1/*
2 * mm/kmemleak.c
3 *
4 * Copyright (C) 2008 ARM Limited
5 * Written by Catalin Marinas <catalin.marinas@arm.com>
6 *
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.
10 *
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.
15 *
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
19 *
20 *
21 * For more information on the algorithm and kmemleak usage, please see
22 * Documentation/dev-tools/kmemleak.rst.
23 *
24 * Notes on locking
25 * ----------------
26 *
27 * The following locks and mutexes are used by kmemleak:
28 *
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 red black 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
54 * pointer
55 *
56 * Locks and mutexes are acquired/nested in the following order:
57 *
58 * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING)
59 *
60 * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex
61 * regions.
62 *
63 * The kmemleak_object structures have a use_count incremented or decremented
64 * using the get_object()/put_object() functions. When the use_count becomes
65 * 0, this count can no longer be incremented and put_object() schedules the
66 * kmemleak_object freeing via an RCU callback. All calls to the get_object()
67 * function must be protected by rcu_read_lock() to avoid accessing a freed
68 * structure.
69 */
70
71#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
72
73#include <linux/init.h>
74#include <linux/kernel.h>
75#include <linux/list.h>
76#include <linux/sched/signal.h>
77#include <linux/sched/task.h>
78#include <linux/sched/task_stack.h>
79#include <linux/jiffies.h>
80#include <linux/delay.h>
81#include <linux/export.h>
82#include <linux/kthread.h>
83#include <linux/rbtree.h>
84#include <linux/fs.h>
85#include <linux/debugfs.h>
86#include <linux/seq_file.h>
87#include <linux/cpumask.h>
88#include <linux/spinlock.h>
89#include <linux/module.h>
90#include <linux/mutex.h>
91#include <linux/rcupdate.h>
92#include <linux/stacktrace.h>
93#include <linux/cache.h>
94#include <linux/percpu.h>
95#include <linux/memblock.h>
96#include <linux/pfn.h>
97#include <linux/mmzone.h>
98#include <linux/slab.h>
99#include <linux/thread_info.h>
100#include <linux/err.h>
101#include <linux/uaccess.h>
102#include <linux/string.h>
103#include <linux/nodemask.h>
104#include <linux/mm.h>
105#include <linux/workqueue.h>
106#include <linux/crc32.h>
107
108#include <asm/sections.h>
109#include <asm/processor.h>
110#include <linux/atomic.h>
111
112#include <linux/kasan.h>
113#include <linux/kmemleak.h>
114#include <linux/memory_hotplug.h>
115
116/*
117 * Kmemleak configuration and common defines.
118 */
119#define MAX_TRACE 16 /* stack trace length */
120#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
121#define SECS_FIRST_SCAN 60 /* delay before the first scan */
122#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
123#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
124
125#define BYTES_PER_POINTER sizeof(void *)
126
127/* GFP bitmask for kmemleak internal allocations */
128#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
129 __GFP_NORETRY | __GFP_NOMEMALLOC | \
130 __GFP_NOWARN | __GFP_NOFAIL)
131
132/* scanning area inside a memory block */
133struct kmemleak_scan_area {
134 struct hlist_node node;
135 unsigned long start;
136 size_t size;
137};
138
139#define KMEMLEAK_GREY 0
140#define KMEMLEAK_BLACK -1
141
142/*
143 * Structure holding the metadata for each allocated memory block.
144 * Modifications to such objects should be made while holding the
145 * object->lock. Insertions or deletions from object_list, gray_list or
146 * rb_node are already protected by the corresponding locks or mutex (see
147 * the notes on locking above). These objects are reference-counted
148 * (use_count) and freed using the RCU mechanism.
149 */
150struct kmemleak_object {
151 spinlock_t lock;
152 unsigned int flags; /* object status flags */
153 struct list_head object_list;
154 struct list_head gray_list;
155 struct rb_node rb_node;
156 struct rcu_head rcu; /* object_list lockless traversal */
157 /* object usage count; object freed when use_count == 0 */
158 atomic_t use_count;
159 unsigned long pointer;
160 size_t size;
161 /* pass surplus references to this pointer */
162 unsigned long excess_ref;
163 /* minimum number of a pointers found before it is considered leak */
164 int min_count;
165 /* the total number of pointers found pointing to this object */
166 int count;
167 /* checksum for detecting modified objects */
168 u32 checksum;
169 /* memory ranges to be scanned inside an object (empty for all) */
170 struct hlist_head area_list;
171 unsigned long trace[MAX_TRACE];
172 unsigned int trace_len;
173 unsigned long jiffies; /* creation timestamp */
174 pid_t pid; /* pid of the current task */
175 char comm[TASK_COMM_LEN]; /* executable name */
176};
177
178/* flag representing the memory block allocation status */
179#define OBJECT_ALLOCATED (1 << 0)
180/* flag set after the first reporting of an unreference object */
181#define OBJECT_REPORTED (1 << 1)
182/* flag set to not scan the object */
183#define OBJECT_NO_SCAN (1 << 2)
184
185#define HEX_PREFIX " "
186/* number of bytes to print per line; must be 16 or 32 */
187#define HEX_ROW_SIZE 16
188/* number of bytes to print at a time (1, 2, 4, 8) */
189#define HEX_GROUP_SIZE 1
190/* include ASCII after the hex output */
191#define HEX_ASCII 1
192/* max number of lines to be printed */
193#define HEX_MAX_LINES 2
194
195/* the list of all allocated objects */
196static LIST_HEAD(object_list);
197/* the list of gray-colored objects (see color_gray comment below) */
198static LIST_HEAD(gray_list);
199/* search tree for object boundaries */
200static struct rb_root object_tree_root = RB_ROOT;
201/* rw_lock protecting the access to object_list and object_tree_root */
202static DEFINE_RWLOCK(kmemleak_lock);
203
204/* allocation caches for kmemleak internal data */
205static struct kmem_cache *object_cache;
206static struct kmem_cache *scan_area_cache;
207
208/* set if tracing memory operations is enabled */
209static int kmemleak_enabled;
210/* same as above but only for the kmemleak_free() callback */
211static int kmemleak_free_enabled;
212/* set in the late_initcall if there were no errors */
213static int kmemleak_initialized;
214/* enables or disables early logging of the memory operations */
215static int kmemleak_early_log = 1;
216/* set if a kmemleak warning was issued */
217static int kmemleak_warning;
218/* set if a fatal kmemleak error has occurred */
219static int kmemleak_error;
220
221/* minimum and maximum address that may be valid pointers */
222static unsigned long min_addr = ULONG_MAX;
223static unsigned long max_addr;
224
225static struct task_struct *scan_thread;
226/* used to avoid reporting of recently allocated objects */
227static unsigned long jiffies_min_age;
228static unsigned long jiffies_last_scan;
229/* delay between automatic memory scannings */
230static signed long jiffies_scan_wait;
231/* enables or disables the task stacks scanning */
232static int kmemleak_stack_scan = 1;
233/* protects the memory scanning, parameters and debug/kmemleak file access */
234static DEFINE_MUTEX(scan_mutex);
235/* setting kmemleak=on, will set this var, skipping the disable */
236static int kmemleak_skip_disable;
237/* If there are leaks that can be reported */
238static bool kmemleak_found_leaks;
239
240static bool kmemleak_verbose;
241module_param_named(verbose, kmemleak_verbose, bool, 0600);
242
243/*
244 * Early object allocation/freeing logging. Kmemleak is initialized after the
245 * kernel allocator. However, both the kernel allocator and kmemleak may
246 * allocate memory blocks which need to be tracked. Kmemleak defines an
247 * arbitrary buffer to hold the allocation/freeing information before it is
248 * fully initialized.
249 */
250
251/* kmemleak operation type for early logging */
252enum {
253 KMEMLEAK_ALLOC,
254 KMEMLEAK_ALLOC_PERCPU,
255 KMEMLEAK_FREE,
256 KMEMLEAK_FREE_PART,
257 KMEMLEAK_FREE_PERCPU,
258 KMEMLEAK_NOT_LEAK,
259 KMEMLEAK_IGNORE,
260 KMEMLEAK_SCAN_AREA,
261 KMEMLEAK_NO_SCAN,
262 KMEMLEAK_SET_EXCESS_REF
263};
264
265/*
266 * Structure holding the information passed to kmemleak callbacks during the
267 * early logging.
268 */
269struct early_log {
270 int op_type; /* kmemleak operation type */
271 int min_count; /* minimum reference count */
272 const void *ptr; /* allocated/freed memory block */
273 union {
274 size_t size; /* memory block size */
275 unsigned long excess_ref; /* surplus reference passing */
276 };
277 unsigned long trace[MAX_TRACE]; /* stack trace */
278 unsigned int trace_len; /* stack trace length */
279};
280
281/* early logging buffer and current position */
282static struct early_log
283 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
284static int crt_early_log __initdata;
285
286static void kmemleak_disable(void);
287
288/*
289 * Print a warning and dump the stack trace.
290 */
291#define kmemleak_warn(x...) do { \
292 pr_warn(x); \
293 dump_stack(); \
294 kmemleak_warning = 1; \
295} while (0)
296
297/*
298 * Macro invoked when a serious kmemleak condition occurred and cannot be
299 * recovered from. Kmemleak will be disabled and further allocation/freeing
300 * tracing no longer available.
301 */
302#define kmemleak_stop(x...) do { \
303 kmemleak_warn(x); \
304 kmemleak_disable(); \
305} while (0)
306
307#define warn_or_seq_printf(seq, fmt, ...) do { \
308 if (seq) \
309 seq_printf(seq, fmt, ##__VA_ARGS__); \
310 else \
311 pr_warn(fmt, ##__VA_ARGS__); \
312} while (0)
313
314static void warn_or_seq_hex_dump(struct seq_file *seq, int prefix_type,
315 int rowsize, int groupsize, const void *buf,
316 size_t len, bool ascii)
317{
318 if (seq)
319 seq_hex_dump(seq, HEX_PREFIX, prefix_type, rowsize, groupsize,
320 buf, len, ascii);
321 else
322 print_hex_dump(KERN_WARNING, pr_fmt(HEX_PREFIX), prefix_type,
323 rowsize, groupsize, buf, len, ascii);
324}
325
326/*
327 * Printing of the objects hex dump to the seq file. The number of lines to be
328 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
329 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
330 * with the object->lock held.
331 */
332static void hex_dump_object(struct seq_file *seq,
333 struct kmemleak_object *object)
334{
335 const u8 *ptr = (const u8 *)object->pointer;
336 size_t len;
337
338 /* limit the number of lines to HEX_MAX_LINES */
339 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
340
341 warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len);
342 kasan_disable_current();
343 warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE,
344 HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
345 kasan_enable_current();
346}
347
348/*
349 * Object colors, encoded with count and min_count:
350 * - white - orphan object, not enough references to it (count < min_count)
351 * - gray - not orphan, not marked as false positive (min_count == 0) or
352 * sufficient references to it (count >= min_count)
353 * - black - ignore, it doesn't contain references (e.g. text section)
354 * (min_count == -1). No function defined for this color.
355 * Newly created objects don't have any color assigned (object->count == -1)
356 * before the next memory scan when they become white.
357 */
358static bool color_white(const struct kmemleak_object *object)
359{
360 return object->count != KMEMLEAK_BLACK &&
361 object->count < object->min_count;
362}
363
364static bool color_gray(const struct kmemleak_object *object)
365{
366 return object->min_count != KMEMLEAK_BLACK &&
367 object->count >= object->min_count;
368}
369
370/*
371 * Objects are considered unreferenced only if their color is white, they have
372 * not be deleted and have a minimum age to avoid false positives caused by
373 * pointers temporarily stored in CPU registers.
374 */
375static bool unreferenced_object(struct kmemleak_object *object)
376{
377 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
378 time_before_eq(object->jiffies + jiffies_min_age,
379 jiffies_last_scan);
380}
381
382/*
383 * Printing of the unreferenced objects information to the seq file. The
384 * print_unreferenced function must be called with the object->lock held.
385 */
386static void print_unreferenced(struct seq_file *seq,
387 struct kmemleak_object *object)
388{
389 int i;
390 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
391
392 warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
393 object->pointer, object->size);
394 warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
395 object->comm, object->pid, object->jiffies,
396 msecs_age / 1000, msecs_age % 1000);
397 hex_dump_object(seq, object);
398 warn_or_seq_printf(seq, " backtrace:\n");
399
400 for (i = 0; i < object->trace_len; i++) {
401 void *ptr = (void *)object->trace[i];
402 warn_or_seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
403 }
404}
405
406/*
407 * Print the kmemleak_object information. This function is used mainly for
408 * debugging special cases when kmemleak operations. It must be called with
409 * the object->lock held.
410 */
411static void dump_object_info(struct kmemleak_object *object)
412{
413 struct stack_trace trace;
414
415 trace.nr_entries = object->trace_len;
416 trace.entries = object->trace;
417
418 pr_notice("Object 0x%08lx (size %zu):\n",
419 object->pointer, object->size);
420 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
421 object->comm, object->pid, object->jiffies);
422 pr_notice(" min_count = %d\n", object->min_count);
423 pr_notice(" count = %d\n", object->count);
424 pr_notice(" flags = 0x%x\n", object->flags);
425 pr_notice(" checksum = %u\n", object->checksum);
426 pr_notice(" backtrace:\n");
427 print_stack_trace(&trace, 4);
428}
429
430/*
431 * Look-up a memory block metadata (kmemleak_object) in the object search
432 * tree based on a pointer value. If alias is 0, only values pointing to the
433 * beginning of the memory block are allowed. The kmemleak_lock must be held
434 * when calling this function.
435 */
436static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
437{
438 struct rb_node *rb = object_tree_root.rb_node;
439
440 while (rb) {
441 struct kmemleak_object *object =
442 rb_entry(rb, struct kmemleak_object, rb_node);
443 if (ptr < object->pointer)
444 rb = object->rb_node.rb_left;
445 else if (object->pointer + object->size <= ptr)
446 rb = object->rb_node.rb_right;
447 else if (object->pointer == ptr || alias)
448 return object;
449 else {
450 kmemleak_warn("Found object by alias at 0x%08lx\n",
451 ptr);
452 dump_object_info(object);
453 break;
454 }
455 }
456 return NULL;
457}
458
459/*
460 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
461 * that once an object's use_count reached 0, the RCU freeing was already
462 * registered and the object should no longer be used. This function must be
463 * called under the protection of rcu_read_lock().
464 */
465static int get_object(struct kmemleak_object *object)
466{
467 return atomic_inc_not_zero(&object->use_count);
468}
469
470/*
471 * RCU callback to free a kmemleak_object.
472 */
473static void free_object_rcu(struct rcu_head *rcu)
474{
475 struct hlist_node *tmp;
476 struct kmemleak_scan_area *area;
477 struct kmemleak_object *object =
478 container_of(rcu, struct kmemleak_object, rcu);
479
480 /*
481 * Once use_count is 0 (guaranteed by put_object), there is no other
482 * code accessing this object, hence no need for locking.
483 */
484 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
485 hlist_del(&area->node);
486 kmem_cache_free(scan_area_cache, area);
487 }
488 kmem_cache_free(object_cache, object);
489}
490
491/*
492 * Decrement the object use_count. Once the count is 0, free the object using
493 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
494 * delete_object() path, the delayed RCU freeing ensures that there is no
495 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
496 * is also possible.
497 */
498static void put_object(struct kmemleak_object *object)
499{
500 if (!atomic_dec_and_test(&object->use_count))
501 return;
502
503 /* should only get here after delete_object was called */
504 WARN_ON(object->flags & OBJECT_ALLOCATED);
505
506 call_rcu(&object->rcu, free_object_rcu);
507}
508
509/*
510 * Look up an object in the object search tree and increase its use_count.
511 */
512static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
513{
514 unsigned long flags;
515 struct kmemleak_object *object;
516
517 rcu_read_lock();
518 read_lock_irqsave(&kmemleak_lock, flags);
519 object = lookup_object(ptr, alias);
520 read_unlock_irqrestore(&kmemleak_lock, flags);
521
522 /* check whether the object is still available */
523 if (object && !get_object(object))
524 object = NULL;
525 rcu_read_unlock();
526
527 return object;
528}
529
530/*
531 * Look up an object in the object search tree and remove it from both
532 * object_tree_root and object_list. The returned object's use_count should be
533 * at least 1, as initially set by create_object().
534 */
535static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
536{
537 unsigned long flags;
538 struct kmemleak_object *object;
539
540 write_lock_irqsave(&kmemleak_lock, flags);
541 object = lookup_object(ptr, alias);
542 if (object) {
543 rb_erase(&object->rb_node, &object_tree_root);
544 list_del_rcu(&object->object_list);
545 }
546 write_unlock_irqrestore(&kmemleak_lock, flags);
547
548 return object;
549}
550
551/*
552 * Save stack trace to the given array of MAX_TRACE size.
553 */
554static int __save_stack_trace(unsigned long *trace)
555{
556 struct stack_trace stack_trace;
557
558 stack_trace.max_entries = MAX_TRACE;
559 stack_trace.nr_entries = 0;
560 stack_trace.entries = trace;
561 stack_trace.skip = 2;
562 save_stack_trace(&stack_trace);
563
564 return stack_trace.nr_entries;
565}
566
567/*
568 * Create the metadata (struct kmemleak_object) corresponding to an allocated
569 * memory block and add it to the object_list and object_tree_root.
570 */
571static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
572 int min_count, gfp_t gfp)
573{
574 unsigned long flags;
575 struct kmemleak_object *object, *parent;
576 struct rb_node **link, *rb_parent;
577 unsigned long untagged_ptr;
578
579 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
580 if (!object) {
581 pr_warn("Cannot allocate a kmemleak_object structure\n");
582 kmemleak_disable();
583 return NULL;
584 }
585
586 INIT_LIST_HEAD(&object->object_list);
587 INIT_LIST_HEAD(&object->gray_list);
588 INIT_HLIST_HEAD(&object->area_list);
589 spin_lock_init(&object->lock);
590 atomic_set(&object->use_count, 1);
591 object->flags = OBJECT_ALLOCATED;
592 object->pointer = ptr;
593 object->size = size;
594 object->excess_ref = 0;
595 object->min_count = min_count;
596 object->count = 0; /* white color initially */
597 object->jiffies = jiffies;
598 object->checksum = 0;
599
600 /* task information */
601 if (in_irq()) {
602 object->pid = 0;
603 strncpy(object->comm, "hardirq", sizeof(object->comm));
604 } else if (in_softirq()) {
605 object->pid = 0;
606 strncpy(object->comm, "softirq", sizeof(object->comm));
607 } else {
608 object->pid = current->pid;
609 /*
610 * There is a small chance of a race with set_task_comm(),
611 * however using get_task_comm() here may cause locking
612 * dependency issues with current->alloc_lock. In the worst
613 * case, the command line is not correct.
614 */
615 strncpy(object->comm, current->comm, sizeof(object->comm));
616 }
617
618 /* kernel backtrace */
619 object->trace_len = __save_stack_trace(object->trace);
620
621 write_lock_irqsave(&kmemleak_lock, flags);
622
623 untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
624 min_addr = min(min_addr, untagged_ptr);
625 max_addr = max(max_addr, untagged_ptr + size);
626 link = &object_tree_root.rb_node;
627 rb_parent = NULL;
628 while (*link) {
629 rb_parent = *link;
630 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
631 if (ptr + size <= parent->pointer)
632 link = &parent->rb_node.rb_left;
633 else if (parent->pointer + parent->size <= ptr)
634 link = &parent->rb_node.rb_right;
635 else {
636 kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
637 ptr);
638 /*
639 * No need for parent->lock here since "parent" cannot
640 * be freed while the kmemleak_lock is held.
641 */
642 dump_object_info(parent);
643 kmem_cache_free(object_cache, object);
644 object = NULL;
645 goto out;
646 }
647 }
648 rb_link_node(&object->rb_node, rb_parent, link);
649 rb_insert_color(&object->rb_node, &object_tree_root);
650
651 list_add_tail_rcu(&object->object_list, &object_list);
652out:
653 write_unlock_irqrestore(&kmemleak_lock, flags);
654 return object;
655}
656
657/*
658 * Mark the object as not allocated and schedule RCU freeing via put_object().
659 */
660static void __delete_object(struct kmemleak_object *object)
661{
662 unsigned long flags;
663
664 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
665 WARN_ON(atomic_read(&object->use_count) < 1);
666
667 /*
668 * Locking here also ensures that the corresponding memory block
669 * cannot be freed when it is being scanned.
670 */
671 spin_lock_irqsave(&object->lock, flags);
672 object->flags &= ~OBJECT_ALLOCATED;
673 spin_unlock_irqrestore(&object->lock, flags);
674 put_object(object);
675}
676
677/*
678 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
679 * delete it.
680 */
681static void delete_object_full(unsigned long ptr)
682{
683 struct kmemleak_object *object;
684
685 object = find_and_remove_object(ptr, 0);
686 if (!object) {
687#ifdef DEBUG
688 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
689 ptr);
690#endif
691 return;
692 }
693 __delete_object(object);
694}
695
696/*
697 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
698 * delete it. If the memory block is partially freed, the function may create
699 * additional metadata for the remaining parts of the block.
700 */
701static void delete_object_part(unsigned long ptr, size_t size)
702{
703 struct kmemleak_object *object;
704 unsigned long start, end;
705
706 object = find_and_remove_object(ptr, 1);
707 if (!object) {
708#ifdef DEBUG
709 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
710 ptr, size);
711#endif
712 return;
713 }
714
715 /*
716 * Create one or two objects that may result from the memory block
717 * split. Note that partial freeing is only done by free_bootmem() and
718 * this happens before kmemleak_init() is called. The path below is
719 * only executed during early log recording in kmemleak_init(), so
720 * GFP_KERNEL is enough.
721 */
722 start = object->pointer;
723 end = object->pointer + object->size;
724 if (ptr > start)
725 create_object(start, ptr - start, object->min_count,
726 GFP_KERNEL);
727 if (ptr + size < end)
728 create_object(ptr + size, end - ptr - size, object->min_count,
729 GFP_KERNEL);
730
731 __delete_object(object);
732}
733
734static void __paint_it(struct kmemleak_object *object, int color)
735{
736 object->min_count = color;
737 if (color == KMEMLEAK_BLACK)
738 object->flags |= OBJECT_NO_SCAN;
739}
740
741static void paint_it(struct kmemleak_object *object, int color)
742{
743 unsigned long flags;
744
745 spin_lock_irqsave(&object->lock, flags);
746 __paint_it(object, color);
747 spin_unlock_irqrestore(&object->lock, flags);
748}
749
750static void paint_ptr(unsigned long ptr, int color)
751{
752 struct kmemleak_object *object;
753
754 object = find_and_get_object(ptr, 0);
755 if (!object) {
756 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
757 ptr,
758 (color == KMEMLEAK_GREY) ? "Grey" :
759 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
760 return;
761 }
762 paint_it(object, color);
763 put_object(object);
764}
765
766/*
767 * Mark an object permanently as gray-colored so that it can no longer be
768 * reported as a leak. This is used in general to mark a false positive.
769 */
770static void make_gray_object(unsigned long ptr)
771{
772 paint_ptr(ptr, KMEMLEAK_GREY);
773}
774
775/*
776 * Mark the object as black-colored so that it is ignored from scans and
777 * reporting.
778 */
779static void make_black_object(unsigned long ptr)
780{
781 paint_ptr(ptr, KMEMLEAK_BLACK);
782}
783
784/*
785 * Add a scanning area to the object. If at least one such area is added,
786 * kmemleak will only scan these ranges rather than the whole memory block.
787 */
788static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
789{
790 unsigned long flags;
791 struct kmemleak_object *object;
792 struct kmemleak_scan_area *area;
793
794 object = find_and_get_object(ptr, 1);
795 if (!object) {
796 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
797 ptr);
798 return;
799 }
800
801 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
802 if (!area) {
803 pr_warn("Cannot allocate a scan area\n");
804 goto out;
805 }
806
807 spin_lock_irqsave(&object->lock, flags);
808 if (size == SIZE_MAX) {
809 size = object->pointer + object->size - ptr;
810 } else if (ptr + size > object->pointer + object->size) {
811 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
812 dump_object_info(object);
813 kmem_cache_free(scan_area_cache, area);
814 goto out_unlock;
815 }
816
817 INIT_HLIST_NODE(&area->node);
818 area->start = ptr;
819 area->size = size;
820
821 hlist_add_head(&area->node, &object->area_list);
822out_unlock:
823 spin_unlock_irqrestore(&object->lock, flags);
824out:
825 put_object(object);
826}
827
828/*
829 * Any surplus references (object already gray) to 'ptr' are passed to
830 * 'excess_ref'. This is used in the vmalloc() case where a pointer to
831 * vm_struct may be used as an alternative reference to the vmalloc'ed object
832 * (see free_thread_stack()).
833 */
834static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
835{
836 unsigned long flags;
837 struct kmemleak_object *object;
838
839 object = find_and_get_object(ptr, 0);
840 if (!object) {
841 kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
842 ptr);
843 return;
844 }
845
846 spin_lock_irqsave(&object->lock, flags);
847 object->excess_ref = excess_ref;
848 spin_unlock_irqrestore(&object->lock, flags);
849 put_object(object);
850}
851
852/*
853 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
854 * pointer. Such object will not be scanned by kmemleak but references to it
855 * are searched.
856 */
857static void object_no_scan(unsigned long ptr)
858{
859 unsigned long flags;
860 struct kmemleak_object *object;
861
862 object = find_and_get_object(ptr, 0);
863 if (!object) {
864 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
865 return;
866 }
867
868 spin_lock_irqsave(&object->lock, flags);
869 object->flags |= OBJECT_NO_SCAN;
870 spin_unlock_irqrestore(&object->lock, flags);
871 put_object(object);
872}
873
874/*
875 * Log an early kmemleak_* call to the early_log buffer. These calls will be
876 * processed later once kmemleak is fully initialized.
877 */
878static void __init log_early(int op_type, const void *ptr, size_t size,
879 int min_count)
880{
881 unsigned long flags;
882 struct early_log *log;
883
884 if (kmemleak_error) {
885 /* kmemleak stopped recording, just count the requests */
886 crt_early_log++;
887 return;
888 }
889
890 if (crt_early_log >= ARRAY_SIZE(early_log)) {
891 crt_early_log++;
892 kmemleak_disable();
893 return;
894 }
895
896 /*
897 * There is no need for locking since the kernel is still in UP mode
898 * at this stage. Disabling the IRQs is enough.
899 */
900 local_irq_save(flags);
901 log = &early_log[crt_early_log];
902 log->op_type = op_type;
903 log->ptr = ptr;
904 log->size = size;
905 log->min_count = min_count;
906 log->trace_len = __save_stack_trace(log->trace);
907 crt_early_log++;
908 local_irq_restore(flags);
909}
910
911/*
912 * Log an early allocated block and populate the stack trace.
913 */
914static void early_alloc(struct early_log *log)
915{
916 struct kmemleak_object *object;
917 unsigned long flags;
918 int i;
919
920 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
921 return;
922
923 /*
924 * RCU locking needed to ensure object is not freed via put_object().
925 */
926 rcu_read_lock();
927 object = create_object((unsigned long)log->ptr, log->size,
928 log->min_count, GFP_ATOMIC);
929 if (!object)
930 goto out;
931 spin_lock_irqsave(&object->lock, flags);
932 for (i = 0; i < log->trace_len; i++)
933 object->trace[i] = log->trace[i];
934 object->trace_len = log->trace_len;
935 spin_unlock_irqrestore(&object->lock, flags);
936out:
937 rcu_read_unlock();
938}
939
940/*
941 * Log an early allocated block and populate the stack trace.
942 */
943static void early_alloc_percpu(struct early_log *log)
944{
945 unsigned int cpu;
946 const void __percpu *ptr = log->ptr;
947
948 for_each_possible_cpu(cpu) {
949 log->ptr = per_cpu_ptr(ptr, cpu);
950 early_alloc(log);
951 }
952}
953
954/**
955 * kmemleak_alloc - register a newly allocated object
956 * @ptr: pointer to beginning of the object
957 * @size: size of the object
958 * @min_count: minimum number of references to this object. If during memory
959 * scanning a number of references less than @min_count is found,
960 * the object is reported as a memory leak. If @min_count is 0,
961 * the object is never reported as a leak. If @min_count is -1,
962 * the object is ignored (not scanned and not reported as a leak)
963 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
964 *
965 * This function is called from the kernel allocators when a new object
966 * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
967 */
968void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
969 gfp_t gfp)
970{
971 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
972
973 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
974 create_object((unsigned long)ptr, size, min_count, gfp);
975 else if (kmemleak_early_log)
976 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
977}
978EXPORT_SYMBOL_GPL(kmemleak_alloc);
979
980/**
981 * kmemleak_alloc_percpu - register a newly allocated __percpu object
982 * @ptr: __percpu pointer to beginning of the object
983 * @size: size of the object
984 * @gfp: flags used for kmemleak internal memory allocations
985 *
986 * This function is called from the kernel percpu allocator when a new object
987 * (memory block) is allocated (alloc_percpu).
988 */
989void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
990 gfp_t gfp)
991{
992 unsigned int cpu;
993
994 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
995
996 /*
997 * Percpu allocations are only scanned and not reported as leaks
998 * (min_count is set to 0).
999 */
1000 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1001 for_each_possible_cpu(cpu)
1002 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
1003 size, 0, gfp);
1004 else if (kmemleak_early_log)
1005 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
1006}
1007EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
1008
1009/**
1010 * kmemleak_vmalloc - register a newly vmalloc'ed object
1011 * @area: pointer to vm_struct
1012 * @size: size of the object
1013 * @gfp: __vmalloc() flags used for kmemleak internal memory allocations
1014 *
1015 * This function is called from the vmalloc() kernel allocator when a new
1016 * object (memory block) is allocated.
1017 */
1018void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp)
1019{
1020 pr_debug("%s(0x%p, %zu)\n", __func__, area, size);
1021
1022 /*
1023 * A min_count = 2 is needed because vm_struct contains a reference to
1024 * the virtual address of the vmalloc'ed block.
1025 */
1026 if (kmemleak_enabled) {
1027 create_object((unsigned long)area->addr, size, 2, gfp);
1028 object_set_excess_ref((unsigned long)area,
1029 (unsigned long)area->addr);
1030 } else if (kmemleak_early_log) {
1031 log_early(KMEMLEAK_ALLOC, area->addr, size, 2);
1032 /* reusing early_log.size for storing area->addr */
1033 log_early(KMEMLEAK_SET_EXCESS_REF,
1034 area, (unsigned long)area->addr, 0);
1035 }
1036}
1037EXPORT_SYMBOL_GPL(kmemleak_vmalloc);
1038
1039/**
1040 * kmemleak_free - unregister a previously registered object
1041 * @ptr: pointer to beginning of the object
1042 *
1043 * This function is called from the kernel allocators when an object (memory
1044 * block) is freed (kmem_cache_free, kfree, vfree etc.).
1045 */
1046void __ref kmemleak_free(const void *ptr)
1047{
1048 pr_debug("%s(0x%p)\n", __func__, ptr);
1049
1050 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
1051 delete_object_full((unsigned long)ptr);
1052 else if (kmemleak_early_log)
1053 log_early(KMEMLEAK_FREE, ptr, 0, 0);
1054}
1055EXPORT_SYMBOL_GPL(kmemleak_free);
1056
1057/**
1058 * kmemleak_free_part - partially unregister a previously registered object
1059 * @ptr: pointer to the beginning or inside the object. This also
1060 * represents the start of the range to be freed
1061 * @size: size to be unregistered
1062 *
1063 * This function is called when only a part of a memory block is freed
1064 * (usually from the bootmem allocator).
1065 */
1066void __ref kmemleak_free_part(const void *ptr, size_t size)
1067{
1068 pr_debug("%s(0x%p)\n", __func__, ptr);
1069
1070 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1071 delete_object_part((unsigned long)ptr, size);
1072 else if (kmemleak_early_log)
1073 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
1074}
1075EXPORT_SYMBOL_GPL(kmemleak_free_part);
1076
1077/**
1078 * kmemleak_free_percpu - unregister a previously registered __percpu object
1079 * @ptr: __percpu pointer to beginning of the object
1080 *
1081 * This function is called from the kernel percpu allocator when an object
1082 * (memory block) is freed (free_percpu).
1083 */
1084void __ref kmemleak_free_percpu(const void __percpu *ptr)
1085{
1086 unsigned int cpu;
1087
1088 pr_debug("%s(0x%p)\n", __func__, ptr);
1089
1090 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
1091 for_each_possible_cpu(cpu)
1092 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1093 cpu));
1094 else if (kmemleak_early_log)
1095 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1096}
1097EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1098
1099/**
1100 * kmemleak_update_trace - update object allocation stack trace
1101 * @ptr: pointer to beginning of the object
1102 *
1103 * Override the object allocation stack trace for cases where the actual
1104 * allocation place is not always useful.
1105 */
1106void __ref kmemleak_update_trace(const void *ptr)
1107{
1108 struct kmemleak_object *object;
1109 unsigned long flags;
1110
1111 pr_debug("%s(0x%p)\n", __func__, ptr);
1112
1113 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1114 return;
1115
1116 object = find_and_get_object((unsigned long)ptr, 1);
1117 if (!object) {
1118#ifdef DEBUG
1119 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1120 ptr);
1121#endif
1122 return;
1123 }
1124
1125 spin_lock_irqsave(&object->lock, flags);
1126 object->trace_len = __save_stack_trace(object->trace);
1127 spin_unlock_irqrestore(&object->lock, flags);
1128
1129 put_object(object);
1130}
1131EXPORT_SYMBOL(kmemleak_update_trace);
1132
1133/**
1134 * kmemleak_not_leak - mark an allocated object as false positive
1135 * @ptr: pointer to beginning of the object
1136 *
1137 * Calling this function on an object will cause the memory block to no longer
1138 * be reported as leak and always be scanned.
1139 */
1140void __ref kmemleak_not_leak(const void *ptr)
1141{
1142 pr_debug("%s(0x%p)\n", __func__, ptr);
1143
1144 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1145 make_gray_object((unsigned long)ptr);
1146 else if (kmemleak_early_log)
1147 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
1148}
1149EXPORT_SYMBOL(kmemleak_not_leak);
1150
1151/**
1152 * kmemleak_ignore - ignore an allocated object
1153 * @ptr: pointer to beginning of the object
1154 *
1155 * Calling this function on an object will cause the memory block to be
1156 * ignored (not scanned and not reported as a leak). This is usually done when
1157 * it is known that the corresponding block is not a leak and does not contain
1158 * any references to other allocated memory blocks.
1159 */
1160void __ref kmemleak_ignore(const void *ptr)
1161{
1162 pr_debug("%s(0x%p)\n", __func__, ptr);
1163
1164 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1165 make_black_object((unsigned long)ptr);
1166 else if (kmemleak_early_log)
1167 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
1168}
1169EXPORT_SYMBOL(kmemleak_ignore);
1170
1171/**
1172 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1173 * @ptr: pointer to beginning or inside the object. This also
1174 * represents the start of the scan area
1175 * @size: size of the scan area
1176 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1177 *
1178 * This function is used when it is known that only certain parts of an object
1179 * contain references to other objects. Kmemleak will only scan these areas
1180 * reducing the number false negatives.
1181 */
1182void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
1183{
1184 pr_debug("%s(0x%p)\n", __func__, ptr);
1185
1186 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
1187 add_scan_area((unsigned long)ptr, size, gfp);
1188 else if (kmemleak_early_log)
1189 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
1190}
1191EXPORT_SYMBOL(kmemleak_scan_area);
1192
1193/**
1194 * kmemleak_no_scan - do not scan an allocated object
1195 * @ptr: pointer to beginning of the object
1196 *
1197 * This function notifies kmemleak not to scan the given memory block. Useful
1198 * in situations where it is known that the given object does not contain any
1199 * references to other objects. Kmemleak will not scan such objects reducing
1200 * the number of false negatives.
1201 */
1202void __ref kmemleak_no_scan(const void *ptr)
1203{
1204 pr_debug("%s(0x%p)\n", __func__, ptr);
1205
1206 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1207 object_no_scan((unsigned long)ptr);
1208 else if (kmemleak_early_log)
1209 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
1210}
1211EXPORT_SYMBOL(kmemleak_no_scan);
1212
1213/**
1214 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1215 * address argument
1216 * @phys: physical address of the object
1217 * @size: size of the object
1218 * @min_count: minimum number of references to this object.
1219 * See kmemleak_alloc()
1220 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1221 */
1222void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
1223 gfp_t gfp)
1224{
1225 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1226 kmemleak_alloc(__va(phys), size, min_count, gfp);
1227}
1228EXPORT_SYMBOL(kmemleak_alloc_phys);
1229
1230/**
1231 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1232 * physical address argument
1233 * @phys: physical address if the beginning or inside an object. This
1234 * also represents the start of the range to be freed
1235 * @size: size to be unregistered
1236 */
1237void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1238{
1239 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1240 kmemleak_free_part(__va(phys), size);
1241}
1242EXPORT_SYMBOL(kmemleak_free_part_phys);
1243
1244/**
1245 * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
1246 * address argument
1247 * @phys: physical address of the object
1248 */
1249void __ref kmemleak_not_leak_phys(phys_addr_t phys)
1250{
1251 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1252 kmemleak_not_leak(__va(phys));
1253}
1254EXPORT_SYMBOL(kmemleak_not_leak_phys);
1255
1256/**
1257 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1258 * address argument
1259 * @phys: physical address of the object
1260 */
1261void __ref kmemleak_ignore_phys(phys_addr_t phys)
1262{
1263 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1264 kmemleak_ignore(__va(phys));
1265}
1266EXPORT_SYMBOL(kmemleak_ignore_phys);
1267
1268/*
1269 * Update an object's checksum and return true if it was modified.
1270 */
1271static bool update_checksum(struct kmemleak_object *object)
1272{
1273 u32 old_csum = object->checksum;
1274
1275 kasan_disable_current();
1276 object->checksum = crc32(0, (void *)object->pointer, object->size);
1277 kasan_enable_current();
1278
1279 return object->checksum != old_csum;
1280}
1281
1282/*
1283 * Update an object's references. object->lock must be held by the caller.
1284 */
1285static void update_refs(struct kmemleak_object *object)
1286{
1287 if (!color_white(object)) {
1288 /* non-orphan, ignored or new */
1289 return;
1290 }
1291
1292 /*
1293 * Increase the object's reference count (number of pointers to the
1294 * memory block). If this count reaches the required minimum, the
1295 * object's color will become gray and it will be added to the
1296 * gray_list.
1297 */
1298 object->count++;
1299 if (color_gray(object)) {
1300 /* put_object() called when removing from gray_list */
1301 WARN_ON(!get_object(object));
1302 list_add_tail(&object->gray_list, &gray_list);
1303 }
1304}
1305
1306/*
1307 * Memory scanning is a long process and it needs to be interruptable. This
1308 * function checks whether such interrupt condition occurred.
1309 */
1310static int scan_should_stop(void)
1311{
1312 if (!kmemleak_enabled)
1313 return 1;
1314
1315 /*
1316 * This function may be called from either process or kthread context,
1317 * hence the need to check for both stop conditions.
1318 */
1319 if (current->mm)
1320 return signal_pending(current);
1321 else
1322 return kthread_should_stop();
1323
1324 return 0;
1325}
1326
1327/*
1328 * Scan a memory block (exclusive range) for valid pointers and add those
1329 * found to the gray list.
1330 */
1331static void scan_block(void *_start, void *_end,
1332 struct kmemleak_object *scanned)
1333{
1334 unsigned long *ptr;
1335 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1336 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
1337 unsigned long flags;
1338 unsigned long untagged_ptr;
1339
1340 read_lock_irqsave(&kmemleak_lock, flags);
1341 for (ptr = start; ptr < end; ptr++) {
1342 struct kmemleak_object *object;
1343 unsigned long pointer;
1344 unsigned long excess_ref;
1345
1346 if (scan_should_stop())
1347 break;
1348
1349 kasan_disable_current();
1350 pointer = *ptr;
1351 kasan_enable_current();
1352
1353 untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer);
1354 if (untagged_ptr < min_addr || untagged_ptr >= max_addr)
1355 continue;
1356
1357 /*
1358 * No need for get_object() here since we hold kmemleak_lock.
1359 * object->use_count cannot be dropped to 0 while the object
1360 * is still present in object_tree_root and object_list
1361 * (with updates protected by kmemleak_lock).
1362 */
1363 object = lookup_object(pointer, 1);
1364 if (!object)
1365 continue;
1366 if (object == scanned)
1367 /* self referenced, ignore */
1368 continue;
1369
1370 /*
1371 * Avoid the lockdep recursive warning on object->lock being
1372 * previously acquired in scan_object(). These locks are
1373 * enclosed by scan_mutex.
1374 */
1375 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
1376 /* only pass surplus references (object already gray) */
1377 if (color_gray(object)) {
1378 excess_ref = object->excess_ref;
1379 /* no need for update_refs() if object already gray */
1380 } else {
1381 excess_ref = 0;
1382 update_refs(object);
1383 }
1384 spin_unlock(&object->lock);
1385
1386 if (excess_ref) {
1387 object = lookup_object(excess_ref, 0);
1388 if (!object)
1389 continue;
1390 if (object == scanned)
1391 /* circular reference, ignore */
1392 continue;
1393 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
1394 update_refs(object);
1395 spin_unlock(&object->lock);
1396 }
1397 }
1398 read_unlock_irqrestore(&kmemleak_lock, flags);
1399}
1400
1401/*
1402 * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1403 */
1404static void scan_large_block(void *start, void *end)
1405{
1406 void *next;
1407
1408 while (start < end) {
1409 next = min(start + MAX_SCAN_SIZE, end);
1410 scan_block(start, next, NULL);
1411 start = next;
1412 cond_resched();
1413 }
1414}
1415
1416/*
1417 * Scan a memory block corresponding to a kmemleak_object. A condition is
1418 * that object->use_count >= 1.
1419 */
1420static void scan_object(struct kmemleak_object *object)
1421{
1422 struct kmemleak_scan_area *area;
1423 unsigned long flags;
1424
1425 /*
1426 * Once the object->lock is acquired, the corresponding memory block
1427 * cannot be freed (the same lock is acquired in delete_object).
1428 */
1429 spin_lock_irqsave(&object->lock, flags);
1430 if (object->flags & OBJECT_NO_SCAN)
1431 goto out;
1432 if (!(object->flags & OBJECT_ALLOCATED))
1433 /* already freed object */
1434 goto out;
1435 if (hlist_empty(&object->area_list)) {
1436 void *start = (void *)object->pointer;
1437 void *end = (void *)(object->pointer + object->size);
1438 void *next;
1439
1440 do {
1441 next = min(start + MAX_SCAN_SIZE, end);
1442 scan_block(start, next, object);
1443
1444 start = next;
1445 if (start >= end)
1446 break;
1447
1448 spin_unlock_irqrestore(&object->lock, flags);
1449 cond_resched();
1450 spin_lock_irqsave(&object->lock, flags);
1451 } while (object->flags & OBJECT_ALLOCATED);
1452 } else
1453 hlist_for_each_entry(area, &object->area_list, node)
1454 scan_block((void *)area->start,
1455 (void *)(area->start + area->size),
1456 object);
1457out:
1458 spin_unlock_irqrestore(&object->lock, flags);
1459}
1460
1461/*
1462 * Scan the objects already referenced (gray objects). More objects will be
1463 * referenced and, if there are no memory leaks, all the objects are scanned.
1464 */
1465static void scan_gray_list(void)
1466{
1467 struct kmemleak_object *object, *tmp;
1468
1469 /*
1470 * The list traversal is safe for both tail additions and removals
1471 * from inside the loop. The kmemleak objects cannot be freed from
1472 * outside the loop because their use_count was incremented.
1473 */
1474 object = list_entry(gray_list.next, typeof(*object), gray_list);
1475 while (&object->gray_list != &gray_list) {
1476 cond_resched();
1477
1478 /* may add new objects to the list */
1479 if (!scan_should_stop())
1480 scan_object(object);
1481
1482 tmp = list_entry(object->gray_list.next, typeof(*object),
1483 gray_list);
1484
1485 /* remove the object from the list and release it */
1486 list_del(&object->gray_list);
1487 put_object(object);
1488
1489 object = tmp;
1490 }
1491 WARN_ON(!list_empty(&gray_list));
1492}
1493
1494/*
1495 * Scan data sections and all the referenced memory blocks allocated via the
1496 * kernel's standard allocators. This function must be called with the
1497 * scan_mutex held.
1498 */
1499static void kmemleak_scan(void)
1500{
1501 unsigned long flags;
1502 struct kmemleak_object *object;
1503 int i;
1504 int new_leaks = 0;
1505
1506 jiffies_last_scan = jiffies;
1507
1508 /* prepare the kmemleak_object's */
1509 rcu_read_lock();
1510 list_for_each_entry_rcu(object, &object_list, object_list) {
1511 spin_lock_irqsave(&object->lock, flags);
1512#ifdef DEBUG
1513 /*
1514 * With a few exceptions there should be a maximum of
1515 * 1 reference to any object at this point.
1516 */
1517 if (atomic_read(&object->use_count) > 1) {
1518 pr_debug("object->use_count = %d\n",
1519 atomic_read(&object->use_count));
1520 dump_object_info(object);
1521 }
1522#endif
1523 /* reset the reference count (whiten the object) */
1524 object->count = 0;
1525 if (color_gray(object) && get_object(object))
1526 list_add_tail(&object->gray_list, &gray_list);
1527
1528 spin_unlock_irqrestore(&object->lock, flags);
1529 }
1530 rcu_read_unlock();
1531
1532 /* data/bss scanning */
1533 scan_large_block(_sdata, _edata);
1534 scan_large_block(__bss_start, __bss_stop);
1535 scan_large_block(__start_ro_after_init, __end_ro_after_init);
1536
1537#ifdef CONFIG_SMP
1538 /* per-cpu sections scanning */
1539 for_each_possible_cpu(i)
1540 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1541 __per_cpu_end + per_cpu_offset(i));
1542#endif
1543
1544 /*
1545 * Struct page scanning for each node.
1546 */
1547 get_online_mems();
1548 for_each_online_node(i) {
1549 unsigned long start_pfn = node_start_pfn(i);
1550 unsigned long end_pfn = node_end_pfn(i);
1551 unsigned long pfn;
1552
1553 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1554 struct page *page = pfn_to_online_page(pfn);
1555
1556 if (!page)
1557 continue;
1558
1559 /* only scan pages belonging to this node */
1560 if (page_to_nid(page) != i)
1561 continue;
1562 /* only scan if page is in use */
1563 if (page_count(page) == 0)
1564 continue;
1565 scan_block(page, page + 1, NULL);
1566 if (!(pfn & 63))
1567 cond_resched();
1568 }
1569 }
1570 put_online_mems();
1571
1572 /*
1573 * Scanning the task stacks (may introduce false negatives).
1574 */
1575 if (kmemleak_stack_scan) {
1576 struct task_struct *p, *g;
1577
1578 read_lock(&tasklist_lock);
1579 do_each_thread(g, p) {
1580 void *stack = try_get_task_stack(p);
1581 if (stack) {
1582 scan_block(stack, stack + THREAD_SIZE, NULL);
1583 put_task_stack(p);
1584 }
1585 } while_each_thread(g, p);
1586 read_unlock(&tasklist_lock);
1587 }
1588
1589 /*
1590 * Scan the objects already referenced from the sections scanned
1591 * above.
1592 */
1593 scan_gray_list();
1594
1595 /*
1596 * Check for new or unreferenced objects modified since the previous
1597 * scan and color them gray until the next scan.
1598 */
1599 rcu_read_lock();
1600 list_for_each_entry_rcu(object, &object_list, object_list) {
1601 spin_lock_irqsave(&object->lock, flags);
1602 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1603 && update_checksum(object) && get_object(object)) {
1604 /* color it gray temporarily */
1605 object->count = object->min_count;
1606 list_add_tail(&object->gray_list, &gray_list);
1607 }
1608 spin_unlock_irqrestore(&object->lock, flags);
1609 }
1610 rcu_read_unlock();
1611
1612 /*
1613 * Re-scan the gray list for modified unreferenced objects.
1614 */
1615 scan_gray_list();
1616
1617 /*
1618 * If scanning was stopped do not report any new unreferenced objects.
1619 */
1620 if (scan_should_stop())
1621 return;
1622
1623 /*
1624 * Scanning result reporting.
1625 */
1626 rcu_read_lock();
1627 list_for_each_entry_rcu(object, &object_list, object_list) {
1628 spin_lock_irqsave(&object->lock, flags);
1629 if (unreferenced_object(object) &&
1630 !(object->flags & OBJECT_REPORTED)) {
1631 object->flags |= OBJECT_REPORTED;
1632
1633 if (kmemleak_verbose)
1634 print_unreferenced(NULL, object);
1635
1636 new_leaks++;
1637 }
1638 spin_unlock_irqrestore(&object->lock, flags);
1639 }
1640 rcu_read_unlock();
1641
1642 if (new_leaks) {
1643 kmemleak_found_leaks = true;
1644
1645 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1646 new_leaks);
1647 }
1648
1649}
1650
1651/*
1652 * Thread function performing automatic memory scanning. Unreferenced objects
1653 * at the end of a memory scan are reported but only the first time.
1654 */
1655static int kmemleak_scan_thread(void *arg)
1656{
1657 static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN);
1658
1659 pr_info("Automatic memory scanning thread started\n");
1660 set_user_nice(current, 10);
1661
1662 /*
1663 * Wait before the first scan to allow the system to fully initialize.
1664 */
1665 if (first_run) {
1666 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
1667 first_run = 0;
1668 while (timeout && !kthread_should_stop())
1669 timeout = schedule_timeout_interruptible(timeout);
1670 }
1671
1672 while (!kthread_should_stop()) {
1673 signed long timeout = jiffies_scan_wait;
1674
1675 mutex_lock(&scan_mutex);
1676 kmemleak_scan();
1677 mutex_unlock(&scan_mutex);
1678
1679 /* wait before the next scan */
1680 while (timeout && !kthread_should_stop())
1681 timeout = schedule_timeout_interruptible(timeout);
1682 }
1683
1684 pr_info("Automatic memory scanning thread ended\n");
1685
1686 return 0;
1687}
1688
1689/*
1690 * Start the automatic memory scanning thread. This function must be called
1691 * with the scan_mutex held.
1692 */
1693static void start_scan_thread(void)
1694{
1695 if (scan_thread)
1696 return;
1697 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1698 if (IS_ERR(scan_thread)) {
1699 pr_warn("Failed to create the scan thread\n");
1700 scan_thread = NULL;
1701 }
1702}
1703
1704/*
1705 * Stop the automatic memory scanning thread.
1706 */
1707static void stop_scan_thread(void)
1708{
1709 if (scan_thread) {
1710 kthread_stop(scan_thread);
1711 scan_thread = NULL;
1712 }
1713}
1714
1715/*
1716 * Iterate over the object_list and return the first valid object at or after
1717 * the required position with its use_count incremented. The function triggers
1718 * a memory scanning when the pos argument points to the first position.
1719 */
1720static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1721{
1722 struct kmemleak_object *object;
1723 loff_t n = *pos;
1724 int err;
1725
1726 err = mutex_lock_interruptible(&scan_mutex);
1727 if (err < 0)
1728 return ERR_PTR(err);
1729
1730 rcu_read_lock();
1731 list_for_each_entry_rcu(object, &object_list, object_list) {
1732 if (n-- > 0)
1733 continue;
1734 if (get_object(object))
1735 goto out;
1736 }
1737 object = NULL;
1738out:
1739 return object;
1740}
1741
1742/*
1743 * Return the next object in the object_list. The function decrements the
1744 * use_count of the previous object and increases that of the next one.
1745 */
1746static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1747{
1748 struct kmemleak_object *prev_obj = v;
1749 struct kmemleak_object *next_obj = NULL;
1750 struct kmemleak_object *obj = prev_obj;
1751
1752 ++(*pos);
1753
1754 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
1755 if (get_object(obj)) {
1756 next_obj = obj;
1757 break;
1758 }
1759 }
1760
1761 put_object(prev_obj);
1762 return next_obj;
1763}
1764
1765/*
1766 * Decrement the use_count of the last object required, if any.
1767 */
1768static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1769{
1770 if (!IS_ERR(v)) {
1771 /*
1772 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1773 * waiting was interrupted, so only release it if !IS_ERR.
1774 */
1775 rcu_read_unlock();
1776 mutex_unlock(&scan_mutex);
1777 if (v)
1778 put_object(v);
1779 }
1780}
1781
1782/*
1783 * Print the information for an unreferenced object to the seq file.
1784 */
1785static int kmemleak_seq_show(struct seq_file *seq, void *v)
1786{
1787 struct kmemleak_object *object = v;
1788 unsigned long flags;
1789
1790 spin_lock_irqsave(&object->lock, flags);
1791 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
1792 print_unreferenced(seq, object);
1793 spin_unlock_irqrestore(&object->lock, flags);
1794 return 0;
1795}
1796
1797static const struct seq_operations kmemleak_seq_ops = {
1798 .start = kmemleak_seq_start,
1799 .next = kmemleak_seq_next,
1800 .stop = kmemleak_seq_stop,
1801 .show = kmemleak_seq_show,
1802};
1803
1804static int kmemleak_open(struct inode *inode, struct file *file)
1805{
1806 return seq_open(file, &kmemleak_seq_ops);
1807}
1808
1809static int dump_str_object_info(const char *str)
1810{
1811 unsigned long flags;
1812 struct kmemleak_object *object;
1813 unsigned long addr;
1814
1815 if (kstrtoul(str, 0, &addr))
1816 return -EINVAL;
1817 object = find_and_get_object(addr, 0);
1818 if (!object) {
1819 pr_info("Unknown object at 0x%08lx\n", addr);
1820 return -EINVAL;
1821 }
1822
1823 spin_lock_irqsave(&object->lock, flags);
1824 dump_object_info(object);
1825 spin_unlock_irqrestore(&object->lock, flags);
1826
1827 put_object(object);
1828 return 0;
1829}
1830
1831/*
1832 * We use grey instead of black to ensure we can do future scans on the same
1833 * objects. If we did not do future scans these black objects could
1834 * potentially contain references to newly allocated objects in the future and
1835 * we'd end up with false positives.
1836 */
1837static void kmemleak_clear(void)
1838{
1839 struct kmemleak_object *object;
1840 unsigned long flags;
1841
1842 rcu_read_lock();
1843 list_for_each_entry_rcu(object, &object_list, object_list) {
1844 spin_lock_irqsave(&object->lock, flags);
1845 if ((object->flags & OBJECT_REPORTED) &&
1846 unreferenced_object(object))
1847 __paint_it(object, KMEMLEAK_GREY);
1848 spin_unlock_irqrestore(&object->lock, flags);
1849 }
1850 rcu_read_unlock();
1851
1852 kmemleak_found_leaks = false;
1853}
1854
1855static void __kmemleak_do_cleanup(void);
1856
1857/*
1858 * File write operation to configure kmemleak at run-time. The following
1859 * commands can be written to the /sys/kernel/debug/kmemleak file:
1860 * off - disable kmemleak (irreversible)
1861 * stack=on - enable the task stacks scanning
1862 * stack=off - disable the tasks stacks scanning
1863 * scan=on - start the automatic memory scanning thread
1864 * scan=off - stop the automatic memory scanning thread
1865 * scan=... - set the automatic memory scanning period in seconds (0 to
1866 * disable it)
1867 * scan - trigger a memory scan
1868 * clear - mark all current reported unreferenced kmemleak objects as
1869 * grey to ignore printing them, or free all kmemleak objects
1870 * if kmemleak has been disabled.
1871 * dump=... - dump information about the object found at the given address
1872 */
1873static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1874 size_t size, loff_t *ppos)
1875{
1876 char buf[64];
1877 int buf_size;
1878 int ret;
1879
1880 buf_size = min(size, (sizeof(buf) - 1));
1881 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1882 return -EFAULT;
1883 buf[buf_size] = 0;
1884
1885 ret = mutex_lock_interruptible(&scan_mutex);
1886 if (ret < 0)
1887 return ret;
1888
1889 if (strncmp(buf, "clear", 5) == 0) {
1890 if (kmemleak_enabled)
1891 kmemleak_clear();
1892 else
1893 __kmemleak_do_cleanup();
1894 goto out;
1895 }
1896
1897 if (!kmemleak_enabled) {
1898 ret = -EBUSY;
1899 goto out;
1900 }
1901
1902 if (strncmp(buf, "off", 3) == 0)
1903 kmemleak_disable();
1904 else if (strncmp(buf, "stack=on", 8) == 0)
1905 kmemleak_stack_scan = 1;
1906 else if (strncmp(buf, "stack=off", 9) == 0)
1907 kmemleak_stack_scan = 0;
1908 else if (strncmp(buf, "scan=on", 7) == 0)
1909 start_scan_thread();
1910 else if (strncmp(buf, "scan=off", 8) == 0)
1911 stop_scan_thread();
1912 else if (strncmp(buf, "scan=", 5) == 0) {
1913 unsigned long secs;
1914
1915 ret = kstrtoul(buf + 5, 0, &secs);
1916 if (ret < 0)
1917 goto out;
1918 stop_scan_thread();
1919 if (secs) {
1920 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1921 start_scan_thread();
1922 }
1923 } else if (strncmp(buf, "scan", 4) == 0)
1924 kmemleak_scan();
1925 else if (strncmp(buf, "dump=", 5) == 0)
1926 ret = dump_str_object_info(buf + 5);
1927 else
1928 ret = -EINVAL;
1929
1930out:
1931 mutex_unlock(&scan_mutex);
1932 if (ret < 0)
1933 return ret;
1934
1935 /* ignore the rest of the buffer, only one command at a time */
1936 *ppos += size;
1937 return size;
1938}
1939
1940static const struct file_operations kmemleak_fops = {
1941 .owner = THIS_MODULE,
1942 .open = kmemleak_open,
1943 .read = seq_read,
1944 .write = kmemleak_write,
1945 .llseek = seq_lseek,
1946 .release = seq_release,
1947};
1948
1949static void __kmemleak_do_cleanup(void)
1950{
1951 struct kmemleak_object *object;
1952
1953 rcu_read_lock();
1954 list_for_each_entry_rcu(object, &object_list, object_list)
1955 delete_object_full(object->pointer);
1956 rcu_read_unlock();
1957}
1958
1959/*
1960 * Stop the memory scanning thread and free the kmemleak internal objects if
1961 * no previous scan thread (otherwise, kmemleak may still have some useful
1962 * information on memory leaks).
1963 */
1964static void kmemleak_do_cleanup(struct work_struct *work)
1965{
1966 stop_scan_thread();
1967
1968 mutex_lock(&scan_mutex);
1969 /*
1970 * Once it is made sure that kmemleak_scan has stopped, it is safe to no
1971 * longer track object freeing. Ordering of the scan thread stopping and
1972 * the memory accesses below is guaranteed by the kthread_stop()
1973 * function.
1974 */
1975 kmemleak_free_enabled = 0;
1976 mutex_unlock(&scan_mutex);
1977
1978 if (!kmemleak_found_leaks)
1979 __kmemleak_do_cleanup();
1980 else
1981 pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n");
1982}
1983
1984static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
1985
1986/*
1987 * Disable kmemleak. No memory allocation/freeing will be traced once this
1988 * function is called. Disabling kmemleak is an irreversible operation.
1989 */
1990static void kmemleak_disable(void)
1991{
1992 /* atomically check whether it was already invoked */
1993 if (cmpxchg(&kmemleak_error, 0, 1))
1994 return;
1995
1996 /* stop any memory operation tracing */
1997 kmemleak_enabled = 0;
1998
1999 /* check whether it is too early for a kernel thread */
2000 if (kmemleak_initialized)
2001 schedule_work(&cleanup_work);
2002 else
2003 kmemleak_free_enabled = 0;
2004
2005 pr_info("Kernel memory leak detector disabled\n");
2006}
2007
2008/*
2009 * Allow boot-time kmemleak disabling (enabled by default).
2010 */
2011static int __init kmemleak_boot_config(char *str)
2012{
2013 if (!str)
2014 return -EINVAL;
2015 if (strcmp(str, "off") == 0)
2016 kmemleak_disable();
2017 else if (strcmp(str, "on") == 0)
2018 kmemleak_skip_disable = 1;
2019 else
2020 return -EINVAL;
2021 return 0;
2022}
2023early_param("kmemleak", kmemleak_boot_config);
2024
2025static void __init print_log_trace(struct early_log *log)
2026{
2027 struct stack_trace trace;
2028
2029 trace.nr_entries = log->trace_len;
2030 trace.entries = log->trace;
2031
2032 pr_notice("Early log backtrace:\n");
2033 print_stack_trace(&trace, 2);
2034}
2035
2036/*
2037 * Kmemleak initialization.
2038 */
2039void __init kmemleak_init(void)
2040{
2041 int i;
2042 unsigned long flags;
2043
2044#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
2045 if (!kmemleak_skip_disable) {
2046 kmemleak_early_log = 0;
2047 kmemleak_disable();
2048 return;
2049 }
2050#endif
2051
2052 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
2053 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
2054
2055 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
2056 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
2057
2058 if (crt_early_log > ARRAY_SIZE(early_log))
2059 pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
2060 crt_early_log);
2061
2062 /* the kernel is still in UP mode, so disabling the IRQs is enough */
2063 local_irq_save(flags);
2064 kmemleak_early_log = 0;
2065 if (kmemleak_error) {
2066 local_irq_restore(flags);
2067 return;
2068 } else {
2069 kmemleak_enabled = 1;
2070 kmemleak_free_enabled = 1;
2071 }
2072 local_irq_restore(flags);
2073
2074 /*
2075 * This is the point where tracking allocations is safe. Automatic
2076 * scanning is started during the late initcall. Add the early logged
2077 * callbacks to the kmemleak infrastructure.
2078 */
2079 for (i = 0; i < crt_early_log; i++) {
2080 struct early_log *log = &early_log[i];
2081
2082 switch (log->op_type) {
2083 case KMEMLEAK_ALLOC:
2084 early_alloc(log);
2085 break;
2086 case KMEMLEAK_ALLOC_PERCPU:
2087 early_alloc_percpu(log);
2088 break;
2089 case KMEMLEAK_FREE:
2090 kmemleak_free(log->ptr);
2091 break;
2092 case KMEMLEAK_FREE_PART:
2093 kmemleak_free_part(log->ptr, log->size);
2094 break;
2095 case KMEMLEAK_FREE_PERCPU:
2096 kmemleak_free_percpu(log->ptr);
2097 break;
2098 case KMEMLEAK_NOT_LEAK:
2099 kmemleak_not_leak(log->ptr);
2100 break;
2101 case KMEMLEAK_IGNORE:
2102 kmemleak_ignore(log->ptr);
2103 break;
2104 case KMEMLEAK_SCAN_AREA:
2105 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
2106 break;
2107 case KMEMLEAK_NO_SCAN:
2108 kmemleak_no_scan(log->ptr);
2109 break;
2110 case KMEMLEAK_SET_EXCESS_REF:
2111 object_set_excess_ref((unsigned long)log->ptr,
2112 log->excess_ref);
2113 break;
2114 default:
2115 kmemleak_warn("Unknown early log operation: %d\n",
2116 log->op_type);
2117 }
2118
2119 if (kmemleak_warning) {
2120 print_log_trace(log);
2121 kmemleak_warning = 0;
2122 }
2123 }
2124}
2125
2126/*
2127 * Late initialization function.
2128 */
2129static int __init kmemleak_late_init(void)
2130{
2131 struct dentry *dentry;
2132
2133 kmemleak_initialized = 1;
2134
2135 dentry = debugfs_create_file("kmemleak", 0644, NULL, NULL,
2136 &kmemleak_fops);
2137 if (!dentry)
2138 pr_warn("Failed to create the debugfs kmemleak file\n");
2139
2140 if (kmemleak_error) {
2141 /*
2142 * Some error occurred and kmemleak was disabled. There is a
2143 * small chance that kmemleak_disable() was called immediately
2144 * after setting kmemleak_initialized and we may end up with
2145 * two clean-up threads but serialized by scan_mutex.
2146 */
2147 schedule_work(&cleanup_work);
2148 return -ENOMEM;
2149 }
2150
2151 if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) {
2152 mutex_lock(&scan_mutex);
2153 start_scan_thread();
2154 mutex_unlock(&scan_mutex);
2155 }
2156
2157 pr_info("Kernel memory leak detector initialized\n");
2158
2159 return 0;
2160}
2161late_initcall(kmemleak_late_init);
2162