Merge branch 'pm-pci'
[linux-2.6-microblaze.git] / mm / kmemleak.c
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/mutex.h>
90 #include <linux/rcupdate.h>
91 #include <linux/stacktrace.h>
92 #include <linux/cache.h>
93 #include <linux/percpu.h>
94 #include <linux/hardirq.h>
95 #include <linux/bootmem.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/kmemcheck.h>
114 #include <linux/kmemleak.h>
115 #include <linux/memory_hotplug.h>
116
117 /*
118  * Kmemleak configuration and common defines.
119  */
120 #define MAX_TRACE               16      /* stack trace length */
121 #define MSECS_MIN_AGE           5000    /* minimum object age for reporting */
122 #define SECS_FIRST_SCAN         60      /* delay before the first scan */
123 #define SECS_SCAN_WAIT          600     /* subsequent auto scanning delay */
124 #define MAX_SCAN_SIZE           4096    /* maximum size of a scanned block */
125
126 #define BYTES_PER_POINTER       sizeof(void *)
127
128 /* GFP bitmask for kmemleak internal allocations */
129 #define gfp_kmemleak_mask(gfp)  (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
130                                  __GFP_NORETRY | __GFP_NOMEMALLOC | \
131                                  __GFP_NOWARN)
132
133 /* scanning area inside a memory block */
134 struct kmemleak_scan_area {
135         struct hlist_node node;
136         unsigned long start;
137         size_t size;
138 };
139
140 #define KMEMLEAK_GREY   0
141 #define KMEMLEAK_BLACK  -1
142
143 /*
144  * Structure holding the metadata for each allocated memory block.
145  * Modifications to such objects should be made while holding the
146  * object->lock. Insertions or deletions from object_list, gray_list or
147  * rb_node are already protected by the corresponding locks or mutex (see
148  * the notes on locking above). These objects are reference-counted
149  * (use_count) and freed using the RCU mechanism.
150  */
151 struct kmemleak_object {
152         spinlock_t lock;
153         unsigned int flags;             /* object status flags */
154         struct list_head object_list;
155         struct list_head gray_list;
156         struct rb_node rb_node;
157         struct rcu_head rcu;            /* object_list lockless traversal */
158         /* object usage count; object freed when use_count == 0 */
159         atomic_t use_count;
160         unsigned long pointer;
161         size_t size;
162         /* pass surplus references to this pointer */
163         unsigned long excess_ref;
164         /* minimum number of a pointers found before it is considered leak */
165         int min_count;
166         /* the total number of pointers found pointing to this object */
167         int count;
168         /* checksum for detecting modified objects */
169         u32 checksum;
170         /* memory ranges to be scanned inside an object (empty for all) */
171         struct hlist_head area_list;
172         unsigned long trace[MAX_TRACE];
173         unsigned int trace_len;
174         unsigned long jiffies;          /* creation timestamp */
175         pid_t pid;                      /* pid of the current task */
176         char comm[TASK_COMM_LEN];       /* executable name */
177 };
178
179 /* flag representing the memory block allocation status */
180 #define OBJECT_ALLOCATED        (1 << 0)
181 /* flag set after the first reporting of an unreference object */
182 #define OBJECT_REPORTED         (1 << 1)
183 /* flag set to not scan the object */
184 #define OBJECT_NO_SCAN          (1 << 2)
185
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 */
196 static LIST_HEAD(object_list);
197 /* the list of gray-colored objects (see color_gray comment below) */
198 static LIST_HEAD(gray_list);
199 /* search tree for object boundaries */
200 static struct rb_root object_tree_root = RB_ROOT;
201 /* rw_lock protecting the access to object_list and object_tree_root */
202 static DEFINE_RWLOCK(kmemleak_lock);
203
204 /* allocation caches for kmemleak internal data */
205 static struct kmem_cache *object_cache;
206 static struct kmem_cache *scan_area_cache;
207
208 /* set if tracing memory operations is enabled */
209 static int kmemleak_enabled;
210 /* same as above but only for the kmemleak_free() callback */
211 static int kmemleak_free_enabled;
212 /* set in the late_initcall if there were no errors */
213 static int kmemleak_initialized;
214 /* enables or disables early logging of the memory operations */
215 static int kmemleak_early_log = 1;
216 /* set if a kmemleak warning was issued */
217 static int kmemleak_warning;
218 /* set if a fatal kmemleak error has occurred */
219 static int kmemleak_error;
220
221 /* minimum and maximum address that may be valid pointers */
222 static unsigned long min_addr = ULONG_MAX;
223 static unsigned long max_addr;
224
225 static struct task_struct *scan_thread;
226 /* used to avoid reporting of recently allocated objects */
227 static unsigned long jiffies_min_age;
228 static unsigned long jiffies_last_scan;
229 /* delay between automatic memory scannings */
230 static signed long jiffies_scan_wait;
231 /* enables or disables the task stacks scanning */
232 static int kmemleak_stack_scan = 1;
233 /* protects the memory scanning, parameters and debug/kmemleak file access */
234 static DEFINE_MUTEX(scan_mutex);
235 /* setting kmemleak=on, will set this var, skipping the disable */
236 static int kmemleak_skip_disable;
237 /* If there are leaks that can be reported */
238 static bool kmemleak_found_leaks;
239
240 /*
241  * Early object allocation/freeing logging. Kmemleak is initialized after the
242  * kernel allocator. However, both the kernel allocator and kmemleak may
243  * allocate memory blocks which need to be tracked. Kmemleak defines an
244  * arbitrary buffer to hold the allocation/freeing information before it is
245  * fully initialized.
246  */
247
248 /* kmemleak operation type for early logging */
249 enum {
250         KMEMLEAK_ALLOC,
251         KMEMLEAK_ALLOC_PERCPU,
252         KMEMLEAK_FREE,
253         KMEMLEAK_FREE_PART,
254         KMEMLEAK_FREE_PERCPU,
255         KMEMLEAK_NOT_LEAK,
256         KMEMLEAK_IGNORE,
257         KMEMLEAK_SCAN_AREA,
258         KMEMLEAK_NO_SCAN,
259         KMEMLEAK_SET_EXCESS_REF
260 };
261
262 /*
263  * Structure holding the information passed to kmemleak callbacks during the
264  * early logging.
265  */
266 struct early_log {
267         int op_type;                    /* kmemleak operation type */
268         int min_count;                  /* minimum reference count */
269         const void *ptr;                /* allocated/freed memory block */
270         union {
271                 size_t size;            /* memory block size */
272                 unsigned long excess_ref; /* surplus reference passing */
273         };
274         unsigned long trace[MAX_TRACE]; /* stack trace */
275         unsigned int trace_len;         /* stack trace length */
276 };
277
278 /* early logging buffer and current position */
279 static struct early_log
280         early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
281 static int crt_early_log __initdata;
282
283 static void kmemleak_disable(void);
284
285 /*
286  * Print a warning and dump the stack trace.
287  */
288 #define kmemleak_warn(x...)     do {            \
289         pr_warn(x);                             \
290         dump_stack();                           \
291         kmemleak_warning = 1;                   \
292 } while (0)
293
294 /*
295  * Macro invoked when a serious kmemleak condition occurred and cannot be
296  * recovered from. Kmemleak will be disabled and further allocation/freeing
297  * tracing no longer available.
298  */
299 #define kmemleak_stop(x...)     do {    \
300         kmemleak_warn(x);               \
301         kmemleak_disable();             \
302 } while (0)
303
304 /*
305  * Printing of the objects hex dump to the seq file. The number of lines to be
306  * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
307  * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
308  * with the object->lock held.
309  */
310 static void hex_dump_object(struct seq_file *seq,
311                             struct kmemleak_object *object)
312 {
313         const u8 *ptr = (const u8 *)object->pointer;
314         size_t len;
315
316         /* limit the number of lines to HEX_MAX_LINES */
317         len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
318
319         seq_printf(seq, "  hex dump (first %zu bytes):\n", len);
320         kasan_disable_current();
321         seq_hex_dump(seq, "    ", DUMP_PREFIX_NONE, HEX_ROW_SIZE,
322                      HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
323         kasan_enable_current();
324 }
325
326 /*
327  * Object colors, encoded with count and min_count:
328  * - white - orphan object, not enough references to it (count < min_count)
329  * - gray  - not orphan, not marked as false positive (min_count == 0) or
330  *              sufficient references to it (count >= min_count)
331  * - black - ignore, it doesn't contain references (e.g. text section)
332  *              (min_count == -1). No function defined for this color.
333  * Newly created objects don't have any color assigned (object->count == -1)
334  * before the next memory scan when they become white.
335  */
336 static bool color_white(const struct kmemleak_object *object)
337 {
338         return object->count != KMEMLEAK_BLACK &&
339                 object->count < object->min_count;
340 }
341
342 static bool color_gray(const struct kmemleak_object *object)
343 {
344         return object->min_count != KMEMLEAK_BLACK &&
345                 object->count >= object->min_count;
346 }
347
348 /*
349  * Objects are considered unreferenced only if their color is white, they have
350  * not be deleted and have a minimum age to avoid false positives caused by
351  * pointers temporarily stored in CPU registers.
352  */
353 static bool unreferenced_object(struct kmemleak_object *object)
354 {
355         return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
356                 time_before_eq(object->jiffies + jiffies_min_age,
357                                jiffies_last_scan);
358 }
359
360 /*
361  * Printing of the unreferenced objects information to the seq file. The
362  * print_unreferenced function must be called with the object->lock held.
363  */
364 static void print_unreferenced(struct seq_file *seq,
365                                struct kmemleak_object *object)
366 {
367         int i;
368         unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
369
370         seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
371                    object->pointer, object->size);
372         seq_printf(seq, "  comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
373                    object->comm, object->pid, object->jiffies,
374                    msecs_age / 1000, msecs_age % 1000);
375         hex_dump_object(seq, object);
376         seq_printf(seq, "  backtrace:\n");
377
378         for (i = 0; i < object->trace_len; i++) {
379                 void *ptr = (void *)object->trace[i];
380                 seq_printf(seq, "    [<%p>] %pS\n", ptr, ptr);
381         }
382 }
383
384 /*
385  * Print the kmemleak_object information. This function is used mainly for
386  * debugging special cases when kmemleak operations. It must be called with
387  * the object->lock held.
388  */
389 static void dump_object_info(struct kmemleak_object *object)
390 {
391         struct stack_trace trace;
392
393         trace.nr_entries = object->trace_len;
394         trace.entries = object->trace;
395
396         pr_notice("Object 0x%08lx (size %zu):\n",
397                   object->pointer, object->size);
398         pr_notice("  comm \"%s\", pid %d, jiffies %lu\n",
399                   object->comm, object->pid, object->jiffies);
400         pr_notice("  min_count = %d\n", object->min_count);
401         pr_notice("  count = %d\n", object->count);
402         pr_notice("  flags = 0x%x\n", object->flags);
403         pr_notice("  checksum = %u\n", object->checksum);
404         pr_notice("  backtrace:\n");
405         print_stack_trace(&trace, 4);
406 }
407
408 /*
409  * Look-up a memory block metadata (kmemleak_object) in the object search
410  * tree based on a pointer value. If alias is 0, only values pointing to the
411  * beginning of the memory block are allowed. The kmemleak_lock must be held
412  * when calling this function.
413  */
414 static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
415 {
416         struct rb_node *rb = object_tree_root.rb_node;
417
418         while (rb) {
419                 struct kmemleak_object *object =
420                         rb_entry(rb, struct kmemleak_object, rb_node);
421                 if (ptr < object->pointer)
422                         rb = object->rb_node.rb_left;
423                 else if (object->pointer + object->size <= ptr)
424                         rb = object->rb_node.rb_right;
425                 else if (object->pointer == ptr || alias)
426                         return object;
427                 else {
428                         kmemleak_warn("Found object by alias at 0x%08lx\n",
429                                       ptr);
430                         dump_object_info(object);
431                         break;
432                 }
433         }
434         return NULL;
435 }
436
437 /*
438  * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
439  * that once an object's use_count reached 0, the RCU freeing was already
440  * registered and the object should no longer be used. This function must be
441  * called under the protection of rcu_read_lock().
442  */
443 static int get_object(struct kmemleak_object *object)
444 {
445         return atomic_inc_not_zero(&object->use_count);
446 }
447
448 /*
449  * RCU callback to free a kmemleak_object.
450  */
451 static void free_object_rcu(struct rcu_head *rcu)
452 {
453         struct hlist_node *tmp;
454         struct kmemleak_scan_area *area;
455         struct kmemleak_object *object =
456                 container_of(rcu, struct kmemleak_object, rcu);
457
458         /*
459          * Once use_count is 0 (guaranteed by put_object), there is no other
460          * code accessing this object, hence no need for locking.
461          */
462         hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
463                 hlist_del(&area->node);
464                 kmem_cache_free(scan_area_cache, area);
465         }
466         kmem_cache_free(object_cache, object);
467 }
468
469 /*
470  * Decrement the object use_count. Once the count is 0, free the object using
471  * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
472  * delete_object() path, the delayed RCU freeing ensures that there is no
473  * recursive call to the kernel allocator. Lock-less RCU object_list traversal
474  * is also possible.
475  */
476 static void put_object(struct kmemleak_object *object)
477 {
478         if (!atomic_dec_and_test(&object->use_count))
479                 return;
480
481         /* should only get here after delete_object was called */
482         WARN_ON(object->flags & OBJECT_ALLOCATED);
483
484         call_rcu(&object->rcu, free_object_rcu);
485 }
486
487 /*
488  * Look up an object in the object search tree and increase its use_count.
489  */
490 static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
491 {
492         unsigned long flags;
493         struct kmemleak_object *object;
494
495         rcu_read_lock();
496         read_lock_irqsave(&kmemleak_lock, flags);
497         object = lookup_object(ptr, alias);
498         read_unlock_irqrestore(&kmemleak_lock, flags);
499
500         /* check whether the object is still available */
501         if (object && !get_object(object))
502                 object = NULL;
503         rcu_read_unlock();
504
505         return object;
506 }
507
508 /*
509  * Look up an object in the object search tree and remove it from both
510  * object_tree_root and object_list. The returned object's use_count should be
511  * at least 1, as initially set by create_object().
512  */
513 static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
514 {
515         unsigned long flags;
516         struct kmemleak_object *object;
517
518         write_lock_irqsave(&kmemleak_lock, flags);
519         object = lookup_object(ptr, alias);
520         if (object) {
521                 rb_erase(&object->rb_node, &object_tree_root);
522                 list_del_rcu(&object->object_list);
523         }
524         write_unlock_irqrestore(&kmemleak_lock, flags);
525
526         return object;
527 }
528
529 /*
530  * Save stack trace to the given array of MAX_TRACE size.
531  */
532 static int __save_stack_trace(unsigned long *trace)
533 {
534         struct stack_trace stack_trace;
535
536         stack_trace.max_entries = MAX_TRACE;
537         stack_trace.nr_entries = 0;
538         stack_trace.entries = trace;
539         stack_trace.skip = 2;
540         save_stack_trace(&stack_trace);
541
542         return stack_trace.nr_entries;
543 }
544
545 /*
546  * Create the metadata (struct kmemleak_object) corresponding to an allocated
547  * memory block and add it to the object_list and object_tree_root.
548  */
549 static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
550                                              int min_count, gfp_t gfp)
551 {
552         unsigned long flags;
553         struct kmemleak_object *object, *parent;
554         struct rb_node **link, *rb_parent;
555
556         object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
557         if (!object) {
558                 pr_warn("Cannot allocate a kmemleak_object structure\n");
559                 kmemleak_disable();
560                 return NULL;
561         }
562
563         INIT_LIST_HEAD(&object->object_list);
564         INIT_LIST_HEAD(&object->gray_list);
565         INIT_HLIST_HEAD(&object->area_list);
566         spin_lock_init(&object->lock);
567         atomic_set(&object->use_count, 1);
568         object->flags = OBJECT_ALLOCATED;
569         object->pointer = ptr;
570         object->size = size;
571         object->excess_ref = 0;
572         object->min_count = min_count;
573         object->count = 0;                      /* white color initially */
574         object->jiffies = jiffies;
575         object->checksum = 0;
576
577         /* task information */
578         if (in_irq()) {
579                 object->pid = 0;
580                 strncpy(object->comm, "hardirq", sizeof(object->comm));
581         } else if (in_softirq()) {
582                 object->pid = 0;
583                 strncpy(object->comm, "softirq", sizeof(object->comm));
584         } else {
585                 object->pid = current->pid;
586                 /*
587                  * There is a small chance of a race with set_task_comm(),
588                  * however using get_task_comm() here may cause locking
589                  * dependency issues with current->alloc_lock. In the worst
590                  * case, the command line is not correct.
591                  */
592                 strncpy(object->comm, current->comm, sizeof(object->comm));
593         }
594
595         /* kernel backtrace */
596         object->trace_len = __save_stack_trace(object->trace);
597
598         write_lock_irqsave(&kmemleak_lock, flags);
599
600         min_addr = min(min_addr, ptr);
601         max_addr = max(max_addr, ptr + size);
602         link = &object_tree_root.rb_node;
603         rb_parent = NULL;
604         while (*link) {
605                 rb_parent = *link;
606                 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
607                 if (ptr + size <= parent->pointer)
608                         link = &parent->rb_node.rb_left;
609                 else if (parent->pointer + parent->size <= ptr)
610                         link = &parent->rb_node.rb_right;
611                 else {
612                         kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
613                                       ptr);
614                         /*
615                          * No need for parent->lock here since "parent" cannot
616                          * be freed while the kmemleak_lock is held.
617                          */
618                         dump_object_info(parent);
619                         kmem_cache_free(object_cache, object);
620                         object = NULL;
621                         goto out;
622                 }
623         }
624         rb_link_node(&object->rb_node, rb_parent, link);
625         rb_insert_color(&object->rb_node, &object_tree_root);
626
627         list_add_tail_rcu(&object->object_list, &object_list);
628 out:
629         write_unlock_irqrestore(&kmemleak_lock, flags);
630         return object;
631 }
632
633 /*
634  * Mark the object as not allocated and schedule RCU freeing via put_object().
635  */
636 static void __delete_object(struct kmemleak_object *object)
637 {
638         unsigned long flags;
639
640         WARN_ON(!(object->flags & OBJECT_ALLOCATED));
641         WARN_ON(atomic_read(&object->use_count) < 1);
642
643         /*
644          * Locking here also ensures that the corresponding memory block
645          * cannot be freed when it is being scanned.
646          */
647         spin_lock_irqsave(&object->lock, flags);
648         object->flags &= ~OBJECT_ALLOCATED;
649         spin_unlock_irqrestore(&object->lock, flags);
650         put_object(object);
651 }
652
653 /*
654  * Look up the metadata (struct kmemleak_object) corresponding to ptr and
655  * delete it.
656  */
657 static void delete_object_full(unsigned long ptr)
658 {
659         struct kmemleak_object *object;
660
661         object = find_and_remove_object(ptr, 0);
662         if (!object) {
663 #ifdef DEBUG
664                 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
665                               ptr);
666 #endif
667                 return;
668         }
669         __delete_object(object);
670 }
671
672 /*
673  * Look up the metadata (struct kmemleak_object) corresponding to ptr and
674  * delete it. If the memory block is partially freed, the function may create
675  * additional metadata for the remaining parts of the block.
676  */
677 static void delete_object_part(unsigned long ptr, size_t size)
678 {
679         struct kmemleak_object *object;
680         unsigned long start, end;
681
682         object = find_and_remove_object(ptr, 1);
683         if (!object) {
684 #ifdef DEBUG
685                 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
686                               ptr, size);
687 #endif
688                 return;
689         }
690
691         /*
692          * Create one or two objects that may result from the memory block
693          * split. Note that partial freeing is only done by free_bootmem() and
694          * this happens before kmemleak_init() is called. The path below is
695          * only executed during early log recording in kmemleak_init(), so
696          * GFP_KERNEL is enough.
697          */
698         start = object->pointer;
699         end = object->pointer + object->size;
700         if (ptr > start)
701                 create_object(start, ptr - start, object->min_count,
702                               GFP_KERNEL);
703         if (ptr + size < end)
704                 create_object(ptr + size, end - ptr - size, object->min_count,
705                               GFP_KERNEL);
706
707         __delete_object(object);
708 }
709
710 static void __paint_it(struct kmemleak_object *object, int color)
711 {
712         object->min_count = color;
713         if (color == KMEMLEAK_BLACK)
714                 object->flags |= OBJECT_NO_SCAN;
715 }
716
717 static void paint_it(struct kmemleak_object *object, int color)
718 {
719         unsigned long flags;
720
721         spin_lock_irqsave(&object->lock, flags);
722         __paint_it(object, color);
723         spin_unlock_irqrestore(&object->lock, flags);
724 }
725
726 static void paint_ptr(unsigned long ptr, int color)
727 {
728         struct kmemleak_object *object;
729
730         object = find_and_get_object(ptr, 0);
731         if (!object) {
732                 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
733                               ptr,
734                               (color == KMEMLEAK_GREY) ? "Grey" :
735                               (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
736                 return;
737         }
738         paint_it(object, color);
739         put_object(object);
740 }
741
742 /*
743  * Mark an object permanently as gray-colored so that it can no longer be
744  * reported as a leak. This is used in general to mark a false positive.
745  */
746 static void make_gray_object(unsigned long ptr)
747 {
748         paint_ptr(ptr, KMEMLEAK_GREY);
749 }
750
751 /*
752  * Mark the object as black-colored so that it is ignored from scans and
753  * reporting.
754  */
755 static void make_black_object(unsigned long ptr)
756 {
757         paint_ptr(ptr, KMEMLEAK_BLACK);
758 }
759
760 /*
761  * Add a scanning area to the object. If at least one such area is added,
762  * kmemleak will only scan these ranges rather than the whole memory block.
763  */
764 static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
765 {
766         unsigned long flags;
767         struct kmemleak_object *object;
768         struct kmemleak_scan_area *area;
769
770         object = find_and_get_object(ptr, 1);
771         if (!object) {
772                 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
773                               ptr);
774                 return;
775         }
776
777         area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
778         if (!area) {
779                 pr_warn("Cannot allocate a scan area\n");
780                 goto out;
781         }
782
783         spin_lock_irqsave(&object->lock, flags);
784         if (size == SIZE_MAX) {
785                 size = object->pointer + object->size - ptr;
786         } else if (ptr + size > object->pointer + object->size) {
787                 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
788                 dump_object_info(object);
789                 kmem_cache_free(scan_area_cache, area);
790                 goto out_unlock;
791         }
792
793         INIT_HLIST_NODE(&area->node);
794         area->start = ptr;
795         area->size = size;
796
797         hlist_add_head(&area->node, &object->area_list);
798 out_unlock:
799         spin_unlock_irqrestore(&object->lock, flags);
800 out:
801         put_object(object);
802 }
803
804 /*
805  * Any surplus references (object already gray) to 'ptr' are passed to
806  * 'excess_ref'. This is used in the vmalloc() case where a pointer to
807  * vm_struct may be used as an alternative reference to the vmalloc'ed object
808  * (see free_thread_stack()).
809  */
810 static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
811 {
812         unsigned long flags;
813         struct kmemleak_object *object;
814
815         object = find_and_get_object(ptr, 0);
816         if (!object) {
817                 kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
818                               ptr);
819                 return;
820         }
821
822         spin_lock_irqsave(&object->lock, flags);
823         object->excess_ref = excess_ref;
824         spin_unlock_irqrestore(&object->lock, flags);
825         put_object(object);
826 }
827
828 /*
829  * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
830  * pointer. Such object will not be scanned by kmemleak but references to it
831  * are searched.
832  */
833 static void object_no_scan(unsigned long ptr)
834 {
835         unsigned long flags;
836         struct kmemleak_object *object;
837
838         object = find_and_get_object(ptr, 0);
839         if (!object) {
840                 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
841                 return;
842         }
843
844         spin_lock_irqsave(&object->lock, flags);
845         object->flags |= OBJECT_NO_SCAN;
846         spin_unlock_irqrestore(&object->lock, flags);
847         put_object(object);
848 }
849
850 /*
851  * Log an early kmemleak_* call to the early_log buffer. These calls will be
852  * processed later once kmemleak is fully initialized.
853  */
854 static void __init log_early(int op_type, const void *ptr, size_t size,
855                              int min_count)
856 {
857         unsigned long flags;
858         struct early_log *log;
859
860         if (kmemleak_error) {
861                 /* kmemleak stopped recording, just count the requests */
862                 crt_early_log++;
863                 return;
864         }
865
866         if (crt_early_log >= ARRAY_SIZE(early_log)) {
867                 crt_early_log++;
868                 kmemleak_disable();
869                 return;
870         }
871
872         /*
873          * There is no need for locking since the kernel is still in UP mode
874          * at this stage. Disabling the IRQs is enough.
875          */
876         local_irq_save(flags);
877         log = &early_log[crt_early_log];
878         log->op_type = op_type;
879         log->ptr = ptr;
880         log->size = size;
881         log->min_count = min_count;
882         log->trace_len = __save_stack_trace(log->trace);
883         crt_early_log++;
884         local_irq_restore(flags);
885 }
886
887 /*
888  * Log an early allocated block and populate the stack trace.
889  */
890 static void early_alloc(struct early_log *log)
891 {
892         struct kmemleak_object *object;
893         unsigned long flags;
894         int i;
895
896         if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
897                 return;
898
899         /*
900          * RCU locking needed to ensure object is not freed via put_object().
901          */
902         rcu_read_lock();
903         object = create_object((unsigned long)log->ptr, log->size,
904                                log->min_count, GFP_ATOMIC);
905         if (!object)
906                 goto out;
907         spin_lock_irqsave(&object->lock, flags);
908         for (i = 0; i < log->trace_len; i++)
909                 object->trace[i] = log->trace[i];
910         object->trace_len = log->trace_len;
911         spin_unlock_irqrestore(&object->lock, flags);
912 out:
913         rcu_read_unlock();
914 }
915
916 /*
917  * Log an early allocated block and populate the stack trace.
918  */
919 static void early_alloc_percpu(struct early_log *log)
920 {
921         unsigned int cpu;
922         const void __percpu *ptr = log->ptr;
923
924         for_each_possible_cpu(cpu) {
925                 log->ptr = per_cpu_ptr(ptr, cpu);
926                 early_alloc(log);
927         }
928 }
929
930 /**
931  * kmemleak_alloc - register a newly allocated object
932  * @ptr:        pointer to beginning of the object
933  * @size:       size of the object
934  * @min_count:  minimum number of references to this object. If during memory
935  *              scanning a number of references less than @min_count is found,
936  *              the object is reported as a memory leak. If @min_count is 0,
937  *              the object is never reported as a leak. If @min_count is -1,
938  *              the object is ignored (not scanned and not reported as a leak)
939  * @gfp:        kmalloc() flags used for kmemleak internal memory allocations
940  *
941  * This function is called from the kernel allocators when a new object
942  * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
943  */
944 void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
945                           gfp_t gfp)
946 {
947         pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
948
949         if (kmemleak_enabled && ptr && !IS_ERR(ptr))
950                 create_object((unsigned long)ptr, size, min_count, gfp);
951         else if (kmemleak_early_log)
952                 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
953 }
954 EXPORT_SYMBOL_GPL(kmemleak_alloc);
955
956 /**
957  * kmemleak_alloc_percpu - register a newly allocated __percpu object
958  * @ptr:        __percpu pointer to beginning of the object
959  * @size:       size of the object
960  * @gfp:        flags used for kmemleak internal memory allocations
961  *
962  * This function is called from the kernel percpu allocator when a new object
963  * (memory block) is allocated (alloc_percpu).
964  */
965 void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
966                                  gfp_t gfp)
967 {
968         unsigned int cpu;
969
970         pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
971
972         /*
973          * Percpu allocations are only scanned and not reported as leaks
974          * (min_count is set to 0).
975          */
976         if (kmemleak_enabled && ptr && !IS_ERR(ptr))
977                 for_each_possible_cpu(cpu)
978                         create_object((unsigned long)per_cpu_ptr(ptr, cpu),
979                                       size, 0, gfp);
980         else if (kmemleak_early_log)
981                 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
982 }
983 EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
984
985 /**
986  * kmemleak_vmalloc - register a newly vmalloc'ed object
987  * @area:       pointer to vm_struct
988  * @size:       size of the object
989  * @gfp:        __vmalloc() flags used for kmemleak internal memory allocations
990  *
991  * This function is called from the vmalloc() kernel allocator when a new
992  * object (memory block) is allocated.
993  */
994 void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp)
995 {
996         pr_debug("%s(0x%p, %zu)\n", __func__, area, size);
997
998         /*
999          * A min_count = 2 is needed because vm_struct contains a reference to
1000          * the virtual address of the vmalloc'ed block.
1001          */
1002         if (kmemleak_enabled) {
1003                 create_object((unsigned long)area->addr, size, 2, gfp);
1004                 object_set_excess_ref((unsigned long)area,
1005                                       (unsigned long)area->addr);
1006         } else if (kmemleak_early_log) {
1007                 log_early(KMEMLEAK_ALLOC, area->addr, size, 2);
1008                 /* reusing early_log.size for storing area->addr */
1009                 log_early(KMEMLEAK_SET_EXCESS_REF,
1010                           area, (unsigned long)area->addr, 0);
1011         }
1012 }
1013 EXPORT_SYMBOL_GPL(kmemleak_vmalloc);
1014
1015 /**
1016  * kmemleak_free - unregister a previously registered object
1017  * @ptr:        pointer to beginning of the object
1018  *
1019  * This function is called from the kernel allocators when an object (memory
1020  * block) is freed (kmem_cache_free, kfree, vfree etc.).
1021  */
1022 void __ref kmemleak_free(const void *ptr)
1023 {
1024         pr_debug("%s(0x%p)\n", __func__, ptr);
1025
1026         if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
1027                 delete_object_full((unsigned long)ptr);
1028         else if (kmemleak_early_log)
1029                 log_early(KMEMLEAK_FREE, ptr, 0, 0);
1030 }
1031 EXPORT_SYMBOL_GPL(kmemleak_free);
1032
1033 /**
1034  * kmemleak_free_part - partially unregister a previously registered object
1035  * @ptr:        pointer to the beginning or inside the object. This also
1036  *              represents the start of the range to be freed
1037  * @size:       size to be unregistered
1038  *
1039  * This function is called when only a part of a memory block is freed
1040  * (usually from the bootmem allocator).
1041  */
1042 void __ref kmemleak_free_part(const void *ptr, size_t size)
1043 {
1044         pr_debug("%s(0x%p)\n", __func__, ptr);
1045
1046         if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1047                 delete_object_part((unsigned long)ptr, size);
1048         else if (kmemleak_early_log)
1049                 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
1050 }
1051 EXPORT_SYMBOL_GPL(kmemleak_free_part);
1052
1053 /**
1054  * kmemleak_free_percpu - unregister a previously registered __percpu object
1055  * @ptr:        __percpu pointer to beginning of the object
1056  *
1057  * This function is called from the kernel percpu allocator when an object
1058  * (memory block) is freed (free_percpu).
1059  */
1060 void __ref kmemleak_free_percpu(const void __percpu *ptr)
1061 {
1062         unsigned int cpu;
1063
1064         pr_debug("%s(0x%p)\n", __func__, ptr);
1065
1066         if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
1067                 for_each_possible_cpu(cpu)
1068                         delete_object_full((unsigned long)per_cpu_ptr(ptr,
1069                                                                       cpu));
1070         else if (kmemleak_early_log)
1071                 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1072 }
1073 EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1074
1075 /**
1076  * kmemleak_update_trace - update object allocation stack trace
1077  * @ptr:        pointer to beginning of the object
1078  *
1079  * Override the object allocation stack trace for cases where the actual
1080  * allocation place is not always useful.
1081  */
1082 void __ref kmemleak_update_trace(const void *ptr)
1083 {
1084         struct kmemleak_object *object;
1085         unsigned long flags;
1086
1087         pr_debug("%s(0x%p)\n", __func__, ptr);
1088
1089         if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1090                 return;
1091
1092         object = find_and_get_object((unsigned long)ptr, 1);
1093         if (!object) {
1094 #ifdef DEBUG
1095                 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1096                               ptr);
1097 #endif
1098                 return;
1099         }
1100
1101         spin_lock_irqsave(&object->lock, flags);
1102         object->trace_len = __save_stack_trace(object->trace);
1103         spin_unlock_irqrestore(&object->lock, flags);
1104
1105         put_object(object);
1106 }
1107 EXPORT_SYMBOL(kmemleak_update_trace);
1108
1109 /**
1110  * kmemleak_not_leak - mark an allocated object as false positive
1111  * @ptr:        pointer to beginning of the object
1112  *
1113  * Calling this function on an object will cause the memory block to no longer
1114  * be reported as leak and always be scanned.
1115  */
1116 void __ref kmemleak_not_leak(const void *ptr)
1117 {
1118         pr_debug("%s(0x%p)\n", __func__, ptr);
1119
1120         if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1121                 make_gray_object((unsigned long)ptr);
1122         else if (kmemleak_early_log)
1123                 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
1124 }
1125 EXPORT_SYMBOL(kmemleak_not_leak);
1126
1127 /**
1128  * kmemleak_ignore - ignore an allocated object
1129  * @ptr:        pointer to beginning of the object
1130  *
1131  * Calling this function on an object will cause the memory block to be
1132  * ignored (not scanned and not reported as a leak). This is usually done when
1133  * it is known that the corresponding block is not a leak and does not contain
1134  * any references to other allocated memory blocks.
1135  */
1136 void __ref kmemleak_ignore(const void *ptr)
1137 {
1138         pr_debug("%s(0x%p)\n", __func__, ptr);
1139
1140         if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1141                 make_black_object((unsigned long)ptr);
1142         else if (kmemleak_early_log)
1143                 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
1144 }
1145 EXPORT_SYMBOL(kmemleak_ignore);
1146
1147 /**
1148  * kmemleak_scan_area - limit the range to be scanned in an allocated object
1149  * @ptr:        pointer to beginning or inside the object. This also
1150  *              represents the start of the scan area
1151  * @size:       size of the scan area
1152  * @gfp:        kmalloc() flags used for kmemleak internal memory allocations
1153  *
1154  * This function is used when it is known that only certain parts of an object
1155  * contain references to other objects. Kmemleak will only scan these areas
1156  * reducing the number false negatives.
1157  */
1158 void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
1159 {
1160         pr_debug("%s(0x%p)\n", __func__, ptr);
1161
1162         if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
1163                 add_scan_area((unsigned long)ptr, size, gfp);
1164         else if (kmemleak_early_log)
1165                 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
1166 }
1167 EXPORT_SYMBOL(kmemleak_scan_area);
1168
1169 /**
1170  * kmemleak_no_scan - do not scan an allocated object
1171  * @ptr:        pointer to beginning of the object
1172  *
1173  * This function notifies kmemleak not to scan the given memory block. Useful
1174  * in situations where it is known that the given object does not contain any
1175  * references to other objects. Kmemleak will not scan such objects reducing
1176  * the number of false negatives.
1177  */
1178 void __ref kmemleak_no_scan(const void *ptr)
1179 {
1180         pr_debug("%s(0x%p)\n", __func__, ptr);
1181
1182         if (kmemleak_enabled && ptr && !IS_ERR(ptr))
1183                 object_no_scan((unsigned long)ptr);
1184         else if (kmemleak_early_log)
1185                 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
1186 }
1187 EXPORT_SYMBOL(kmemleak_no_scan);
1188
1189 /**
1190  * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1191  *                       address argument
1192  */
1193 void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
1194                                gfp_t gfp)
1195 {
1196         if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1197                 kmemleak_alloc(__va(phys), size, min_count, gfp);
1198 }
1199 EXPORT_SYMBOL(kmemleak_alloc_phys);
1200
1201 /**
1202  * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1203  *                           physical address argument
1204  */
1205 void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1206 {
1207         if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1208                 kmemleak_free_part(__va(phys), size);
1209 }
1210 EXPORT_SYMBOL(kmemleak_free_part_phys);
1211
1212 /**
1213  * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
1214  *                          address argument
1215  */
1216 void __ref kmemleak_not_leak_phys(phys_addr_t phys)
1217 {
1218         if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1219                 kmemleak_not_leak(__va(phys));
1220 }
1221 EXPORT_SYMBOL(kmemleak_not_leak_phys);
1222
1223 /**
1224  * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1225  *                        address argument
1226  */
1227 void __ref kmemleak_ignore_phys(phys_addr_t phys)
1228 {
1229         if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1230                 kmemleak_ignore(__va(phys));
1231 }
1232 EXPORT_SYMBOL(kmemleak_ignore_phys);
1233
1234 /*
1235  * Update an object's checksum and return true if it was modified.
1236  */
1237 static bool update_checksum(struct kmemleak_object *object)
1238 {
1239         u32 old_csum = object->checksum;
1240
1241         if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
1242                 return false;
1243
1244         kasan_disable_current();
1245         object->checksum = crc32(0, (void *)object->pointer, object->size);
1246         kasan_enable_current();
1247
1248         return object->checksum != old_csum;
1249 }
1250
1251 /*
1252  * Update an object's references. object->lock must be held by the caller.
1253  */
1254 static void update_refs(struct kmemleak_object *object)
1255 {
1256         if (!color_white(object)) {
1257                 /* non-orphan, ignored or new */
1258                 return;
1259         }
1260
1261         /*
1262          * Increase the object's reference count (number of pointers to the
1263          * memory block). If this count reaches the required minimum, the
1264          * object's color will become gray and it will be added to the
1265          * gray_list.
1266          */
1267         object->count++;
1268         if (color_gray(object)) {
1269                 /* put_object() called when removing from gray_list */
1270                 WARN_ON(!get_object(object));
1271                 list_add_tail(&object->gray_list, &gray_list);
1272         }
1273 }
1274
1275 /*
1276  * Memory scanning is a long process and it needs to be interruptable. This
1277  * function checks whether such interrupt condition occurred.
1278  */
1279 static int scan_should_stop(void)
1280 {
1281         if (!kmemleak_enabled)
1282                 return 1;
1283
1284         /*
1285          * This function may be called from either process or kthread context,
1286          * hence the need to check for both stop conditions.
1287          */
1288         if (current->mm)
1289                 return signal_pending(current);
1290         else
1291                 return kthread_should_stop();
1292
1293         return 0;
1294 }
1295
1296 /*
1297  * Scan a memory block (exclusive range) for valid pointers and add those
1298  * found to the gray list.
1299  */
1300 static void scan_block(void *_start, void *_end,
1301                        struct kmemleak_object *scanned)
1302 {
1303         unsigned long *ptr;
1304         unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1305         unsigned long *end = _end - (BYTES_PER_POINTER - 1);
1306         unsigned long flags;
1307
1308         read_lock_irqsave(&kmemleak_lock, flags);
1309         for (ptr = start; ptr < end; ptr++) {
1310                 struct kmemleak_object *object;
1311                 unsigned long pointer;
1312                 unsigned long excess_ref;
1313
1314                 if (scan_should_stop())
1315                         break;
1316
1317                 /* don't scan uninitialized memory */
1318                 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
1319                                                   BYTES_PER_POINTER))
1320                         continue;
1321
1322                 kasan_disable_current();
1323                 pointer = *ptr;
1324                 kasan_enable_current();
1325
1326                 if (pointer < min_addr || pointer >= max_addr)
1327                         continue;
1328
1329                 /*
1330                  * No need for get_object() here since we hold kmemleak_lock.
1331                  * object->use_count cannot be dropped to 0 while the object
1332                  * is still present in object_tree_root and object_list
1333                  * (with updates protected by kmemleak_lock).
1334                  */
1335                 object = lookup_object(pointer, 1);
1336                 if (!object)
1337                         continue;
1338                 if (object == scanned)
1339                         /* self referenced, ignore */
1340                         continue;
1341
1342                 /*
1343                  * Avoid the lockdep recursive warning on object->lock being
1344                  * previously acquired in scan_object(). These locks are
1345                  * enclosed by scan_mutex.
1346                  */
1347                 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
1348                 /* only pass surplus references (object already gray) */
1349                 if (color_gray(object)) {
1350                         excess_ref = object->excess_ref;
1351                         /* no need for update_refs() if object already gray */
1352                 } else {
1353                         excess_ref = 0;
1354                         update_refs(object);
1355                 }
1356                 spin_unlock(&object->lock);
1357
1358                 if (excess_ref) {
1359                         object = lookup_object(excess_ref, 0);
1360                         if (!object)
1361                                 continue;
1362                         if (object == scanned)
1363                                 /* circular reference, ignore */
1364                                 continue;
1365                         spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
1366                         update_refs(object);
1367                         spin_unlock(&object->lock);
1368                 }
1369         }
1370         read_unlock_irqrestore(&kmemleak_lock, flags);
1371 }
1372
1373 /*
1374  * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1375  */
1376 static void scan_large_block(void *start, void *end)
1377 {
1378         void *next;
1379
1380         while (start < end) {
1381                 next = min(start + MAX_SCAN_SIZE, end);
1382                 scan_block(start, next, NULL);
1383                 start = next;
1384                 cond_resched();
1385         }
1386 }
1387
1388 /*
1389  * Scan a memory block corresponding to a kmemleak_object. A condition is
1390  * that object->use_count >= 1.
1391  */
1392 static void scan_object(struct kmemleak_object *object)
1393 {
1394         struct kmemleak_scan_area *area;
1395         unsigned long flags;
1396
1397         /*
1398          * Once the object->lock is acquired, the corresponding memory block
1399          * cannot be freed (the same lock is acquired in delete_object).
1400          */
1401         spin_lock_irqsave(&object->lock, flags);
1402         if (object->flags & OBJECT_NO_SCAN)
1403                 goto out;
1404         if (!(object->flags & OBJECT_ALLOCATED))
1405                 /* already freed object */
1406                 goto out;
1407         if (hlist_empty(&object->area_list)) {
1408                 void *start = (void *)object->pointer;
1409                 void *end = (void *)(object->pointer + object->size);
1410                 void *next;
1411
1412                 do {
1413                         next = min(start + MAX_SCAN_SIZE, end);
1414                         scan_block(start, next, object);
1415
1416                         start = next;
1417                         if (start >= end)
1418                                 break;
1419
1420                         spin_unlock_irqrestore(&object->lock, flags);
1421                         cond_resched();
1422                         spin_lock_irqsave(&object->lock, flags);
1423                 } while (object->flags & OBJECT_ALLOCATED);
1424         } else
1425                 hlist_for_each_entry(area, &object->area_list, node)
1426                         scan_block((void *)area->start,
1427                                    (void *)(area->start + area->size),
1428                                    object);
1429 out:
1430         spin_unlock_irqrestore(&object->lock, flags);
1431 }
1432
1433 /*
1434  * Scan the objects already referenced (gray objects). More objects will be
1435  * referenced and, if there are no memory leaks, all the objects are scanned.
1436  */
1437 static void scan_gray_list(void)
1438 {
1439         struct kmemleak_object *object, *tmp;
1440
1441         /*
1442          * The list traversal is safe for both tail additions and removals
1443          * from inside the loop. The kmemleak objects cannot be freed from
1444          * outside the loop because their use_count was incremented.
1445          */
1446         object = list_entry(gray_list.next, typeof(*object), gray_list);
1447         while (&object->gray_list != &gray_list) {
1448                 cond_resched();
1449
1450                 /* may add new objects to the list */
1451                 if (!scan_should_stop())
1452                         scan_object(object);
1453
1454                 tmp = list_entry(object->gray_list.next, typeof(*object),
1455                                  gray_list);
1456
1457                 /* remove the object from the list and release it */
1458                 list_del(&object->gray_list);
1459                 put_object(object);
1460
1461                 object = tmp;
1462         }
1463         WARN_ON(!list_empty(&gray_list));
1464 }
1465
1466 /*
1467  * Scan data sections and all the referenced memory blocks allocated via the
1468  * kernel's standard allocators. This function must be called with the
1469  * scan_mutex held.
1470  */
1471 static void kmemleak_scan(void)
1472 {
1473         unsigned long flags;
1474         struct kmemleak_object *object;
1475         int i;
1476         int new_leaks = 0;
1477
1478         jiffies_last_scan = jiffies;
1479
1480         /* prepare the kmemleak_object's */
1481         rcu_read_lock();
1482         list_for_each_entry_rcu(object, &object_list, object_list) {
1483                 spin_lock_irqsave(&object->lock, flags);
1484 #ifdef DEBUG
1485                 /*
1486                  * With a few exceptions there should be a maximum of
1487                  * 1 reference to any object at this point.
1488                  */
1489                 if (atomic_read(&object->use_count) > 1) {
1490                         pr_debug("object->use_count = %d\n",
1491                                  atomic_read(&object->use_count));
1492                         dump_object_info(object);
1493                 }
1494 #endif
1495                 /* reset the reference count (whiten the object) */
1496                 object->count = 0;
1497                 if (color_gray(object) && get_object(object))
1498                         list_add_tail(&object->gray_list, &gray_list);
1499
1500                 spin_unlock_irqrestore(&object->lock, flags);
1501         }
1502         rcu_read_unlock();
1503
1504         /* data/bss scanning */
1505         scan_large_block(_sdata, _edata);
1506         scan_large_block(__bss_start, __bss_stop);
1507         scan_large_block(__start_ro_after_init, __end_ro_after_init);
1508
1509 #ifdef CONFIG_SMP
1510         /* per-cpu sections scanning */
1511         for_each_possible_cpu(i)
1512                 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1513                                  __per_cpu_end + per_cpu_offset(i));
1514 #endif
1515
1516         /*
1517          * Struct page scanning for each node.
1518          */
1519         get_online_mems();
1520         for_each_online_node(i) {
1521                 unsigned long start_pfn = node_start_pfn(i);
1522                 unsigned long end_pfn = node_end_pfn(i);
1523                 unsigned long pfn;
1524
1525                 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1526                         struct page *page;
1527
1528                         if (!pfn_valid(pfn))
1529                                 continue;
1530                         page = pfn_to_page(pfn);
1531                         /* only scan if page is in use */
1532                         if (page_count(page) == 0)
1533                                 continue;
1534                         scan_block(page, page + 1, NULL);
1535                 }
1536         }
1537         put_online_mems();
1538
1539         /*
1540          * Scanning the task stacks (may introduce false negatives).
1541          */
1542         if (kmemleak_stack_scan) {
1543                 struct task_struct *p, *g;
1544
1545                 read_lock(&tasklist_lock);
1546                 do_each_thread(g, p) {
1547                         void *stack = try_get_task_stack(p);
1548                         if (stack) {
1549                                 scan_block(stack, stack + THREAD_SIZE, NULL);
1550                                 put_task_stack(p);
1551                         }
1552                 } while_each_thread(g, p);
1553                 read_unlock(&tasklist_lock);
1554         }
1555
1556         /*
1557          * Scan the objects already referenced from the sections scanned
1558          * above.
1559          */
1560         scan_gray_list();
1561
1562         /*
1563          * Check for new or unreferenced objects modified since the previous
1564          * scan and color them gray until the next scan.
1565          */
1566         rcu_read_lock();
1567         list_for_each_entry_rcu(object, &object_list, object_list) {
1568                 spin_lock_irqsave(&object->lock, flags);
1569                 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1570                     && update_checksum(object) && get_object(object)) {
1571                         /* color it gray temporarily */
1572                         object->count = object->min_count;
1573                         list_add_tail(&object->gray_list, &gray_list);
1574                 }
1575                 spin_unlock_irqrestore(&object->lock, flags);
1576         }
1577         rcu_read_unlock();
1578
1579         /*
1580          * Re-scan the gray list for modified unreferenced objects.
1581          */
1582         scan_gray_list();
1583
1584         /*
1585          * If scanning was stopped do not report any new unreferenced objects.
1586          */
1587         if (scan_should_stop())
1588                 return;
1589
1590         /*
1591          * Scanning result reporting.
1592          */
1593         rcu_read_lock();
1594         list_for_each_entry_rcu(object, &object_list, object_list) {
1595                 spin_lock_irqsave(&object->lock, flags);
1596                 if (unreferenced_object(object) &&
1597                     !(object->flags & OBJECT_REPORTED)) {
1598                         object->flags |= OBJECT_REPORTED;
1599                         new_leaks++;
1600                 }
1601                 spin_unlock_irqrestore(&object->lock, flags);
1602         }
1603         rcu_read_unlock();
1604
1605         if (new_leaks) {
1606                 kmemleak_found_leaks = true;
1607
1608                 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1609                         new_leaks);
1610         }
1611
1612 }
1613
1614 /*
1615  * Thread function performing automatic memory scanning. Unreferenced objects
1616  * at the end of a memory scan are reported but only the first time.
1617  */
1618 static int kmemleak_scan_thread(void *arg)
1619 {
1620         static int first_run = 1;
1621
1622         pr_info("Automatic memory scanning thread started\n");
1623         set_user_nice(current, 10);
1624
1625         /*
1626          * Wait before the first scan to allow the system to fully initialize.
1627          */
1628         if (first_run) {
1629                 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
1630                 first_run = 0;
1631                 while (timeout && !kthread_should_stop())
1632                         timeout = schedule_timeout_interruptible(timeout);
1633         }
1634
1635         while (!kthread_should_stop()) {
1636                 signed long timeout = jiffies_scan_wait;
1637
1638                 mutex_lock(&scan_mutex);
1639                 kmemleak_scan();
1640                 mutex_unlock(&scan_mutex);
1641
1642                 /* wait before the next scan */
1643                 while (timeout && !kthread_should_stop())
1644                         timeout = schedule_timeout_interruptible(timeout);
1645         }
1646
1647         pr_info("Automatic memory scanning thread ended\n");
1648
1649         return 0;
1650 }
1651
1652 /*
1653  * Start the automatic memory scanning thread. This function must be called
1654  * with the scan_mutex held.
1655  */
1656 static void start_scan_thread(void)
1657 {
1658         if (scan_thread)
1659                 return;
1660         scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1661         if (IS_ERR(scan_thread)) {
1662                 pr_warn("Failed to create the scan thread\n");
1663                 scan_thread = NULL;
1664         }
1665 }
1666
1667 /*
1668  * Stop the automatic memory scanning thread. This function must be called
1669  * with the scan_mutex held.
1670  */
1671 static void stop_scan_thread(void)
1672 {
1673         if (scan_thread) {
1674                 kthread_stop(scan_thread);
1675                 scan_thread = NULL;
1676         }
1677 }
1678
1679 /*
1680  * Iterate over the object_list and return the first valid object at or after
1681  * the required position with its use_count incremented. The function triggers
1682  * a memory scanning when the pos argument points to the first position.
1683  */
1684 static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1685 {
1686         struct kmemleak_object *object;
1687         loff_t n = *pos;
1688         int err;
1689
1690         err = mutex_lock_interruptible(&scan_mutex);
1691         if (err < 0)
1692                 return ERR_PTR(err);
1693
1694         rcu_read_lock();
1695         list_for_each_entry_rcu(object, &object_list, object_list) {
1696                 if (n-- > 0)
1697                         continue;
1698                 if (get_object(object))
1699                         goto out;
1700         }
1701         object = NULL;
1702 out:
1703         return object;
1704 }
1705
1706 /*
1707  * Return the next object in the object_list. The function decrements the
1708  * use_count of the previous object and increases that of the next one.
1709  */
1710 static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1711 {
1712         struct kmemleak_object *prev_obj = v;
1713         struct kmemleak_object *next_obj = NULL;
1714         struct kmemleak_object *obj = prev_obj;
1715
1716         ++(*pos);
1717
1718         list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
1719                 if (get_object(obj)) {
1720                         next_obj = obj;
1721                         break;
1722                 }
1723         }
1724
1725         put_object(prev_obj);
1726         return next_obj;
1727 }
1728
1729 /*
1730  * Decrement the use_count of the last object required, if any.
1731  */
1732 static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1733 {
1734         if (!IS_ERR(v)) {
1735                 /*
1736                  * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1737                  * waiting was interrupted, so only release it if !IS_ERR.
1738                  */
1739                 rcu_read_unlock();
1740                 mutex_unlock(&scan_mutex);
1741                 if (v)
1742                         put_object(v);
1743         }
1744 }
1745
1746 /*
1747  * Print the information for an unreferenced object to the seq file.
1748  */
1749 static int kmemleak_seq_show(struct seq_file *seq, void *v)
1750 {
1751         struct kmemleak_object *object = v;
1752         unsigned long flags;
1753
1754         spin_lock_irqsave(&object->lock, flags);
1755         if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
1756                 print_unreferenced(seq, object);
1757         spin_unlock_irqrestore(&object->lock, flags);
1758         return 0;
1759 }
1760
1761 static const struct seq_operations kmemleak_seq_ops = {
1762         .start = kmemleak_seq_start,
1763         .next  = kmemleak_seq_next,
1764         .stop  = kmemleak_seq_stop,
1765         .show  = kmemleak_seq_show,
1766 };
1767
1768 static int kmemleak_open(struct inode *inode, struct file *file)
1769 {
1770         return seq_open(file, &kmemleak_seq_ops);
1771 }
1772
1773 static int dump_str_object_info(const char *str)
1774 {
1775         unsigned long flags;
1776         struct kmemleak_object *object;
1777         unsigned long addr;
1778
1779         if (kstrtoul(str, 0, &addr))
1780                 return -EINVAL;
1781         object = find_and_get_object(addr, 0);
1782         if (!object) {
1783                 pr_info("Unknown object at 0x%08lx\n", addr);
1784                 return -EINVAL;
1785         }
1786
1787         spin_lock_irqsave(&object->lock, flags);
1788         dump_object_info(object);
1789         spin_unlock_irqrestore(&object->lock, flags);
1790
1791         put_object(object);
1792         return 0;
1793 }
1794
1795 /*
1796  * We use grey instead of black to ensure we can do future scans on the same
1797  * objects. If we did not do future scans these black objects could
1798  * potentially contain references to newly allocated objects in the future and
1799  * we'd end up with false positives.
1800  */
1801 static void kmemleak_clear(void)
1802 {
1803         struct kmemleak_object *object;
1804         unsigned long flags;
1805
1806         rcu_read_lock();
1807         list_for_each_entry_rcu(object, &object_list, object_list) {
1808                 spin_lock_irqsave(&object->lock, flags);
1809                 if ((object->flags & OBJECT_REPORTED) &&
1810                     unreferenced_object(object))
1811                         __paint_it(object, KMEMLEAK_GREY);
1812                 spin_unlock_irqrestore(&object->lock, flags);
1813         }
1814         rcu_read_unlock();
1815
1816         kmemleak_found_leaks = false;
1817 }
1818
1819 static void __kmemleak_do_cleanup(void);
1820
1821 /*
1822  * File write operation to configure kmemleak at run-time. The following
1823  * commands can be written to the /sys/kernel/debug/kmemleak file:
1824  *   off        - disable kmemleak (irreversible)
1825  *   stack=on   - enable the task stacks scanning
1826  *   stack=off  - disable the tasks stacks scanning
1827  *   scan=on    - start the automatic memory scanning thread
1828  *   scan=off   - stop the automatic memory scanning thread
1829  *   scan=...   - set the automatic memory scanning period in seconds (0 to
1830  *                disable it)
1831  *   scan       - trigger a memory scan
1832  *   clear      - mark all current reported unreferenced kmemleak objects as
1833  *                grey to ignore printing them, or free all kmemleak objects
1834  *                if kmemleak has been disabled.
1835  *   dump=...   - dump information about the object found at the given address
1836  */
1837 static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1838                               size_t size, loff_t *ppos)
1839 {
1840         char buf[64];
1841         int buf_size;
1842         int ret;
1843
1844         buf_size = min(size, (sizeof(buf) - 1));
1845         if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1846                 return -EFAULT;
1847         buf[buf_size] = 0;
1848
1849         ret = mutex_lock_interruptible(&scan_mutex);
1850         if (ret < 0)
1851                 return ret;
1852
1853         if (strncmp(buf, "clear", 5) == 0) {
1854                 if (kmemleak_enabled)
1855                         kmemleak_clear();
1856                 else
1857                         __kmemleak_do_cleanup();
1858                 goto out;
1859         }
1860
1861         if (!kmemleak_enabled) {
1862                 ret = -EBUSY;
1863                 goto out;
1864         }
1865
1866         if (strncmp(buf, "off", 3) == 0)
1867                 kmemleak_disable();
1868         else if (strncmp(buf, "stack=on", 8) == 0)
1869                 kmemleak_stack_scan = 1;
1870         else if (strncmp(buf, "stack=off", 9) == 0)
1871                 kmemleak_stack_scan = 0;
1872         else if (strncmp(buf, "scan=on", 7) == 0)
1873                 start_scan_thread();
1874         else if (strncmp(buf, "scan=off", 8) == 0)
1875                 stop_scan_thread();
1876         else if (strncmp(buf, "scan=", 5) == 0) {
1877                 unsigned long secs;
1878
1879                 ret = kstrtoul(buf + 5, 0, &secs);
1880                 if (ret < 0)
1881                         goto out;
1882                 stop_scan_thread();
1883                 if (secs) {
1884                         jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1885                         start_scan_thread();
1886                 }
1887         } else if (strncmp(buf, "scan", 4) == 0)
1888                 kmemleak_scan();
1889         else if (strncmp(buf, "dump=", 5) == 0)
1890                 ret = dump_str_object_info(buf + 5);
1891         else
1892                 ret = -EINVAL;
1893
1894 out:
1895         mutex_unlock(&scan_mutex);
1896         if (ret < 0)
1897                 return ret;
1898
1899         /* ignore the rest of the buffer, only one command at a time */
1900         *ppos += size;
1901         return size;
1902 }
1903
1904 static const struct file_operations kmemleak_fops = {
1905         .owner          = THIS_MODULE,
1906         .open           = kmemleak_open,
1907         .read           = seq_read,
1908         .write          = kmemleak_write,
1909         .llseek         = seq_lseek,
1910         .release        = seq_release,
1911 };
1912
1913 static void __kmemleak_do_cleanup(void)
1914 {
1915         struct kmemleak_object *object;
1916
1917         rcu_read_lock();
1918         list_for_each_entry_rcu(object, &object_list, object_list)
1919                 delete_object_full(object->pointer);
1920         rcu_read_unlock();
1921 }
1922
1923 /*
1924  * Stop the memory scanning thread and free the kmemleak internal objects if
1925  * no previous scan thread (otherwise, kmemleak may still have some useful
1926  * information on memory leaks).
1927  */
1928 static void kmemleak_do_cleanup(struct work_struct *work)
1929 {
1930         stop_scan_thread();
1931
1932         /*
1933          * Once the scan thread has stopped, it is safe to no longer track
1934          * object freeing. Ordering of the scan thread stopping and the memory
1935          * accesses below is guaranteed by the kthread_stop() function.
1936          */
1937         kmemleak_free_enabled = 0;
1938
1939         if (!kmemleak_found_leaks)
1940                 __kmemleak_do_cleanup();
1941         else
1942                 pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n");
1943 }
1944
1945 static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
1946
1947 /*
1948  * Disable kmemleak. No memory allocation/freeing will be traced once this
1949  * function is called. Disabling kmemleak is an irreversible operation.
1950  */
1951 static void kmemleak_disable(void)
1952 {
1953         /* atomically check whether it was already invoked */
1954         if (cmpxchg(&kmemleak_error, 0, 1))
1955                 return;
1956
1957         /* stop any memory operation tracing */
1958         kmemleak_enabled = 0;
1959
1960         /* check whether it is too early for a kernel thread */
1961         if (kmemleak_initialized)
1962                 schedule_work(&cleanup_work);
1963         else
1964                 kmemleak_free_enabled = 0;
1965
1966         pr_info("Kernel memory leak detector disabled\n");
1967 }
1968
1969 /*
1970  * Allow boot-time kmemleak disabling (enabled by default).
1971  */
1972 static int kmemleak_boot_config(char *str)
1973 {
1974         if (!str)
1975                 return -EINVAL;
1976         if (strcmp(str, "off") == 0)
1977                 kmemleak_disable();
1978         else if (strcmp(str, "on") == 0)
1979                 kmemleak_skip_disable = 1;
1980         else
1981                 return -EINVAL;
1982         return 0;
1983 }
1984 early_param("kmemleak", kmemleak_boot_config);
1985
1986 static void __init print_log_trace(struct early_log *log)
1987 {
1988         struct stack_trace trace;
1989
1990         trace.nr_entries = log->trace_len;
1991         trace.entries = log->trace;
1992
1993         pr_notice("Early log backtrace:\n");
1994         print_stack_trace(&trace, 2);
1995 }
1996
1997 /*
1998  * Kmemleak initialization.
1999  */
2000 void __init kmemleak_init(void)
2001 {
2002         int i;
2003         unsigned long flags;
2004
2005 #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
2006         if (!kmemleak_skip_disable) {
2007                 kmemleak_early_log = 0;
2008                 kmemleak_disable();
2009                 return;
2010         }
2011 #endif
2012
2013         jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
2014         jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
2015
2016         object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
2017         scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
2018
2019         if (crt_early_log > ARRAY_SIZE(early_log))
2020                 pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
2021                         crt_early_log);
2022
2023         /* the kernel is still in UP mode, so disabling the IRQs is enough */
2024         local_irq_save(flags);
2025         kmemleak_early_log = 0;
2026         if (kmemleak_error) {
2027                 local_irq_restore(flags);
2028                 return;
2029         } else {
2030                 kmemleak_enabled = 1;
2031                 kmemleak_free_enabled = 1;
2032         }
2033         local_irq_restore(flags);
2034
2035         /*
2036          * This is the point where tracking allocations is safe. Automatic
2037          * scanning is started during the late initcall. Add the early logged
2038          * callbacks to the kmemleak infrastructure.
2039          */
2040         for (i = 0; i < crt_early_log; i++) {
2041                 struct early_log *log = &early_log[i];
2042
2043                 switch (log->op_type) {
2044                 case KMEMLEAK_ALLOC:
2045                         early_alloc(log);
2046                         break;
2047                 case KMEMLEAK_ALLOC_PERCPU:
2048                         early_alloc_percpu(log);
2049                         break;
2050                 case KMEMLEAK_FREE:
2051                         kmemleak_free(log->ptr);
2052                         break;
2053                 case KMEMLEAK_FREE_PART:
2054                         kmemleak_free_part(log->ptr, log->size);
2055                         break;
2056                 case KMEMLEAK_FREE_PERCPU:
2057                         kmemleak_free_percpu(log->ptr);
2058                         break;
2059                 case KMEMLEAK_NOT_LEAK:
2060                         kmemleak_not_leak(log->ptr);
2061                         break;
2062                 case KMEMLEAK_IGNORE:
2063                         kmemleak_ignore(log->ptr);
2064                         break;
2065                 case KMEMLEAK_SCAN_AREA:
2066                         kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
2067                         break;
2068                 case KMEMLEAK_NO_SCAN:
2069                         kmemleak_no_scan(log->ptr);
2070                         break;
2071                 case KMEMLEAK_SET_EXCESS_REF:
2072                         object_set_excess_ref((unsigned long)log->ptr,
2073                                               log->excess_ref);
2074                         break;
2075                 default:
2076                         kmemleak_warn("Unknown early log operation: %d\n",
2077                                       log->op_type);
2078                 }
2079
2080                 if (kmemleak_warning) {
2081                         print_log_trace(log);
2082                         kmemleak_warning = 0;
2083                 }
2084         }
2085 }
2086
2087 /*
2088  * Late initialization function.
2089  */
2090 static int __init kmemleak_late_init(void)
2091 {
2092         struct dentry *dentry;
2093
2094         kmemleak_initialized = 1;
2095
2096         if (kmemleak_error) {
2097                 /*
2098                  * Some error occurred and kmemleak was disabled. There is a
2099                  * small chance that kmemleak_disable() was called immediately
2100                  * after setting kmemleak_initialized and we may end up with
2101                  * two clean-up threads but serialized by scan_mutex.
2102                  */
2103                 schedule_work(&cleanup_work);
2104                 return -ENOMEM;
2105         }
2106
2107         dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
2108                                      &kmemleak_fops);
2109         if (!dentry)
2110                 pr_warn("Failed to create the debugfs kmemleak file\n");
2111         mutex_lock(&scan_mutex);
2112         start_scan_thread();
2113         mutex_unlock(&scan_mutex);
2114
2115         pr_info("Kernel memory leak detector initialized\n");
2116
2117         return 0;
2118 }
2119 late_initcall(kmemleak_late_init);