x%p)\n", __func__, ptr);
926 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
927 make_gray_object((unsigned long)ptr);
928 else if (atomic_read(&kmemleak_early_log))
929 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
931 EXPORT_SYMBOL(kmemleak_not_leak);
934 * kmemleak_ignore - ignore an allocated object
935 * @ptr: pointer to beginning of the object
937 * Calling this function on an object will cause the memory block to be
938 * ignored (not scanned and not reported as a leak). This is usually done when
939 * it is known that the corresponding block is not a leak and does not contain
940 * any references to other allocated memory blocks.
942 void __ref kmemleak_ignore(const void *ptr)
944 pr_debug("%s(0x%p)\n", __func__, ptr);
946 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
947 make_black_object((unsigned long)ptr);
948 else if (atomic_read(&kmemleak_early_log))
949 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
951 EXPORT_SYMBOL(kmemleak_ignore);
954 * kmemleak_scan_area - limit the range to be scanned in an allocated object
955 * @ptr: pointer to beginning or inside the object. This also
956 * represents the start of the scan area
957 * @size: size of the scan area
958 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
960 * This function is used when it is known that only certain parts of an object
961 * contain references to other objects. Kmemleak will only scan these areas
962 * reducing the number false negatives.
964 void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
966 pr_debug("%s(0x%p)\n", __func__, ptr);
968 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
969 add_scan_area((unsigned long)ptr, size, gfp);
970 else if (atomic_read(&kmemleak_early_log))
971 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
973 EXPORT_SYMBOL(kmemleak_scan_area);
976 * kmemleak_no_scan - do not scan an allocated object
977 * @ptr: pointer to beginning of the object
979 * This function notifies kmemleak not to scan the given memory block. Useful
980 * in situations where it is known that the given object does not contain any
981 * references to other objects. Kmemleak will not scan such objects reducing
982 * the number of false negatives.
984 void __ref kmemleak_no_scan(const void *ptr)
986 pr_debug("%s(0x%p)\n", __func__, ptr);
988 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
989 object_no_scan((unsigned long)ptr);
990 else if (atomic_read(&kmemleak_early_log))
991 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
993 EXPORT_SYMBOL(kmemleak_no_scan);
996 * Update an object's checksum and return true if it was modified.
998 static bool update_checksum(struct kmemleak_object *object)
1000 u32 old_csum = object->checksum;
1002 if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
1005 object->checksum = crc32(0, (void *)object->pointer, object->size);
1006 return object->checksum != old_csum;
1010 * Memory scanning is a long process and it needs to be interruptable. This
1011 * function checks whether such interrupt condition occurred.
1013 static int scan_should_stop(void)
1015 if (!atomic_read(&kmemleak_enabled))
1019 * This function may be called from either process or kthread context,
1020 * hence the need to check for both stop conditions.
1023 return signal_pending(current);
1025 return kthread_should_stop();
1031 * Scan a memory block (exclusive range) for valid pointers and add those
1032 * found to the gray list.
1034 static void scan_block(void *_start, void *_end,
1035 struct kmemleak_object *scanned, int allow_resched)
1038 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1039 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
1041 for (ptr = start; ptr < end; ptr++) {
1042 struct kmemleak_object *object;
1043 unsigned long flags;
1044 unsigned long pointer;
1048 if (scan_should_stop())
1051 /* don't scan uninitialized memory */
1052 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
1058 object = find_and_get_object(pointer, 1);
1061 if (object == scanned) {
1062 /* self referenced, ignore */
1068 * Avoid the lockdep recursive warning on object->lock being
1069 * previously acquired in scan_object(). These locks are
1070 * enclosed by scan_mutex.
1072 spin_lock_irqsave_nested(&object->lock, flags,
1073 SINGLE_DEPTH_NESTING);
1074 if (!color_white(object)) {
1075 /* non-orphan, ignored or new */
1076 spin_unlock_irqrestore(&object->lock, flags);
1082 * Increase the object's reference count (number of pointers
1083 * to the memory block). If this count reaches the required
1084 * minimum, the object's color will become gray and it will be
1085 * added to the gray_list.
1088 if (color_gray(object)) {
1089 list_add_tail(&object->gray_list, &gray_list);
1090 spin_unlock_irqrestore(&object->lock, flags);
1094 spin_unlock_irqrestore(&object->lock, flags);
1100 * Scan a memory block corresponding to a kmemleak_object. A condition is
1101 * that object->use_count >= 1.
1103 static void scan_object(struct kmemleak_object *object)
1105 struct kmemleak_scan_area *area;
1106 struct hlist_node *elem;
1107 unsigned long flags;
1110 * Once the object->lock is acquired, the corresponding memory block
1111 * cannot be freed (the same lock is acquired in delete_object).
1113 spin_lock_irqsave(&object->lock, flags);
1114 if (object->flags & OBJECT_NO_SCAN)
1116 if (!(object->flags & OBJECT_ALLOCATED))
1117 /* already freed object */
1119 if (hlist_empty(&object->area_list)) {
1120 void *start = (void *)object->pointer;
1121 void *end = (void *)(object->pointer + object->size);
1123 while (start < end && (object->flags & OBJECT_ALLOCATED) &&
1124 !(object->flags & OBJECT_NO_SCAN)) {
1125 scan_block(start, min(start + MAX_SCAN_SIZE, end),
1127 start += MAX_SCAN_SIZE;
1129 spin_unlock_irqrestore(&object->lock, flags);
1131 spin_lock_irqsave(&object->lock, flags);
1134 hlist_for_each_entry(area, elem, &object->area_list, node)
1135 scan_block((void *)area->start,
1136 (void *)(area->start + area->size),
1139 spin_unlock_irqrestore(&object->lock, flags);
1143 * Scan the objects already referenced (gray objects). More objects will be
1144 * referenced and, if there are no memory leaks, all the objects are scanned.
1146 static void scan_gray_list(void)
1148 struct kmemleak_object *object, *tmp;
1151 * The list traversal is safe for both tail additions and removals
1152 * from inside the loop. The kmemleak objects cannot be freed from
1153 * outside the loop because their use_count was incremented.
1155 object = list_entry(gray_list.next, typeof(*object), gray_list);
1156 while (&object->gray_list != &gray_list) {
1159 /* may add new objects to the list */
1160 if (!scan_should_stop())
1161 scan_object(object);
1163 tmp = list_entry(object->gray_list.next, typeof(*object),
1166 /* remove the object from the list and release it */
1167 list_del(&object->gray_list);
1172 WARN_ON(!list_empty(&gray_list));
1176 * Scan data sections and all the referenced memory blocks allocated via the
1177 * kernel's standard allocators. This function must be called with the
1180 static void kmemleak_scan(void)
1182 unsigned long flags;
1183 struct kmemleak_object *object;
1187 jiffies_last_scan = jiffies;
1189 /* prepare the kmemleak_object's */
1191 list_for_each_entry_rcu(object, &object_list, object_list) {
1192 spin_lock_irqsave(&object->lock, flags);
1195 * With a few exceptions there should be a maximum of
1196 * 1 reference to any object at this point.
1198 if (atomic_read(&object->use_count) > 1) {
1199 pr_debug("object->use_count = %d\n",
1200 atomic_read(&object->use_count));
1201 dump_object_info(object);
1204 /* reset the reference count (whiten the object) */
1206 if (color_gray(object) && get_object(object))
1207 list_add_tail(&object->gray_list, &gray_list);
1209 spin_unlock_irqrestore(&object->lock, flags);
1213 /* data/bss scanning */
1214 scan_block(_sdata, _edata, NULL, 1);
1215 scan_block(__bss_start, __bss_stop, NULL, 1);
1218 /* per-cpu sections scanning */
1219 for_each_possible_cpu(i)
1220 scan_block(__per_cpu_start + per_cpu_offset(i),
1221 __per_cpu_end + per_cpu_offset(i), NULL, 1);
1225 * Struct page scanning for each node. The code below is not yet safe
1226 * with MEMORY_HOTPLUG.
1228 for_each_online_node(i) {
1229 pg_data_t *pgdat = NODE_DATA(i);
1230 unsigned long start_pfn = pgdat->node_start_pfn;
1231 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1234 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1237 if (!pfn_valid(pfn))
1239 page = pfn_to_page(pfn);
1240 /* only scan if page is in use */
1241 if (page_count(page) == 0)
1243 scan_block(page, page + 1, NULL, 1);
1248 * Scanning the task stacks (may introduce false negatives).
1250 if (kmemleak_stack_scan) {
1251 struct task_struct *p, *g;
1253 read_lock(&tasklist_lock);
1254 do_each_thread(g, p) {
1255 scan_block(task_stack_page(p), task_stack_page(p) +
1256 THREAD_SIZE, NULL, 0);
1257 } while_each_thread(g, p);
1258 read_unlock(&tasklist_lock);
1262 * Scan the objects already referenced from the sections scanned
1268 * Check for new or unreferenced objects modified since the previous
1269 * scan and color them gray until the next scan.
1272 list_for_each_entry_rcu(object, &object_list, object_list) {
1273 spin_lock_irqsave(&object->lock, flags);
1274 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1275 && update_checksum(object) && get_object(object)) {
1276 /* color it gray temporarily */
1277 object->count = object->min_count;
1278 list_add_tail(&object->gray_list, &gray_list);
1280 spin_unlock_irqrestore(&object->lock, flags);
1285 * Re-scan the gray list for modified unreferenced objects.
1290 * If scanning was stopped do not report any new unreferenced objects.
1292 if (scan_should_stop())
1296 * Scanning result reporting.
1299 list_for_each_entry_rcu(object, &object_list, object_list) {
1300 spin_lock_irqsave(&object->lock, flags);
1301 if (unreferenced_object(object) &&
1302 !(object->flags & OBJECT_REPORTED)) {
1303 object->flags |= OBJECT_REPORTED;
1306 spin_unlock_irqrestore(&object->lock, flags);
1311 pr_info("%d new suspected memory leaks (see "
1312 "/sys/kernel/debug/kmemleak)\n", new_leaks);
1317 * Thread function performing automatic memory scanning. Unreferenced objects
1318 * at the end of a memory scan are reported but only the first time.
1320 static int kmemleak_scan_thread(void *arg)
1322 static int first_run = 1;
1324 pr_info("Automatic memory scanning thread started\n");
1325 set_user_nice(current, 10);
1328 * Wait before the first scan to allow the system to fully initialize.
1332 ssleep(SECS_FIRST_SCAN);
1335 while (!kthread_should_stop()) {
1336 signed long timeout = jiffies_scan_wait;
1338 mutex_lock(&scan_mutex);
1340 mutex_unlock(&scan_mutex);
1342 /* wait before the next scan */
1343 while (timeout && !kthread_should_stop())
1344 timeout = schedule_timeout_interruptible(timeout);
1347 pr_info("Automatic memory scanning thread ended\n");
1353 * Start the automatic memory scanning thread. This function must be called
1354 * with the scan_mutex held.
1356 static void start_scan_thread(void)
1360 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1361 if (IS_ERR(scan_thread)) {
1362 pr_warning("Failed to create the scan thread\n");
1368 * Stop the automatic memory scanning thread. This function must be called
1369 * with the scan_mutex held.
1371 static void stop_scan_thread(void)
1374 kthread_stop(scan_thread);
1380 * Iterate over the object_list and return the first valid object at or after
1381 * the required position with its use_count incremented. The function triggers
1382 * a memory scanning when the pos argument points to the first position.
1384 static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1386 struct kmemleak_object *object;
1390 err = mutex_lock_interruptible(&scan_mutex);
1392 return ERR_PTR(err);
1395 list_for_each_entry_rcu(object, &object_list, object_list) {
1398 if (get_object(object))
1407 * Return the next object in the object_list. The function decrements the
1408 * use_count of the previous object and increases that of the next one.
1410 static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1412 struct kmemleak_object *prev_obj = v;
1413 struct kmemleak_object *next_obj = NULL;
1414 struct list_head *n = &prev_obj->object_list;
1418 list_for_each_continue_rcu(n, &object_list) {
1419 struct kmemleak_object *obj =
1420 list_entry(n, struct kmemleak_object, object_list);
1421 if (get_object(obj)) {
1427 put_object(prev_obj);
1432 * Decrement the use_count of the last object required, if any.
1434 static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1438 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1439 * waiting was interrupted, so only release it if !IS_ERR.
1442 mutex_unlock(&scan_mutex);
1449 * Print the information for an unreferenced object to the seq file.
1451 static int kmemleak_seq_show(struct seq_file *seq, void *v)
1453 struct kmemleak_object *object = v;
1454 unsigned long flags;
1456 spin_lock_irqsave(&object->lock, flags);
1457 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
1458 print_unreferenced(seq, object);
1459 spin_unlock_irqrestore(&object->lock, flags);
1463 static const struct seq_operations kmemleak_seq_ops = {
1464 .start = kmemleak_seq_start,
1465 .next = kmemleak_seq_next,
1466 .stop = kmemleak_seq_stop,
1467 .show = kmemleak_seq_show,
1470 static int kmemleak_open(struct inode *inode, struct file *file)
1472 if (!atomic_read(&kmemleak_enabled))
1475 return seq_open(file, &kmemleak_seq_ops);
1478 static int kmemleak_release(struct inode *inode, struct file *file)
1480 return seq_release(inode, file);
1483 static int dump_str_object_info(const char *str)
1485 unsigned long flags;
1486 struct kmemleak_object *object;
1489 addr= simple_strtoul(str, NULL, 0);
1490 object = find_and_get_object(addr, 0);
1492 pr_info("Unknown object at 0x%08lx\n", addr);
1496 spin_lock_irqsave(&object->lock, flags);
1497 dump_object_info(object);
1498 spin_unlock_irqrestore(&object->lock, flags);
1505 * We use grey instead of black to ensure we can do future scans on the same
1506 * objects. If we did not do future scans these black objects could
1507 * potentially contain references to newly allocated objects in the future and
1508 * we'd end up with false positives.
1510 static void kmemleak_clear(void)
1512 struct kmemleak_object *object;
1513 unsigned long flags;
1516 list_for_each_entry_rcu(object, &object_list, object_list) {
1517 spin_lock_irqsave(&object->lock, flags);
1518 if ((object->flags & OBJECT_REPORTED) &&
1519 unreferenced_object(object))
1520 __paint_it(object, KMEMLEAK_GREY);
1521 spin_unlock_irqrestore(&object->lock, flags);
1527 * File write operation to configure kmemleak at run-time. The following
1528 * commands can be written to the /sys/kernel/debug/kmemleak file:
1529 * off - disable kmemleak (irreversible)
1530 * stack=on - enable the task stacks scanning
1531 * stack=off - disable the tasks stacks scanning
1532 * scan=on - start the automatic memory scanning thread
1533 * scan=off - stop the automatic memory scanning thread
1534 * scan=... - set the automatic memory scanning period in seconds (0 to
1536 * scan - trigger a memory scan
1537 * clear - mark all current reported unreferenced kmemleak objects as
1538 * grey to ignore printing them
1539 * dump=... - dump information about the object found at the given address
1541 static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1542 size_t size, loff_t *ppos)
1548 buf_size = min(size, (sizeof(buf) - 1));
1549 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1553 ret = mutex_lock_interruptible(&scan_mutex);
1557 if (strncmp(buf, "off", 3) == 0)
1559 else if (strncmp(buf, "stack=on", 8) == 0)
1560 kmemleak_stack_scan = 1;
1561 else if (strncmp(buf, "stack=off", 9) == 0)
1562 kmemleak_stack_scan = 0;
1563 else if (strncmp(buf, "scan=on", 7) == 0)
1564 start_scan_thread();
1565 else if (strncmp(buf, "scan=off", 8) == 0)
1567 else if (strncmp(buf, "scan=", 5) == 0) {
1570 ret = strict_strtoul(buf + 5, 0, &secs);
1575 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1576 start_scan_thread();
1578 } else if (strncmp(buf, "scan", 4) == 0)
1580 else if (strncmp(buf, "clear", 5) == 0)
1582 else if (strncmp(buf, "dump=", 5) == 0)
1583 ret = dump_str_object_info(buf + 5);
1588 mutex_unlock(&scan_mutex);
1592 /* ignore the rest of the buffer, only one command at a time */
1597 static const struct file_operations kmemleak_fops = {
1598 .owner = THIS_MODULE,
1599 .open = kmemleak_open,
1601 .write = kmemleak_write,
1602 .llseek = seq_lseek,
1603 .release = kmemleak_release,
1607 * Perform the freeing of the kmemleak internal objects after waiting for any
1608 * current memory scan to complete.
1610 static void kmemleak_do_cleanup(struct work_struct *work)
1612 struct kmemleak_object *object;
1614 mutex_lock(&scan_mutex);
1618 list_for_each_entry_rcu(object, &object_list, object_list)
1619 delete_object_full(object->pointer);
1621 mutex_unlock(&scan_mutex);
1624 static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
1627 * Disable kmemleak. No memory allocation/freeing will be traced once this
1628 * function is called. Disabling kmemleak is an irreversible operation.
1630 static void kmemleak_disable(void)
1632 /* atomically check whether it was already invoked */
1633 if (atomic_cmpxchg(&kmemleak_error, 0, 1))
1636 /* stop any memory operation tracing */
1637 atomic_set(&kmemleak_early_log, 0);
1638 atomic_set(&kmemleak_enabled, 0);
1640 /* check whether it is too early for a kernel thread */
1641 if (atomic_read(&kmemleak_initialized))
1642 schedule_work(&cleanup_work);
1644 pr_info("Kernel memory leak detector disabled\n");
1648 * Allow boot-time kmemleak disabling (enabled by default).
1650 static int kmemleak_boot_config(char *str)
1654 if (strcmp(str, "off") == 0)
1656 else if (strcmp(str, "on") == 0)
1657 kmemleak_skip_disable = 1;
1662 early_param("kmemleak", kmemleak_boot_config);
1664 static void __init print_log_trace(struct early_log *log)
1666 struct stack_trace trace;
1668 trace.nr_entries = log->trace_len;
1669 trace.entries = log->trace;
1671 pr_notice("Early log backtrace:\n");
1672 print_stack_trace(&trace, 2);
1676 * Kmemleak initialization.
1678 void __init kmemleak_init(void)
1681 unsigned long flags;
1683 #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
1684 if (!kmemleak_skip_disable) {
1690 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
1691 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
1693 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
1694 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
1695 INIT_PRIO_TREE_ROOT(&object_tree_root);
1697 /* the kernel is still in UP mode, so disabling the IRQs is enough */
1698 local_irq_save(flags);
1699 if (!atomic_read(&kmemleak_error)) {
1700 atomic_set(&kmemleak_enabled, 1);
1701 atomic_set(&kmemleak_early_log, 0);
1703 local_irq_restore(flags);
1706 * This is the point where tracking allocations is safe. Automatic
1707 * scanning is started during the late initcall. Add the early logged
1708 * callbacks to the kmemleak infrastructure.
1710 for (i = 0; i < crt_early_log; i++) {
1711 struct early_log *log = &early_log[i];
1713 switch (log->op_type) {
1714 case KMEMLEAK_ALLOC:
1718 kmemleak_free(log->ptr);
1720 case KMEMLEAK_FREE_PART:
1721 kmemleak_free_part(log->ptr, log->size);
1723 case KMEMLEAK_NOT_LEAK:
1724 kmemleak_not_leak(log->ptr);
1726 case KMEMLEAK_IGNORE:
1727 kmemleak_ignore(log->ptr);
1729 case KMEMLEAK_SCAN_AREA:
1730 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
1732 case KMEMLEAK_NO_SCAN:
1733 kmemleak_no_scan(log->ptr);
1736 kmemleak_warn("Unknown early log operation: %d\n",
1740 if (atomic_read(&kmemleak_warning)) {
1741 print_log_trace(log);
1742 atomic_set(&kmemleak_warning, 0);
1748 * Late initialization function.
1750 static int __init kmemleak_late_init(void)
1752 struct dentry *dentry;
1754 atomic_set(&kmemleak_initialized, 1);
1756 if (atomic_read(&kmemleak_error)) {
1758 * Some error occurred and kmemleak was disabled. There is a
1759 * small chance that kmemleak_disable() was called immediately
1760 * after setting kmemleak_initialized and we may end up with
1761 * two clean-up threads but serialized by scan_mutex.
1763 schedule_work(&cleanup_work);
1767 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
1770 pr_warning("Failed to create the debugfs kmemleak file\n");
1771 mutex_lock(&scan_mutex);
1772 start_scan_thread();
1773 mutex_unlock(&scan_mutex);
1775 pr_info("Kernel memory leak detector initialized\n");
1779 late_initcall(kmemleak_late_init);