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Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001/*
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/kmemleak.txt.
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 priority search tree used to look-up
33 * metadata based on a pointer to the corresponding memory block. The
34 * kmemleak_object structures are added to the object_list and
35 * object_tree_root in the create_object() function called from the
36 * kmemleak_alloc() callback and removed in delete_object() called from the
37 * kmemleak_free() callback
38 * - kmemleak_object.lock (spinlock): protects a kmemleak_object. Accesses to
39 * the metadata (e.g. count) are protected by this lock. Note that some
40 * members of this structure may be protected by other means (atomic or
41 * kmemleak_lock). This lock is also held when scanning the corresponding
42 * memory block to avoid the kernel freeing it via the kmemleak_free()
43 * callback. This is less heavyweight than holding a global lock like
44 * kmemleak_lock during scanning
45 * - scan_mutex (mutex): ensures that only one thread may scan the memory for
46 * unreferenced objects at a time. The gray_list contains the objects which
47 * are already referenced or marked as false positives and need to be
48 * scanned. This list is only modified during a scanning episode when the
49 * scan_mutex is held. At the end of a scan, the gray_list is always empty.
50 * Note that the kmemleak_object.use_count is incremented when an object is
Catalin Marinas4698c1f2009-06-26 17:38:27 +010051 * 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
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010055 *
56 * The kmemleak_object structures have a use_count incremented or decremented
57 * using the get_object()/put_object() functions. When the use_count becomes
58 * 0, this count can no longer be incremented and put_object() schedules the
59 * kmemleak_object freeing via an RCU callback. All calls to the get_object()
60 * function must be protected by rcu_read_lock() to avoid accessing a freed
61 * structure.
62 */
63
Joe Perchesae281062009-06-23 14:40:26 +010064#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
65
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010066#include <linux/init.h>
67#include <linux/kernel.h>
68#include <linux/list.h>
69#include <linux/sched.h>
70#include <linux/jiffies.h>
71#include <linux/delay.h>
72#include <linux/module.h>
73#include <linux/kthread.h>
74#include <linux/prio_tree.h>
75#include <linux/gfp.h>
76#include <linux/fs.h>
77#include <linux/debugfs.h>
78#include <linux/seq_file.h>
79#include <linux/cpumask.h>
80#include <linux/spinlock.h>
81#include <linux/mutex.h>
82#include <linux/rcupdate.h>
83#include <linux/stacktrace.h>
84#include <linux/cache.h>
85#include <linux/percpu.h>
86#include <linux/hardirq.h>
87#include <linux/mmzone.h>
88#include <linux/slab.h>
89#include <linux/thread_info.h>
90#include <linux/err.h>
91#include <linux/uaccess.h>
92#include <linux/string.h>
93#include <linux/nodemask.h>
94#include <linux/mm.h>
Catalin Marinas179a8102009-09-07 10:14:42 +010095#include <linux/workqueue.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010096
97#include <asm/sections.h>
98#include <asm/processor.h>
99#include <asm/atomic.h>
100
Pekka Enberg8e019362009-08-27 14:50:00 +0100101#include <linux/kmemcheck.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100102#include <linux/kmemleak.h>
103
104/*
105 * Kmemleak configuration and common defines.
106 */
107#define MAX_TRACE 16 /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100108#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100109#define SECS_FIRST_SCAN 60 /* delay before the first scan */
110#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
Catalin Marinas25873622009-07-07 10:32:58 +0100111#define GRAY_LIST_PASSES 25 /* maximum number of gray list scans */
Catalin Marinasaf986032009-08-27 14:29:12 +0100112#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100113
114#define BYTES_PER_POINTER sizeof(void *)
115
Catalin Marinas216c04b2009-06-17 18:29:02 +0100116/* GFP bitmask for kmemleak internal allocations */
117#define GFP_KMEMLEAK_MASK (GFP_KERNEL | GFP_ATOMIC)
118
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100119/* scanning area inside a memory block */
120struct kmemleak_scan_area {
121 struct hlist_node node;
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000122 unsigned long start;
123 size_t size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100124};
125
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700126#define KMEMLEAK_GREY 0
127#define KMEMLEAK_BLACK -1
128
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100129/*
130 * Structure holding the metadata for each allocated memory block.
131 * Modifications to such objects should be made while holding the
132 * object->lock. Insertions or deletions from object_list, gray_list or
133 * tree_node are already protected by the corresponding locks or mutex (see
134 * the notes on locking above). These objects are reference-counted
135 * (use_count) and freed using the RCU mechanism.
136 */
137struct kmemleak_object {
138 spinlock_t lock;
139 unsigned long flags; /* object status flags */
140 struct list_head object_list;
141 struct list_head gray_list;
142 struct prio_tree_node tree_node;
143 struct rcu_head rcu; /* object_list lockless traversal */
144 /* object usage count; object freed when use_count == 0 */
145 atomic_t use_count;
146 unsigned long pointer;
147 size_t size;
148 /* minimum number of a pointers found before it is considered leak */
149 int min_count;
150 /* the total number of pointers found pointing to this object */
151 int count;
152 /* memory ranges to be scanned inside an object (empty for all) */
153 struct hlist_head area_list;
154 unsigned long trace[MAX_TRACE];
155 unsigned int trace_len;
156 unsigned long jiffies; /* creation timestamp */
157 pid_t pid; /* pid of the current task */
158 char comm[TASK_COMM_LEN]; /* executable name */
159};
160
161/* flag representing the memory block allocation status */
162#define OBJECT_ALLOCATED (1 << 0)
163/* flag set after the first reporting of an unreference object */
164#define OBJECT_REPORTED (1 << 1)
165/* flag set to not scan the object */
166#define OBJECT_NO_SCAN (1 << 2)
Catalin Marinas25873622009-07-07 10:32:58 +0100167/* flag set on newly allocated objects */
168#define OBJECT_NEW (1 << 3)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100169
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100170/* number of bytes to print per line; must be 16 or 32 */
171#define HEX_ROW_SIZE 16
172/* number of bytes to print at a time (1, 2, 4, 8) */
173#define HEX_GROUP_SIZE 1
174/* include ASCII after the hex output */
175#define HEX_ASCII 1
176/* max number of lines to be printed */
177#define HEX_MAX_LINES 2
178
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100179/* the list of all allocated objects */
180static LIST_HEAD(object_list);
181/* the list of gray-colored objects (see color_gray comment below) */
182static LIST_HEAD(gray_list);
183/* prio search tree for object boundaries */
184static struct prio_tree_root object_tree_root;
185/* rw_lock protecting the access to object_list and prio_tree_root */
186static DEFINE_RWLOCK(kmemleak_lock);
187
188/* allocation caches for kmemleak internal data */
189static struct kmem_cache *object_cache;
190static struct kmem_cache *scan_area_cache;
191
192/* set if tracing memory operations is enabled */
193static atomic_t kmemleak_enabled = ATOMIC_INIT(0);
194/* set in the late_initcall if there were no errors */
195static atomic_t kmemleak_initialized = ATOMIC_INIT(0);
196/* enables or disables early logging of the memory operations */
197static atomic_t kmemleak_early_log = ATOMIC_INIT(1);
198/* set if a fata kmemleak error has occurred */
199static atomic_t kmemleak_error = ATOMIC_INIT(0);
200
201/* minimum and maximum address that may be valid pointers */
202static unsigned long min_addr = ULONG_MAX;
203static unsigned long max_addr;
204
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100205static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100206/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100207static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100208static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100209/* delay between automatic memory scannings */
210static signed long jiffies_scan_wait;
211/* enables or disables the task stacks scanning */
Catalin Marinase0a2a162009-06-26 17:38:25 +0100212static int kmemleak_stack_scan = 1;
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100213/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100214static DEFINE_MUTEX(scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100215
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100216/*
Catalin Marinas20301172009-06-17 18:29:04 +0100217 * Early object allocation/freeing logging. Kmemleak is initialized after the
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100218 * kernel allocator. However, both the kernel allocator and kmemleak may
Catalin Marinas20301172009-06-17 18:29:04 +0100219 * allocate memory blocks which need to be tracked. Kmemleak defines an
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100220 * arbitrary buffer to hold the allocation/freeing information before it is
221 * fully initialized.
222 */
223
224/* kmemleak operation type for early logging */
225enum {
226 KMEMLEAK_ALLOC,
227 KMEMLEAK_FREE,
Catalin Marinas53238a62009-07-07 10:33:00 +0100228 KMEMLEAK_FREE_PART,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100229 KMEMLEAK_NOT_LEAK,
230 KMEMLEAK_IGNORE,
231 KMEMLEAK_SCAN_AREA,
232 KMEMLEAK_NO_SCAN
233};
234
235/*
236 * Structure holding the information passed to kmemleak callbacks during the
237 * early logging.
238 */
239struct early_log {
240 int op_type; /* kmemleak operation type */
241 const void *ptr; /* allocated/freed memory block */
242 size_t size; /* memory block size */
243 int min_count; /* minimum reference count */
Catalin Marinasfd678962009-08-27 14:29:17 +0100244 unsigned long trace[MAX_TRACE]; /* stack trace */
245 unsigned int trace_len; /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100246};
247
248/* early logging buffer and current position */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100249static struct early_log
250 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
251static int crt_early_log __initdata;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100252
253static void kmemleak_disable(void);
254
255/*
256 * Print a warning and dump the stack trace.
257 */
258#define kmemleak_warn(x...) do { \
259 pr_warning(x); \
260 dump_stack(); \
261} while (0)
262
263/*
264 * Macro invoked when a serious kmemleak condition occured and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100265 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100266 * tracing no longer available.
267 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100268#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100269 kmemleak_warn(x); \
270 kmemleak_disable(); \
271} while (0)
272
273/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100274 * Printing of the objects hex dump to the seq file. The number of lines to be
275 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
276 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
277 * with the object->lock held.
278 */
279static void hex_dump_object(struct seq_file *seq,
280 struct kmemleak_object *object)
281{
282 const u8 *ptr = (const u8 *)object->pointer;
283 int i, len, remaining;
284 unsigned char linebuf[HEX_ROW_SIZE * 5];
285
286 /* limit the number of lines to HEX_MAX_LINES */
287 remaining = len =
288 min(object->size, (size_t)(HEX_MAX_LINES * HEX_ROW_SIZE));
289
290 seq_printf(seq, " hex dump (first %d bytes):\n", len);
291 for (i = 0; i < len; i += HEX_ROW_SIZE) {
292 int linelen = min(remaining, HEX_ROW_SIZE);
293
294 remaining -= HEX_ROW_SIZE;
295 hex_dump_to_buffer(ptr + i, linelen, HEX_ROW_SIZE,
296 HEX_GROUP_SIZE, linebuf, sizeof(linebuf),
297 HEX_ASCII);
298 seq_printf(seq, " %s\n", linebuf);
299 }
300}
301
302/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100303 * Object colors, encoded with count and min_count:
304 * - white - orphan object, not enough references to it (count < min_count)
305 * - gray - not orphan, not marked as false positive (min_count == 0) or
306 * sufficient references to it (count >= min_count)
307 * - black - ignore, it doesn't contain references (e.g. text section)
308 * (min_count == -1). No function defined for this color.
309 * Newly created objects don't have any color assigned (object->count == -1)
310 * before the next memory scan when they become white.
311 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100312static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100313{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700314 return object->count != KMEMLEAK_BLACK &&
315 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100316}
317
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100318static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100319{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700320 return object->min_count != KMEMLEAK_BLACK &&
321 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100322}
323
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100324static bool color_black(const struct kmemleak_object *object)
Catalin Marinas25873622009-07-07 10:32:58 +0100325{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700326 return object->min_count == KMEMLEAK_BLACK;
Catalin Marinas25873622009-07-07 10:32:58 +0100327}
328
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100329/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100330 * Objects are considered unreferenced only if their color is white, they have
331 * not be deleted and have a minimum age to avoid false positives caused by
332 * pointers temporarily stored in CPU registers.
333 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100334static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100335{
336 return (object->flags & OBJECT_ALLOCATED) && color_white(object) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100337 time_before_eq(object->jiffies + jiffies_min_age,
338 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100339}
340
341/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100342 * Printing of the unreferenced objects information to the seq file. The
343 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100344 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100345static void print_unreferenced(struct seq_file *seq,
346 struct kmemleak_object *object)
347{
348 int i;
349
Catalin Marinasbab4a342009-06-26 17:38:26 +0100350 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
351 object->pointer, object->size);
352 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n",
353 object->comm, object->pid, object->jiffies);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100354 hex_dump_object(seq, object);
Catalin Marinasbab4a342009-06-26 17:38:26 +0100355 seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100356
357 for (i = 0; i < object->trace_len; i++) {
358 void *ptr = (void *)object->trace[i];
Catalin Marinasbab4a342009-06-26 17:38:26 +0100359 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100360 }
361}
362
363/*
364 * Print the kmemleak_object information. This function is used mainly for
365 * debugging special cases when kmemleak operations. It must be called with
366 * the object->lock held.
367 */
368static void dump_object_info(struct kmemleak_object *object)
369{
370 struct stack_trace trace;
371
372 trace.nr_entries = object->trace_len;
373 trace.entries = object->trace;
374
Joe Perchesae281062009-06-23 14:40:26 +0100375 pr_notice("Object 0x%08lx (size %zu):\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100376 object->tree_node.start, object->size);
377 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
378 object->comm, object->pid, object->jiffies);
379 pr_notice(" min_count = %d\n", object->min_count);
380 pr_notice(" count = %d\n", object->count);
Catalin Marinas189d84e2009-08-27 14:29:15 +0100381 pr_notice(" flags = 0x%lx\n", object->flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100382 pr_notice(" backtrace:\n");
383 print_stack_trace(&trace, 4);
384}
385
386/*
387 * Look-up a memory block metadata (kmemleak_object) in the priority search
388 * tree based on a pointer value. If alias is 0, only values pointing to the
389 * beginning of the memory block are allowed. The kmemleak_lock must be held
390 * when calling this function.
391 */
392static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
393{
394 struct prio_tree_node *node;
395 struct prio_tree_iter iter;
396 struct kmemleak_object *object;
397
398 prio_tree_iter_init(&iter, &object_tree_root, ptr, ptr);
399 node = prio_tree_next(&iter);
400 if (node) {
401 object = prio_tree_entry(node, struct kmemleak_object,
402 tree_node);
403 if (!alias && object->pointer != ptr) {
Joe Perchesae281062009-06-23 14:40:26 +0100404 kmemleak_warn("Found object by alias");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100405 object = NULL;
406 }
407 } else
408 object = NULL;
409
410 return object;
411}
412
413/*
414 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
415 * that once an object's use_count reached 0, the RCU freeing was already
416 * registered and the object should no longer be used. This function must be
417 * called under the protection of rcu_read_lock().
418 */
419static int get_object(struct kmemleak_object *object)
420{
421 return atomic_inc_not_zero(&object->use_count);
422}
423
424/*
425 * RCU callback to free a kmemleak_object.
426 */
427static void free_object_rcu(struct rcu_head *rcu)
428{
429 struct hlist_node *elem, *tmp;
430 struct kmemleak_scan_area *area;
431 struct kmemleak_object *object =
432 container_of(rcu, struct kmemleak_object, rcu);
433
434 /*
435 * Once use_count is 0 (guaranteed by put_object), there is no other
436 * code accessing this object, hence no need for locking.
437 */
438 hlist_for_each_entry_safe(area, elem, tmp, &object->area_list, node) {
439 hlist_del(elem);
440 kmem_cache_free(scan_area_cache, area);
441 }
442 kmem_cache_free(object_cache, object);
443}
444
445/*
446 * Decrement the object use_count. Once the count is 0, free the object using
447 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
448 * delete_object() path, the delayed RCU freeing ensures that there is no
449 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
450 * is also possible.
451 */
452static void put_object(struct kmemleak_object *object)
453{
454 if (!atomic_dec_and_test(&object->use_count))
455 return;
456
457 /* should only get here after delete_object was called */
458 WARN_ON(object->flags & OBJECT_ALLOCATED);
459
460 call_rcu(&object->rcu, free_object_rcu);
461}
462
463/*
464 * Look up an object in the prio search tree and increase its use_count.
465 */
466static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
467{
468 unsigned long flags;
469 struct kmemleak_object *object = NULL;
470
471 rcu_read_lock();
472 read_lock_irqsave(&kmemleak_lock, flags);
473 if (ptr >= min_addr && ptr < max_addr)
474 object = lookup_object(ptr, alias);
475 read_unlock_irqrestore(&kmemleak_lock, flags);
476
477 /* check whether the object is still available */
478 if (object && !get_object(object))
479 object = NULL;
480 rcu_read_unlock();
481
482 return object;
483}
484
485/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100486 * Save stack trace to the given array of MAX_TRACE size.
487 */
488static int __save_stack_trace(unsigned long *trace)
489{
490 struct stack_trace stack_trace;
491
492 stack_trace.max_entries = MAX_TRACE;
493 stack_trace.nr_entries = 0;
494 stack_trace.entries = trace;
495 stack_trace.skip = 2;
496 save_stack_trace(&stack_trace);
497
498 return stack_trace.nr_entries;
499}
500
501/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100502 * Create the metadata (struct kmemleak_object) corresponding to an allocated
503 * memory block and add it to the object_list and object_tree_root.
504 */
Catalin Marinasfd678962009-08-27 14:29:17 +0100505static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
506 int min_count, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100507{
508 unsigned long flags;
509 struct kmemleak_object *object;
510 struct prio_tree_node *node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100511
Catalin Marinas216c04b2009-06-17 18:29:02 +0100512 object = kmem_cache_alloc(object_cache, gfp & GFP_KMEMLEAK_MASK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100513 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100514 kmemleak_stop("Cannot allocate a kmemleak_object structure\n");
Catalin Marinasfd678962009-08-27 14:29:17 +0100515 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100516 }
517
518 INIT_LIST_HEAD(&object->object_list);
519 INIT_LIST_HEAD(&object->gray_list);
520 INIT_HLIST_HEAD(&object->area_list);
521 spin_lock_init(&object->lock);
522 atomic_set(&object->use_count, 1);
Catalin Marinas25873622009-07-07 10:32:58 +0100523 object->flags = OBJECT_ALLOCATED | OBJECT_NEW;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100524 object->pointer = ptr;
525 object->size = size;
526 object->min_count = min_count;
527 object->count = -1; /* no color initially */
528 object->jiffies = jiffies;
529
530 /* task information */
531 if (in_irq()) {
532 object->pid = 0;
533 strncpy(object->comm, "hardirq", sizeof(object->comm));
534 } else if (in_softirq()) {
535 object->pid = 0;
536 strncpy(object->comm, "softirq", sizeof(object->comm));
537 } else {
538 object->pid = current->pid;
539 /*
540 * There is a small chance of a race with set_task_comm(),
541 * however using get_task_comm() here may cause locking
542 * dependency issues with current->alloc_lock. In the worst
543 * case, the command line is not correct.
544 */
545 strncpy(object->comm, current->comm, sizeof(object->comm));
546 }
547
548 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100549 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100550
551 INIT_PRIO_TREE_NODE(&object->tree_node);
552 object->tree_node.start = ptr;
553 object->tree_node.last = ptr + size - 1;
554
555 write_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100556
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100557 min_addr = min(min_addr, ptr);
558 max_addr = max(max_addr, ptr + size);
559 node = prio_tree_insert(&object_tree_root, &object->tree_node);
560 /*
561 * The code calling the kernel does not yet have the pointer to the
562 * memory block to be able to free it. However, we still hold the
563 * kmemleak_lock here in case parts of the kernel started freeing
564 * random memory blocks.
565 */
566 if (node != &object->tree_node) {
Joe Perchesae281062009-06-23 14:40:26 +0100567 kmemleak_stop("Cannot insert 0x%lx into the object search tree "
568 "(already existing)\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100569 object = lookup_object(ptr, 1);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100570 spin_lock(&object->lock);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100571 dump_object_info(object);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100572 spin_unlock(&object->lock);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100573
574 goto out;
575 }
576 list_add_tail_rcu(&object->object_list, &object_list);
577out:
578 write_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinasfd678962009-08-27 14:29:17 +0100579 return object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100580}
581
582/*
583 * Remove the metadata (struct kmemleak_object) for a memory block from the
584 * object_list and object_tree_root and decrement its use_count.
585 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100586static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100587{
588 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100589
590 write_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100591 prio_tree_remove(&object_tree_root, &object->tree_node);
592 list_del_rcu(&object->object_list);
593 write_unlock_irqrestore(&kmemleak_lock, flags);
594
595 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinas53238a62009-07-07 10:33:00 +0100596 WARN_ON(atomic_read(&object->use_count) < 2);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100597
598 /*
599 * Locking here also ensures that the corresponding memory block
600 * cannot be freed when it is being scanned.
601 */
602 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100603 object->flags &= ~OBJECT_ALLOCATED;
604 spin_unlock_irqrestore(&object->lock, flags);
605 put_object(object);
606}
607
608/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100609 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
610 * delete it.
611 */
612static void delete_object_full(unsigned long ptr)
613{
614 struct kmemleak_object *object;
615
616 object = find_and_get_object(ptr, 0);
617 if (!object) {
618#ifdef DEBUG
619 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
620 ptr);
621#endif
622 return;
623 }
624 __delete_object(object);
625 put_object(object);
626}
627
628/*
629 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
630 * delete it. If the memory block is partially freed, the function may create
631 * additional metadata for the remaining parts of the block.
632 */
633static void delete_object_part(unsigned long ptr, size_t size)
634{
635 struct kmemleak_object *object;
636 unsigned long start, end;
637
638 object = find_and_get_object(ptr, 1);
639 if (!object) {
640#ifdef DEBUG
641 kmemleak_warn("Partially freeing unknown object at 0x%08lx "
642 "(size %zu)\n", ptr, size);
643#endif
644 return;
645 }
646 __delete_object(object);
647
648 /*
649 * Create one or two objects that may result from the memory block
650 * split. Note that partial freeing is only done by free_bootmem() and
651 * this happens before kmemleak_init() is called. The path below is
652 * only executed during early log recording in kmemleak_init(), so
653 * GFP_KERNEL is enough.
654 */
655 start = object->pointer;
656 end = object->pointer + object->size;
657 if (ptr > start)
658 create_object(start, ptr - start, object->min_count,
659 GFP_KERNEL);
660 if (ptr + size < end)
661 create_object(ptr + size, end - ptr - size, object->min_count,
662 GFP_KERNEL);
663
664 put_object(object);
665}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700666
667static void __paint_it(struct kmemleak_object *object, int color)
668{
669 object->min_count = color;
670 if (color == KMEMLEAK_BLACK)
671 object->flags |= OBJECT_NO_SCAN;
672}
673
674static void paint_it(struct kmemleak_object *object, int color)
675{
676 unsigned long flags;
677
678 spin_lock_irqsave(&object->lock, flags);
679 __paint_it(object, color);
680 spin_unlock_irqrestore(&object->lock, flags);
681}
682
683static void paint_ptr(unsigned long ptr, int color)
684{
685 struct kmemleak_object *object;
686
687 object = find_and_get_object(ptr, 0);
688 if (!object) {
689 kmemleak_warn("Trying to color unknown object "
690 "at 0x%08lx as %s\n", ptr,
691 (color == KMEMLEAK_GREY) ? "Grey" :
692 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
693 return;
694 }
695 paint_it(object, color);
696 put_object(object);
697}
698
Catalin Marinas53238a62009-07-07 10:33:00 +0100699/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100700 * Make a object permanently as gray-colored so that it can no longer be
701 * reported as a leak. This is used in general to mark a false positive.
702 */
703static void make_gray_object(unsigned long ptr)
704{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700705 paint_ptr(ptr, KMEMLEAK_GREY);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100706}
707
708/*
709 * Mark the object as black-colored so that it is ignored from scans and
710 * reporting.
711 */
712static void make_black_object(unsigned long ptr)
713{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700714 paint_ptr(ptr, KMEMLEAK_BLACK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100715}
716
717/*
718 * Add a scanning area to the object. If at least one such area is added,
719 * kmemleak will only scan these ranges rather than the whole memory block.
720 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000721static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100722{
723 unsigned long flags;
724 struct kmemleak_object *object;
725 struct kmemleak_scan_area *area;
726
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000727 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100728 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100729 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
730 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100731 return;
732 }
733
Catalin Marinas216c04b2009-06-17 18:29:02 +0100734 area = kmem_cache_alloc(scan_area_cache, gfp & GFP_KMEMLEAK_MASK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100735 if (!area) {
Joe Perchesae281062009-06-23 14:40:26 +0100736 kmemleak_warn("Cannot allocate a scan area\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100737 goto out;
738 }
739
740 spin_lock_irqsave(&object->lock, flags);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000741 if (ptr + size > object->pointer + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100742 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100743 dump_object_info(object);
744 kmem_cache_free(scan_area_cache, area);
745 goto out_unlock;
746 }
747
748 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000749 area->start = ptr;
750 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100751
752 hlist_add_head(&area->node, &object->area_list);
753out_unlock:
754 spin_unlock_irqrestore(&object->lock, flags);
755out:
756 put_object(object);
757}
758
759/*
760 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
761 * pointer. Such object will not be scanned by kmemleak but references to it
762 * are searched.
763 */
764static void object_no_scan(unsigned long ptr)
765{
766 unsigned long flags;
767 struct kmemleak_object *object;
768
769 object = find_and_get_object(ptr, 0);
770 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100771 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100772 return;
773 }
774
775 spin_lock_irqsave(&object->lock, flags);
776 object->flags |= OBJECT_NO_SCAN;
777 spin_unlock_irqrestore(&object->lock, flags);
778 put_object(object);
779}
780
781/*
782 * Log an early kmemleak_* call to the early_log buffer. These calls will be
783 * processed later once kmemleak is fully initialized.
784 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100785static void __init log_early(int op_type, const void *ptr, size_t size,
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000786 int min_count)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100787{
788 unsigned long flags;
789 struct early_log *log;
790
791 if (crt_early_log >= ARRAY_SIZE(early_log)) {
Catalin Marinasaddd72c2009-09-11 10:42:09 +0100792 pr_warning("Early log buffer exceeded, "
793 "please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n");
Catalin Marinasa9d90582009-06-25 10:16:11 +0100794 kmemleak_disable();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100795 return;
796 }
797
798 /*
799 * There is no need for locking since the kernel is still in UP mode
800 * at this stage. Disabling the IRQs is enough.
801 */
802 local_irq_save(flags);
803 log = &early_log[crt_early_log];
804 log->op_type = op_type;
805 log->ptr = ptr;
806 log->size = size;
807 log->min_count = min_count;
Catalin Marinasfd678962009-08-27 14:29:17 +0100808 if (op_type == KMEMLEAK_ALLOC)
809 log->trace_len = __save_stack_trace(log->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100810 crt_early_log++;
811 local_irq_restore(flags);
812}
813
814/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100815 * Log an early allocated block and populate the stack trace.
816 */
817static void early_alloc(struct early_log *log)
818{
819 struct kmemleak_object *object;
820 unsigned long flags;
821 int i;
822
823 if (!atomic_read(&kmemleak_enabled) || !log->ptr || IS_ERR(log->ptr))
824 return;
825
826 /*
827 * RCU locking needed to ensure object is not freed via put_object().
828 */
829 rcu_read_lock();
830 object = create_object((unsigned long)log->ptr, log->size,
Tetsuo Handac1bcd6b2009-10-09 10:39:24 +0100831 log->min_count, GFP_ATOMIC);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100832 if (!object)
833 goto out;
Catalin Marinasfd678962009-08-27 14:29:17 +0100834 spin_lock_irqsave(&object->lock, flags);
835 for (i = 0; i < log->trace_len; i++)
836 object->trace[i] = log->trace[i];
837 object->trace_len = log->trace_len;
838 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100839out:
Catalin Marinasfd678962009-08-27 14:29:17 +0100840 rcu_read_unlock();
841}
842
843/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100844 * Memory allocation function callback. This function is called from the
845 * kernel allocators when a new block is allocated (kmem_cache_alloc, kmalloc,
846 * vmalloc etc.).
847 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100848void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
849 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100850{
851 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
852
853 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
854 create_object((unsigned long)ptr, size, min_count, gfp);
855 else if (atomic_read(&kmemleak_early_log))
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000856 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100857}
858EXPORT_SYMBOL_GPL(kmemleak_alloc);
859
860/*
861 * Memory freeing function callback. This function is called from the kernel
862 * allocators when a block is freed (kmem_cache_free, kfree, vfree etc.).
863 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100864void __ref kmemleak_free(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100865{
866 pr_debug("%s(0x%p)\n", __func__, ptr);
867
868 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +0100869 delete_object_full((unsigned long)ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100870 else if (atomic_read(&kmemleak_early_log))
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000871 log_early(KMEMLEAK_FREE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100872}
873EXPORT_SYMBOL_GPL(kmemleak_free);
874
875/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100876 * Partial memory freeing function callback. This function is usually called
877 * from bootmem allocator when (part of) a memory block is freed.
878 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100879void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +0100880{
881 pr_debug("%s(0x%p)\n", __func__, ptr);
882
883 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
884 delete_object_part((unsigned long)ptr, size);
885 else if (atomic_read(&kmemleak_early_log))
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000886 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100887}
888EXPORT_SYMBOL_GPL(kmemleak_free_part);
889
890/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100891 * Mark an already allocated memory block as a false positive. This will cause
892 * the block to no longer be reported as leak and always be scanned.
893 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100894void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100895{
896 pr_debug("%s(0x%p)\n", __func__, ptr);
897
898 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
899 make_gray_object((unsigned long)ptr);
900 else if (atomic_read(&kmemleak_early_log))
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000901 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100902}
903EXPORT_SYMBOL(kmemleak_not_leak);
904
905/*
906 * Ignore a memory block. This is usually done when it is known that the
907 * corresponding block is not a leak and does not contain any references to
908 * other allocated memory blocks.
909 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100910void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100911{
912 pr_debug("%s(0x%p)\n", __func__, ptr);
913
914 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
915 make_black_object((unsigned long)ptr);
916 else if (atomic_read(&kmemleak_early_log))
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000917 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100918}
919EXPORT_SYMBOL(kmemleak_ignore);
920
921/*
922 * Limit the range to be scanned in an allocated memory block.
923 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000924void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100925{
926 pr_debug("%s(0x%p)\n", __func__, ptr);
927
928 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000929 add_scan_area((unsigned long)ptr, size, gfp);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100930 else if (atomic_read(&kmemleak_early_log))
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000931 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100932}
933EXPORT_SYMBOL(kmemleak_scan_area);
934
935/*
936 * Inform kmemleak not to scan the given memory block.
937 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100938void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100939{
940 pr_debug("%s(0x%p)\n", __func__, ptr);
941
942 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
943 object_no_scan((unsigned long)ptr);
944 else if (atomic_read(&kmemleak_early_log))
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000945 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100946}
947EXPORT_SYMBOL(kmemleak_no_scan);
948
949/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100950 * Memory scanning is a long process and it needs to be interruptable. This
951 * function checks whether such interrupt condition occured.
952 */
953static int scan_should_stop(void)
954{
955 if (!atomic_read(&kmemleak_enabled))
956 return 1;
957
958 /*
959 * This function may be called from either process or kthread context,
960 * hence the need to check for both stop conditions.
961 */
962 if (current->mm)
963 return signal_pending(current);
964 else
965 return kthread_should_stop();
966
967 return 0;
968}
969
970/*
971 * Scan a memory block (exclusive range) for valid pointers and add those
972 * found to the gray list.
973 */
974static void scan_block(void *_start, void *_end,
Catalin Marinas4b8a9672009-07-07 10:32:56 +0100975 struct kmemleak_object *scanned, int allow_resched)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100976{
977 unsigned long *ptr;
978 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
979 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
980
981 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100982 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +0100983 unsigned long flags;
984 unsigned long pointer;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100985
Catalin Marinas4b8a9672009-07-07 10:32:56 +0100986 if (allow_resched)
987 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100988 if (scan_should_stop())
989 break;
990
Pekka Enberg8e019362009-08-27 14:50:00 +0100991 /* don't scan uninitialized memory */
992 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
993 BYTES_PER_POINTER))
994 continue;
995
996 pointer = *ptr;
997
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100998 object = find_and_get_object(pointer, 1);
999 if (!object)
1000 continue;
1001 if (object == scanned) {
1002 /* self referenced, ignore */
1003 put_object(object);
1004 continue;
1005 }
1006
1007 /*
1008 * Avoid the lockdep recursive warning on object->lock being
1009 * previously acquired in scan_object(). These locks are
1010 * enclosed by scan_mutex.
1011 */
1012 spin_lock_irqsave_nested(&object->lock, flags,
1013 SINGLE_DEPTH_NESTING);
1014 if (!color_white(object)) {
1015 /* non-orphan, ignored or new */
1016 spin_unlock_irqrestore(&object->lock, flags);
1017 put_object(object);
1018 continue;
1019 }
1020
1021 /*
1022 * Increase the object's reference count (number of pointers
1023 * to the memory block). If this count reaches the required
1024 * minimum, the object's color will become gray and it will be
1025 * added to the gray_list.
1026 */
1027 object->count++;
Catalin Marinas0587da42009-10-28 13:33:11 +00001028 if (color_gray(object)) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001029 list_add_tail(&object->gray_list, &gray_list);
Catalin Marinas0587da42009-10-28 13:33:11 +00001030 spin_unlock_irqrestore(&object->lock, flags);
1031 continue;
1032 }
1033
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001034 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0587da42009-10-28 13:33:11 +00001035 put_object(object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001036 }
1037}
1038
1039/*
1040 * Scan a memory block corresponding to a kmemleak_object. A condition is
1041 * that object->use_count >= 1.
1042 */
1043static void scan_object(struct kmemleak_object *object)
1044{
1045 struct kmemleak_scan_area *area;
1046 struct hlist_node *elem;
1047 unsigned long flags;
1048
1049 /*
1050 * Once the object->lock is aquired, the corresponding memory block
1051 * cannot be freed (the same lock is aquired in delete_object).
1052 */
1053 spin_lock_irqsave(&object->lock, flags);
1054 if (object->flags & OBJECT_NO_SCAN)
1055 goto out;
1056 if (!(object->flags & OBJECT_ALLOCATED))
1057 /* already freed object */
1058 goto out;
Catalin Marinasaf986032009-08-27 14:29:12 +01001059 if (hlist_empty(&object->area_list)) {
1060 void *start = (void *)object->pointer;
1061 void *end = (void *)(object->pointer + object->size);
1062
1063 while (start < end && (object->flags & OBJECT_ALLOCATED) &&
1064 !(object->flags & OBJECT_NO_SCAN)) {
1065 scan_block(start, min(start + MAX_SCAN_SIZE, end),
1066 object, 0);
1067 start += MAX_SCAN_SIZE;
1068
1069 spin_unlock_irqrestore(&object->lock, flags);
1070 cond_resched();
1071 spin_lock_irqsave(&object->lock, flags);
1072 }
1073 } else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001074 hlist_for_each_entry(area, elem, &object->area_list, node)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001075 scan_block((void *)area->start,
1076 (void *)(area->start + area->size),
1077 object, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001078out:
1079 spin_unlock_irqrestore(&object->lock, flags);
1080}
1081
1082/*
1083 * Scan data sections and all the referenced memory blocks allocated via the
1084 * kernel's standard allocators. This function must be called with the
1085 * scan_mutex held.
1086 */
1087static void kmemleak_scan(void)
1088{
1089 unsigned long flags;
1090 struct kmemleak_object *object, *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001091 int i;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001092 int new_leaks = 0;
Catalin Marinas25873622009-07-07 10:32:58 +01001093 int gray_list_pass = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001094
Catalin Marinasacf49682009-06-26 17:38:29 +01001095 jiffies_last_scan = jiffies;
1096
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001097 /* prepare the kmemleak_object's */
1098 rcu_read_lock();
1099 list_for_each_entry_rcu(object, &object_list, object_list) {
1100 spin_lock_irqsave(&object->lock, flags);
1101#ifdef DEBUG
1102 /*
1103 * With a few exceptions there should be a maximum of
1104 * 1 reference to any object at this point.
1105 */
1106 if (atomic_read(&object->use_count) > 1) {
Joe Perchesae281062009-06-23 14:40:26 +01001107 pr_debug("object->use_count = %d\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001108 atomic_read(&object->use_count));
1109 dump_object_info(object);
1110 }
1111#endif
1112 /* reset the reference count (whiten the object) */
1113 object->count = 0;
Catalin Marinas25873622009-07-07 10:32:58 +01001114 object->flags &= ~OBJECT_NEW;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001115 if (color_gray(object) && get_object(object))
1116 list_add_tail(&object->gray_list, &gray_list);
1117
1118 spin_unlock_irqrestore(&object->lock, flags);
1119 }
1120 rcu_read_unlock();
1121
1122 /* data/bss scanning */
Catalin Marinas4b8a9672009-07-07 10:32:56 +01001123 scan_block(_sdata, _edata, NULL, 1);
1124 scan_block(__bss_start, __bss_stop, NULL, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001125
1126#ifdef CONFIG_SMP
1127 /* per-cpu sections scanning */
1128 for_each_possible_cpu(i)
1129 scan_block(__per_cpu_start + per_cpu_offset(i),
Catalin Marinas4b8a9672009-07-07 10:32:56 +01001130 __per_cpu_end + per_cpu_offset(i), NULL, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001131#endif
1132
1133 /*
1134 * Struct page scanning for each node. The code below is not yet safe
1135 * with MEMORY_HOTPLUG.
1136 */
1137 for_each_online_node(i) {
1138 pg_data_t *pgdat = NODE_DATA(i);
1139 unsigned long start_pfn = pgdat->node_start_pfn;
1140 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
1141 unsigned long pfn;
1142
1143 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1144 struct page *page;
1145
1146 if (!pfn_valid(pfn))
1147 continue;
1148 page = pfn_to_page(pfn);
1149 /* only scan if page is in use */
1150 if (page_count(page) == 0)
1151 continue;
Catalin Marinas4b8a9672009-07-07 10:32:56 +01001152 scan_block(page, page + 1, NULL, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001153 }
1154 }
1155
1156 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001157 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001158 */
1159 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001160 struct task_struct *p, *g;
1161
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001162 read_lock(&tasklist_lock);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001163 do_each_thread(g, p) {
1164 scan_block(task_stack_page(p), task_stack_page(p) +
1165 THREAD_SIZE, NULL, 0);
1166 } while_each_thread(g, p);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001167 read_unlock(&tasklist_lock);
1168 }
1169
1170 /*
1171 * Scan the objects already referenced from the sections scanned
1172 * above. More objects will be referenced and, if there are no memory
1173 * leaks, all the objects will be scanned. The list traversal is safe
1174 * for both tail additions and removals from inside the loop. The
1175 * kmemleak objects cannot be freed from outside the loop because their
1176 * use_count was increased.
1177 */
Catalin Marinas25873622009-07-07 10:32:58 +01001178repeat:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001179 object = list_entry(gray_list.next, typeof(*object), gray_list);
1180 while (&object->gray_list != &gray_list) {
Ingo Molnar57d81f62009-07-01 09:43:53 +02001181 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001182
1183 /* may add new objects to the list */
1184 if (!scan_should_stop())
1185 scan_object(object);
1186
1187 tmp = list_entry(object->gray_list.next, typeof(*object),
1188 gray_list);
1189
1190 /* remove the object from the list and release it */
1191 list_del(&object->gray_list);
1192 put_object(object);
1193
1194 object = tmp;
1195 }
Catalin Marinas25873622009-07-07 10:32:58 +01001196
1197 if (scan_should_stop() || ++gray_list_pass >= GRAY_LIST_PASSES)
1198 goto scan_end;
1199
1200 /*
1201 * Check for new objects allocated during this scanning and add them
1202 * to the gray list.
1203 */
1204 rcu_read_lock();
1205 list_for_each_entry_rcu(object, &object_list, object_list) {
1206 spin_lock_irqsave(&object->lock, flags);
1207 if ((object->flags & OBJECT_NEW) && !color_black(object) &&
1208 get_object(object)) {
1209 object->flags &= ~OBJECT_NEW;
1210 list_add_tail(&object->gray_list, &gray_list);
1211 }
1212 spin_unlock_irqrestore(&object->lock, flags);
1213 }
1214 rcu_read_unlock();
1215
1216 if (!list_empty(&gray_list))
1217 goto repeat;
1218
1219scan_end:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001220 WARN_ON(!list_empty(&gray_list));
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001221
1222 /*
Catalin Marinas25873622009-07-07 10:32:58 +01001223 * If scanning was stopped or new objects were being allocated at a
1224 * higher rate than gray list scanning, do not report any new
1225 * unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001226 */
Catalin Marinas25873622009-07-07 10:32:58 +01001227 if (scan_should_stop() || gray_list_pass >= GRAY_LIST_PASSES)
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001228 return;
1229
1230 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001231 * Scanning result reporting.
1232 */
1233 rcu_read_lock();
1234 list_for_each_entry_rcu(object, &object_list, object_list) {
1235 spin_lock_irqsave(&object->lock, flags);
1236 if (unreferenced_object(object) &&
1237 !(object->flags & OBJECT_REPORTED)) {
1238 object->flags |= OBJECT_REPORTED;
1239 new_leaks++;
1240 }
1241 spin_unlock_irqrestore(&object->lock, flags);
1242 }
1243 rcu_read_unlock();
1244
1245 if (new_leaks)
1246 pr_info("%d new suspected memory leaks (see "
1247 "/sys/kernel/debug/kmemleak)\n", new_leaks);
1248
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001249}
1250
1251/*
1252 * Thread function performing automatic memory scanning. Unreferenced objects
1253 * at the end of a memory scan are reported but only the first time.
1254 */
1255static int kmemleak_scan_thread(void *arg)
1256{
1257 static int first_run = 1;
1258
Joe Perchesae281062009-06-23 14:40:26 +01001259 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001260 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001261
1262 /*
1263 * Wait before the first scan to allow the system to fully initialize.
1264 */
1265 if (first_run) {
1266 first_run = 0;
1267 ssleep(SECS_FIRST_SCAN);
1268 }
1269
1270 while (!kthread_should_stop()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001271 signed long timeout = jiffies_scan_wait;
1272
1273 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001274 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001275 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001276
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001277 /* wait before the next scan */
1278 while (timeout && !kthread_should_stop())
1279 timeout = schedule_timeout_interruptible(timeout);
1280 }
1281
Joe Perchesae281062009-06-23 14:40:26 +01001282 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001283
1284 return 0;
1285}
1286
1287/*
1288 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001289 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001290 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001291static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001292{
1293 if (scan_thread)
1294 return;
1295 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1296 if (IS_ERR(scan_thread)) {
Joe Perchesae281062009-06-23 14:40:26 +01001297 pr_warning("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001298 scan_thread = NULL;
1299 }
1300}
1301
1302/*
1303 * Stop the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001304 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001305 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001306static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001307{
1308 if (scan_thread) {
1309 kthread_stop(scan_thread);
1310 scan_thread = NULL;
1311 }
1312}
1313
1314/*
1315 * Iterate over the object_list and return the first valid object at or after
1316 * the required position with its use_count incremented. The function triggers
1317 * a memory scanning when the pos argument points to the first position.
1318 */
1319static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1320{
1321 struct kmemleak_object *object;
1322 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001323 int err;
1324
1325 err = mutex_lock_interruptible(&scan_mutex);
1326 if (err < 0)
1327 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001328
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001329 rcu_read_lock();
1330 list_for_each_entry_rcu(object, &object_list, object_list) {
1331 if (n-- > 0)
1332 continue;
1333 if (get_object(object))
1334 goto out;
1335 }
1336 object = NULL;
1337out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001338 return object;
1339}
1340
1341/*
1342 * Return the next object in the object_list. The function decrements the
1343 * use_count of the previous object and increases that of the next one.
1344 */
1345static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1346{
1347 struct kmemleak_object *prev_obj = v;
1348 struct kmemleak_object *next_obj = NULL;
1349 struct list_head *n = &prev_obj->object_list;
1350
1351 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001352
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001353 list_for_each_continue_rcu(n, &object_list) {
1354 next_obj = list_entry(n, struct kmemleak_object, object_list);
1355 if (get_object(next_obj))
1356 break;
1357 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001358
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001359 put_object(prev_obj);
1360 return next_obj;
1361}
1362
1363/*
1364 * Decrement the use_count of the last object required, if any.
1365 */
1366static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1367{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001368 if (!IS_ERR(v)) {
1369 /*
1370 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1371 * waiting was interrupted, so only release it if !IS_ERR.
1372 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001373 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001374 mutex_unlock(&scan_mutex);
1375 if (v)
1376 put_object(v);
1377 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001378}
1379
1380/*
1381 * Print the information for an unreferenced object to the seq file.
1382 */
1383static int kmemleak_seq_show(struct seq_file *seq, void *v)
1384{
1385 struct kmemleak_object *object = v;
1386 unsigned long flags;
1387
1388 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001389 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001390 print_unreferenced(seq, object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001391 spin_unlock_irqrestore(&object->lock, flags);
1392 return 0;
1393}
1394
1395static const struct seq_operations kmemleak_seq_ops = {
1396 .start = kmemleak_seq_start,
1397 .next = kmemleak_seq_next,
1398 .stop = kmemleak_seq_stop,
1399 .show = kmemleak_seq_show,
1400};
1401
1402static int kmemleak_open(struct inode *inode, struct file *file)
1403{
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001404 if (!atomic_read(&kmemleak_enabled))
1405 return -EBUSY;
1406
Catalin Marinasb87324d2009-07-07 10:32:58 +01001407 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001408}
1409
1410static int kmemleak_release(struct inode *inode, struct file *file)
1411{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001412 return seq_release(inode, file);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001413}
1414
Catalin Marinas189d84e2009-08-27 14:29:15 +01001415static int dump_str_object_info(const char *str)
1416{
1417 unsigned long flags;
1418 struct kmemleak_object *object;
1419 unsigned long addr;
1420
1421 addr= simple_strtoul(str, NULL, 0);
1422 object = find_and_get_object(addr, 0);
1423 if (!object) {
1424 pr_info("Unknown object at 0x%08lx\n", addr);
1425 return -EINVAL;
1426 }
1427
1428 spin_lock_irqsave(&object->lock, flags);
1429 dump_object_info(object);
1430 spin_unlock_irqrestore(&object->lock, flags);
1431
1432 put_object(object);
1433 return 0;
1434}
1435
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001436/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001437 * We use grey instead of black to ensure we can do future scans on the same
1438 * objects. If we did not do future scans these black objects could
1439 * potentially contain references to newly allocated objects in the future and
1440 * we'd end up with false positives.
1441 */
1442static void kmemleak_clear(void)
1443{
1444 struct kmemleak_object *object;
1445 unsigned long flags;
1446
1447 rcu_read_lock();
1448 list_for_each_entry_rcu(object, &object_list, object_list) {
1449 spin_lock_irqsave(&object->lock, flags);
1450 if ((object->flags & OBJECT_REPORTED) &&
1451 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001452 __paint_it(object, KMEMLEAK_GREY);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001453 spin_unlock_irqrestore(&object->lock, flags);
1454 }
1455 rcu_read_unlock();
1456}
1457
1458/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001459 * File write operation to configure kmemleak at run-time. The following
1460 * commands can be written to the /sys/kernel/debug/kmemleak file:
1461 * off - disable kmemleak (irreversible)
1462 * stack=on - enable the task stacks scanning
1463 * stack=off - disable the tasks stacks scanning
1464 * scan=on - start the automatic memory scanning thread
1465 * scan=off - stop the automatic memory scanning thread
1466 * scan=... - set the automatic memory scanning period in seconds (0 to
1467 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001468 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001469 * clear - mark all current reported unreferenced kmemleak objects as
1470 * grey to ignore printing them
Catalin Marinas189d84e2009-08-27 14:29:15 +01001471 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001472 */
1473static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1474 size_t size, loff_t *ppos)
1475{
1476 char buf[64];
1477 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001478 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001479
1480 buf_size = min(size, (sizeof(buf) - 1));
1481 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1482 return -EFAULT;
1483 buf[buf_size] = 0;
1484
Catalin Marinasb87324d2009-07-07 10:32:58 +01001485 ret = mutex_lock_interruptible(&scan_mutex);
1486 if (ret < 0)
1487 return ret;
1488
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001489 if (strncmp(buf, "off", 3) == 0)
1490 kmemleak_disable();
1491 else if (strncmp(buf, "stack=on", 8) == 0)
1492 kmemleak_stack_scan = 1;
1493 else if (strncmp(buf, "stack=off", 9) == 0)
1494 kmemleak_stack_scan = 0;
1495 else if (strncmp(buf, "scan=on", 7) == 0)
1496 start_scan_thread();
1497 else if (strncmp(buf, "scan=off", 8) == 0)
1498 stop_scan_thread();
1499 else if (strncmp(buf, "scan=", 5) == 0) {
1500 unsigned long secs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001501
Catalin Marinasb87324d2009-07-07 10:32:58 +01001502 ret = strict_strtoul(buf + 5, 0, &secs);
1503 if (ret < 0)
1504 goto out;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001505 stop_scan_thread();
1506 if (secs) {
1507 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1508 start_scan_thread();
1509 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001510 } else if (strncmp(buf, "scan", 4) == 0)
1511 kmemleak_scan();
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001512 else if (strncmp(buf, "clear", 5) == 0)
1513 kmemleak_clear();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001514 else if (strncmp(buf, "dump=", 5) == 0)
1515 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001516 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001517 ret = -EINVAL;
1518
1519out:
1520 mutex_unlock(&scan_mutex);
1521 if (ret < 0)
1522 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001523
1524 /* ignore the rest of the buffer, only one command at a time */
1525 *ppos += size;
1526 return size;
1527}
1528
1529static const struct file_operations kmemleak_fops = {
1530 .owner = THIS_MODULE,
1531 .open = kmemleak_open,
1532 .read = seq_read,
1533 .write = kmemleak_write,
1534 .llseek = seq_lseek,
1535 .release = kmemleak_release,
1536};
1537
1538/*
1539 * Perform the freeing of the kmemleak internal objects after waiting for any
1540 * current memory scan to complete.
1541 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001542static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001543{
1544 struct kmemleak_object *object;
1545
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001546 mutex_lock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001547 stop_scan_thread();
1548
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001549 rcu_read_lock();
1550 list_for_each_entry_rcu(object, &object_list, object_list)
Catalin Marinas53238a62009-07-07 10:33:00 +01001551 delete_object_full(object->pointer);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001552 rcu_read_unlock();
1553 mutex_unlock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001554}
1555
Catalin Marinas179a8102009-09-07 10:14:42 +01001556static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001557
1558/*
1559 * Disable kmemleak. No memory allocation/freeing will be traced once this
1560 * function is called. Disabling kmemleak is an irreversible operation.
1561 */
1562static void kmemleak_disable(void)
1563{
1564 /* atomically check whether it was already invoked */
1565 if (atomic_cmpxchg(&kmemleak_error, 0, 1))
1566 return;
1567
1568 /* stop any memory operation tracing */
1569 atomic_set(&kmemleak_early_log, 0);
1570 atomic_set(&kmemleak_enabled, 0);
1571
1572 /* check whether it is too early for a kernel thread */
1573 if (atomic_read(&kmemleak_initialized))
Catalin Marinas179a8102009-09-07 10:14:42 +01001574 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001575
1576 pr_info("Kernel memory leak detector disabled\n");
1577}
1578
1579/*
1580 * Allow boot-time kmemleak disabling (enabled by default).
1581 */
1582static int kmemleak_boot_config(char *str)
1583{
1584 if (!str)
1585 return -EINVAL;
1586 if (strcmp(str, "off") == 0)
1587 kmemleak_disable();
1588 else if (strcmp(str, "on") != 0)
1589 return -EINVAL;
1590 return 0;
1591}
1592early_param("kmemleak", kmemleak_boot_config);
1593
1594/*
Catalin Marinas20301172009-06-17 18:29:04 +01001595 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001596 */
1597void __init kmemleak_init(void)
1598{
1599 int i;
1600 unsigned long flags;
1601
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001602 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
1603 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
1604
1605 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
1606 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
1607 INIT_PRIO_TREE_ROOT(&object_tree_root);
1608
1609 /* the kernel is still in UP mode, so disabling the IRQs is enough */
1610 local_irq_save(flags);
1611 if (!atomic_read(&kmemleak_error)) {
1612 atomic_set(&kmemleak_enabled, 1);
1613 atomic_set(&kmemleak_early_log, 0);
1614 }
1615 local_irq_restore(flags);
1616
1617 /*
1618 * This is the point where tracking allocations is safe. Automatic
1619 * scanning is started during the late initcall. Add the early logged
1620 * callbacks to the kmemleak infrastructure.
1621 */
1622 for (i = 0; i < crt_early_log; i++) {
1623 struct early_log *log = &early_log[i];
1624
1625 switch (log->op_type) {
1626 case KMEMLEAK_ALLOC:
Catalin Marinasfd678962009-08-27 14:29:17 +01001627 early_alloc(log);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001628 break;
1629 case KMEMLEAK_FREE:
1630 kmemleak_free(log->ptr);
1631 break;
Catalin Marinas53238a62009-07-07 10:33:00 +01001632 case KMEMLEAK_FREE_PART:
1633 kmemleak_free_part(log->ptr, log->size);
1634 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001635 case KMEMLEAK_NOT_LEAK:
1636 kmemleak_not_leak(log->ptr);
1637 break;
1638 case KMEMLEAK_IGNORE:
1639 kmemleak_ignore(log->ptr);
1640 break;
1641 case KMEMLEAK_SCAN_AREA:
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001642 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001643 break;
1644 case KMEMLEAK_NO_SCAN:
1645 kmemleak_no_scan(log->ptr);
1646 break;
1647 default:
1648 WARN_ON(1);
1649 }
1650 }
1651}
1652
1653/*
1654 * Late initialization function.
1655 */
1656static int __init kmemleak_late_init(void)
1657{
1658 struct dentry *dentry;
1659
1660 atomic_set(&kmemleak_initialized, 1);
1661
1662 if (atomic_read(&kmemleak_error)) {
1663 /*
1664 * Some error occured and kmemleak was disabled. There is a
1665 * small chance that kmemleak_disable() was called immediately
1666 * after setting kmemleak_initialized and we may end up with
1667 * two clean-up threads but serialized by scan_mutex.
1668 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001669 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001670 return -ENOMEM;
1671 }
1672
1673 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
1674 &kmemleak_fops);
1675 if (!dentry)
Joe Perchesae281062009-06-23 14:40:26 +01001676 pr_warning("Failed to create the debugfs kmemleak file\n");
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001677 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001678 start_scan_thread();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001679 mutex_unlock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001680
1681 pr_info("Kernel memory leak detector initialized\n");
1682
1683 return 0;
1684}
1685late_initcall(kmemleak_late_init);