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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
Michel Lespinasse85d3a312012-10-08 16:31:27 -070032 * blocks. The object_tree_root is a red black tree used to look-up
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010033 * 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 *
Catalin Marinas93ada572015-06-24 16:58:37 -070056 * Locks and mutexes are acquired/nested in the following order:
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070057 *
Catalin Marinas93ada572015-06-24 16:58:37 -070058 * 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.
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070062 *
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010063 * 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
Joe Perchesae281062009-06-23 14:40:26 +010071#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
72
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010073#include <linux/init.h>
74#include <linux/kernel.h>
75#include <linux/list.h>
76#include <linux/sched.h>
77#include <linux/jiffies.h>
78#include <linux/delay.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040079#include <linux/export.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010080#include <linux/kthread.h>
Michel Lespinasse85d3a312012-10-08 16:31:27 -070081#include <linux/rbtree.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010082#include <linux/fs.h>
83#include <linux/debugfs.h>
84#include <linux/seq_file.h>
85#include <linux/cpumask.h>
86#include <linux/spinlock.h>
87#include <linux/mutex.h>
88#include <linux/rcupdate.h>
89#include <linux/stacktrace.h>
90#include <linux/cache.h>
91#include <linux/percpu.h>
92#include <linux/hardirq.h>
93#include <linux/mmzone.h>
94#include <linux/slab.h>
95#include <linux/thread_info.h>
96#include <linux/err.h>
97#include <linux/uaccess.h>
98#include <linux/string.h>
99#include <linux/nodemask.h>
100#include <linux/mm.h>
Catalin Marinas179a8102009-09-07 10:14:42 +0100101#include <linux/workqueue.h>
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000102#include <linux/crc32.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100103
104#include <asm/sections.h>
105#include <asm/processor.h>
Arun Sharma600634972011-07-26 16:09:06 -0700106#include <linux/atomic.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100107
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -0800108#include <linux/kasan.h>
Pekka Enberg8e019362009-08-27 14:50:00 +0100109#include <linux/kmemcheck.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100110#include <linux/kmemleak.h>
Laura Abbott029aeff2011-11-15 23:49:09 +0000111#include <linux/memory_hotplug.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100112
113/*
114 * Kmemleak configuration and common defines.
115 */
116#define MAX_TRACE 16 /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100117#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100118#define SECS_FIRST_SCAN 60 /* delay before the first scan */
119#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
Catalin Marinasaf986032009-08-27 14:29:12 +0100120#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100121
122#define BYTES_PER_POINTER sizeof(void *)
123
Catalin Marinas216c04b2009-06-17 18:29:02 +0100124/* GFP bitmask for kmemleak internal allocations */
Vladimir Davydov20b5c302016-01-14 15:18:08 -0800125#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000126 __GFP_NORETRY | __GFP_NOMEMALLOC | \
127 __GFP_NOWARN)
Catalin Marinas216c04b2009-06-17 18:29:02 +0100128
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100129/* scanning area inside a memory block */
130struct kmemleak_scan_area {
131 struct hlist_node node;
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000132 unsigned long start;
133 size_t size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100134};
135
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700136#define KMEMLEAK_GREY 0
137#define KMEMLEAK_BLACK -1
138
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100139/*
140 * Structure holding the metadata for each allocated memory block.
141 * Modifications to such objects should be made while holding the
142 * object->lock. Insertions or deletions from object_list, gray_list or
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700143 * rb_node are already protected by the corresponding locks or mutex (see
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100144 * the notes on locking above). These objects are reference-counted
145 * (use_count) and freed using the RCU mechanism.
146 */
147struct kmemleak_object {
148 spinlock_t lock;
149 unsigned long flags; /* object status flags */
150 struct list_head object_list;
151 struct list_head gray_list;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700152 struct rb_node rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100153 struct rcu_head rcu; /* object_list lockless traversal */
154 /* object usage count; object freed when use_count == 0 */
155 atomic_t use_count;
156 unsigned long pointer;
157 size_t size;
158 /* minimum number of a pointers found before it is considered leak */
159 int min_count;
160 /* the total number of pointers found pointing to this object */
161 int count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000162 /* checksum for detecting modified objects */
163 u32 checksum;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100164 /* memory ranges to be scanned inside an object (empty for all) */
165 struct hlist_head area_list;
166 unsigned long trace[MAX_TRACE];
167 unsigned int trace_len;
168 unsigned long jiffies; /* creation timestamp */
169 pid_t pid; /* pid of the current task */
170 char comm[TASK_COMM_LEN]; /* executable name */
171};
172
173/* flag representing the memory block allocation status */
174#define OBJECT_ALLOCATED (1 << 0)
175/* flag set after the first reporting of an unreference object */
176#define OBJECT_REPORTED (1 << 1)
177/* flag set to not scan the object */
178#define OBJECT_NO_SCAN (1 << 2)
179
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100180/* number of bytes to print per line; must be 16 or 32 */
181#define HEX_ROW_SIZE 16
182/* number of bytes to print at a time (1, 2, 4, 8) */
183#define HEX_GROUP_SIZE 1
184/* include ASCII after the hex output */
185#define HEX_ASCII 1
186/* max number of lines to be printed */
187#define HEX_MAX_LINES 2
188
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100189/* the list of all allocated objects */
190static LIST_HEAD(object_list);
191/* the list of gray-colored objects (see color_gray comment below) */
192static LIST_HEAD(gray_list);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700193/* search tree for object boundaries */
194static struct rb_root object_tree_root = RB_ROOT;
195/* rw_lock protecting the access to object_list and object_tree_root */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100196static DEFINE_RWLOCK(kmemleak_lock);
197
198/* allocation caches for kmemleak internal data */
199static struct kmem_cache *object_cache;
200static struct kmem_cache *scan_area_cache;
201
202/* set if tracing memory operations is enabled */
Li Zefan8910ae82014-04-03 14:46:29 -0700203static int kmemleak_enabled;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700204/* same as above but only for the kmemleak_free() callback */
205static int kmemleak_free_enabled;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100206/* set in the late_initcall if there were no errors */
Li Zefan8910ae82014-04-03 14:46:29 -0700207static int kmemleak_initialized;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100208/* enables or disables early logging of the memory operations */
Li Zefan8910ae82014-04-03 14:46:29 -0700209static int kmemleak_early_log = 1;
Catalin Marinas5f790202011-09-28 12:17:03 +0100210/* set if a kmemleak warning was issued */
Li Zefan8910ae82014-04-03 14:46:29 -0700211static int kmemleak_warning;
Catalin Marinas5f790202011-09-28 12:17:03 +0100212/* set if a fatal kmemleak error has occurred */
Li Zefan8910ae82014-04-03 14:46:29 -0700213static int kmemleak_error;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100214
215/* minimum and maximum address that may be valid pointers */
216static unsigned long min_addr = ULONG_MAX;
217static unsigned long max_addr;
218
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100219static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100220/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100221static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100222static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100223/* delay between automatic memory scannings */
224static signed long jiffies_scan_wait;
225/* enables or disables the task stacks scanning */
Catalin Marinase0a2a162009-06-26 17:38:25 +0100226static int kmemleak_stack_scan = 1;
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100227/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100228static DEFINE_MUTEX(scan_mutex);
Jason Baronab0155a2010-07-19 11:54:17 +0100229/* setting kmemleak=on, will set this var, skipping the disable */
230static int kmemleak_skip_disable;
Li Zefandc9b3f42014-04-03 14:46:26 -0700231/* If there are leaks that can be reported */
232static bool kmemleak_found_leaks;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100233
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100234/*
Catalin Marinas20301172009-06-17 18:29:04 +0100235 * Early object allocation/freeing logging. Kmemleak is initialized after the
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100236 * kernel allocator. However, both the kernel allocator and kmemleak may
Catalin Marinas20301172009-06-17 18:29:04 +0100237 * allocate memory blocks which need to be tracked. Kmemleak defines an
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100238 * arbitrary buffer to hold the allocation/freeing information before it is
239 * fully initialized.
240 */
241
242/* kmemleak operation type for early logging */
243enum {
244 KMEMLEAK_ALLOC,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100245 KMEMLEAK_ALLOC_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100246 KMEMLEAK_FREE,
Catalin Marinas53238a62009-07-07 10:33:00 +0100247 KMEMLEAK_FREE_PART,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100248 KMEMLEAK_FREE_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100249 KMEMLEAK_NOT_LEAK,
250 KMEMLEAK_IGNORE,
251 KMEMLEAK_SCAN_AREA,
252 KMEMLEAK_NO_SCAN
253};
254
255/*
256 * Structure holding the information passed to kmemleak callbacks during the
257 * early logging.
258 */
259struct early_log {
260 int op_type; /* kmemleak operation type */
261 const void *ptr; /* allocated/freed memory block */
262 size_t size; /* memory block size */
263 int min_count; /* minimum reference count */
Catalin Marinasfd678962009-08-27 14:29:17 +0100264 unsigned long trace[MAX_TRACE]; /* stack trace */
265 unsigned int trace_len; /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100266};
267
268/* early logging buffer and current position */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100269static struct early_log
270 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
271static int crt_early_log __initdata;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100272
273static void kmemleak_disable(void);
274
275/*
276 * Print a warning and dump the stack trace.
277 */
Catalin Marinas5f790202011-09-28 12:17:03 +0100278#define kmemleak_warn(x...) do { \
279 pr_warning(x); \
280 dump_stack(); \
Li Zefan8910ae82014-04-03 14:46:29 -0700281 kmemleak_warning = 1; \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100282} while (0)
283
284/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300285 * Macro invoked when a serious kmemleak condition occurred and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100286 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100287 * tracing no longer available.
288 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100289#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100290 kmemleak_warn(x); \
291 kmemleak_disable(); \
292} while (0)
293
294/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100295 * Printing of the objects hex dump to the seq file. The number of lines to be
296 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
297 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
298 * with the object->lock held.
299 */
300static void hex_dump_object(struct seq_file *seq,
301 struct kmemleak_object *object)
302{
303 const u8 *ptr = (const u8 *)object->pointer;
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700304 size_t len;
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100305
306 /* limit the number of lines to HEX_MAX_LINES */
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700307 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100308
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700309 seq_printf(seq, " hex dump (first %zu bytes):\n", len);
310 seq_hex_dump(seq, " ", DUMP_PREFIX_NONE, HEX_ROW_SIZE,
311 HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100312}
313
314/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100315 * Object colors, encoded with count and min_count:
316 * - white - orphan object, not enough references to it (count < min_count)
317 * - gray - not orphan, not marked as false positive (min_count == 0) or
318 * sufficient references to it (count >= min_count)
319 * - black - ignore, it doesn't contain references (e.g. text section)
320 * (min_count == -1). No function defined for this color.
321 * Newly created objects don't have any color assigned (object->count == -1)
322 * before the next memory scan when they become white.
323 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100324static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100325{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700326 return object->count != KMEMLEAK_BLACK &&
327 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100328}
329
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100330static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100331{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700332 return object->min_count != KMEMLEAK_BLACK &&
333 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100334}
335
336/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100337 * Objects are considered unreferenced only if their color is white, they have
338 * not be deleted and have a minimum age to avoid false positives caused by
339 * pointers temporarily stored in CPU registers.
340 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100341static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100342{
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000343 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100344 time_before_eq(object->jiffies + jiffies_min_age,
345 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100346}
347
348/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100349 * Printing of the unreferenced objects information to the seq file. The
350 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100351 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100352static void print_unreferenced(struct seq_file *seq,
353 struct kmemleak_object *object)
354{
355 int i;
Catalin Marinasfefdd332009-10-28 13:33:12 +0000356 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100357
Catalin Marinasbab4a342009-06-26 17:38:26 +0100358 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
359 object->pointer, object->size);
Catalin Marinasfefdd332009-10-28 13:33:12 +0000360 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
361 object->comm, object->pid, object->jiffies,
362 msecs_age / 1000, msecs_age % 1000);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100363 hex_dump_object(seq, object);
Catalin Marinasbab4a342009-06-26 17:38:26 +0100364 seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100365
366 for (i = 0; i < object->trace_len; i++) {
367 void *ptr = (void *)object->trace[i];
Catalin Marinasbab4a342009-06-26 17:38:26 +0100368 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100369 }
370}
371
372/*
373 * Print the kmemleak_object information. This function is used mainly for
374 * debugging special cases when kmemleak operations. It must be called with
375 * the object->lock held.
376 */
377static void dump_object_info(struct kmemleak_object *object)
378{
379 struct stack_trace trace;
380
381 trace.nr_entries = object->trace_len;
382 trace.entries = object->trace;
383
Joe Perchesae281062009-06-23 14:40:26 +0100384 pr_notice("Object 0x%08lx (size %zu):\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700385 object->pointer, object->size);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100386 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
387 object->comm, object->pid, object->jiffies);
388 pr_notice(" min_count = %d\n", object->min_count);
389 pr_notice(" count = %d\n", object->count);
Catalin Marinas189d84e2009-08-27 14:29:15 +0100390 pr_notice(" flags = 0x%lx\n", object->flags);
Jianpeng Maaae0ad72014-06-06 14:38:16 -0700391 pr_notice(" checksum = %u\n", object->checksum);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100392 pr_notice(" backtrace:\n");
393 print_stack_trace(&trace, 4);
394}
395
396/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700397 * Look-up a memory block metadata (kmemleak_object) in the object search
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100398 * tree based on a pointer value. If alias is 0, only values pointing to the
399 * beginning of the memory block are allowed. The kmemleak_lock must be held
400 * when calling this function.
401 */
402static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
403{
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700404 struct rb_node *rb = object_tree_root.rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100405
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700406 while (rb) {
407 struct kmemleak_object *object =
408 rb_entry(rb, struct kmemleak_object, rb_node);
409 if (ptr < object->pointer)
410 rb = object->rb_node.rb_left;
411 else if (object->pointer + object->size <= ptr)
412 rb = object->rb_node.rb_right;
413 else if (object->pointer == ptr || alias)
414 return object;
415 else {
Catalin Marinas5f790202011-09-28 12:17:03 +0100416 kmemleak_warn("Found object by alias at 0x%08lx\n",
417 ptr);
Catalin Marinasa7686a42010-07-19 11:54:16 +0100418 dump_object_info(object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700419 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100420 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700421 }
422 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100423}
424
425/*
426 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
427 * that once an object's use_count reached 0, the RCU freeing was already
428 * registered and the object should no longer be used. This function must be
429 * called under the protection of rcu_read_lock().
430 */
431static int get_object(struct kmemleak_object *object)
432{
433 return atomic_inc_not_zero(&object->use_count);
434}
435
436/*
437 * RCU callback to free a kmemleak_object.
438 */
439static void free_object_rcu(struct rcu_head *rcu)
440{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800441 struct hlist_node *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100442 struct kmemleak_scan_area *area;
443 struct kmemleak_object *object =
444 container_of(rcu, struct kmemleak_object, rcu);
445
446 /*
447 * Once use_count is 0 (guaranteed by put_object), there is no other
448 * code accessing this object, hence no need for locking.
449 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800450 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
451 hlist_del(&area->node);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100452 kmem_cache_free(scan_area_cache, area);
453 }
454 kmem_cache_free(object_cache, object);
455}
456
457/*
458 * Decrement the object use_count. Once the count is 0, free the object using
459 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
460 * delete_object() path, the delayed RCU freeing ensures that there is no
461 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
462 * is also possible.
463 */
464static void put_object(struct kmemleak_object *object)
465{
466 if (!atomic_dec_and_test(&object->use_count))
467 return;
468
469 /* should only get here after delete_object was called */
470 WARN_ON(object->flags & OBJECT_ALLOCATED);
471
472 call_rcu(&object->rcu, free_object_rcu);
473}
474
475/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700476 * Look up an object in the object search tree and increase its use_count.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100477 */
478static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
479{
480 unsigned long flags;
Alexey Klimov9fbed252015-11-05 18:45:57 -0800481 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100482
483 rcu_read_lock();
484 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -0700485 object = lookup_object(ptr, alias);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100486 read_unlock_irqrestore(&kmemleak_lock, flags);
487
488 /* check whether the object is still available */
489 if (object && !get_object(object))
490 object = NULL;
491 rcu_read_unlock();
492
493 return object;
494}
495
496/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700497 * Look up an object in the object search tree and remove it from both
498 * object_tree_root and object_list. The returned object's use_count should be
499 * at least 1, as initially set by create_object().
500 */
501static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
502{
503 unsigned long flags;
504 struct kmemleak_object *object;
505
506 write_lock_irqsave(&kmemleak_lock, flags);
507 object = lookup_object(ptr, alias);
508 if (object) {
509 rb_erase(&object->rb_node, &object_tree_root);
510 list_del_rcu(&object->object_list);
511 }
512 write_unlock_irqrestore(&kmemleak_lock, flags);
513
514 return object;
515}
516
517/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100518 * Save stack trace to the given array of MAX_TRACE size.
519 */
520static int __save_stack_trace(unsigned long *trace)
521{
522 struct stack_trace stack_trace;
523
524 stack_trace.max_entries = MAX_TRACE;
525 stack_trace.nr_entries = 0;
526 stack_trace.entries = trace;
527 stack_trace.skip = 2;
528 save_stack_trace(&stack_trace);
529
530 return stack_trace.nr_entries;
531}
532
533/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100534 * Create the metadata (struct kmemleak_object) corresponding to an allocated
535 * memory block and add it to the object_list and object_tree_root.
536 */
Catalin Marinasfd678962009-08-27 14:29:17 +0100537static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
538 int min_count, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100539{
540 unsigned long flags;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700541 struct kmemleak_object *object, *parent;
542 struct rb_node **link, *rb_parent;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100543
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000544 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100545 if (!object) {
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000546 pr_warning("Cannot allocate a kmemleak_object structure\n");
547 kmemleak_disable();
Catalin Marinasfd678962009-08-27 14:29:17 +0100548 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100549 }
550
551 INIT_LIST_HEAD(&object->object_list);
552 INIT_LIST_HEAD(&object->gray_list);
553 INIT_HLIST_HEAD(&object->area_list);
554 spin_lock_init(&object->lock);
555 atomic_set(&object->use_count, 1);
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000556 object->flags = OBJECT_ALLOCATED;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100557 object->pointer = ptr;
558 object->size = size;
559 object->min_count = min_count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000560 object->count = 0; /* white color initially */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100561 object->jiffies = jiffies;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000562 object->checksum = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100563
564 /* task information */
565 if (in_irq()) {
566 object->pid = 0;
567 strncpy(object->comm, "hardirq", sizeof(object->comm));
568 } else if (in_softirq()) {
569 object->pid = 0;
570 strncpy(object->comm, "softirq", sizeof(object->comm));
571 } else {
572 object->pid = current->pid;
573 /*
574 * There is a small chance of a race with set_task_comm(),
575 * however using get_task_comm() here may cause locking
576 * dependency issues with current->alloc_lock. In the worst
577 * case, the command line is not correct.
578 */
579 strncpy(object->comm, current->comm, sizeof(object->comm));
580 }
581
582 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100583 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100584
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100585 write_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100586
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100587 min_addr = min(min_addr, ptr);
588 max_addr = max(max_addr, ptr + size);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700589 link = &object_tree_root.rb_node;
590 rb_parent = NULL;
591 while (*link) {
592 rb_parent = *link;
593 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
594 if (ptr + size <= parent->pointer)
595 link = &parent->rb_node.rb_left;
596 else if (parent->pointer + parent->size <= ptr)
597 link = &parent->rb_node.rb_right;
598 else {
599 kmemleak_stop("Cannot insert 0x%lx into the object "
600 "search tree (overlaps existing)\n",
601 ptr);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700602 /*
603 * No need for parent->lock here since "parent" cannot
604 * be freed while the kmemleak_lock is held.
605 */
606 dump_object_info(parent);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700607 kmem_cache_free(object_cache, object);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700608 object = NULL;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700609 goto out;
610 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100611 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700612 rb_link_node(&object->rb_node, rb_parent, link);
613 rb_insert_color(&object->rb_node, &object_tree_root);
614
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100615 list_add_tail_rcu(&object->object_list, &object_list);
616out:
617 write_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinasfd678962009-08-27 14:29:17 +0100618 return object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100619}
620
621/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700622 * Mark the object as not allocated and schedule RCU freeing via put_object().
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100623 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100624static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100625{
626 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100627
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100628 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinase781a9a2015-06-24 16:58:29 -0700629 WARN_ON(atomic_read(&object->use_count) < 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100630
631 /*
632 * Locking here also ensures that the corresponding memory block
633 * cannot be freed when it is being scanned.
634 */
635 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100636 object->flags &= ~OBJECT_ALLOCATED;
637 spin_unlock_irqrestore(&object->lock, flags);
638 put_object(object);
639}
640
641/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100642 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
643 * delete it.
644 */
645static void delete_object_full(unsigned long ptr)
646{
647 struct kmemleak_object *object;
648
Catalin Marinase781a9a2015-06-24 16:58:29 -0700649 object = find_and_remove_object(ptr, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100650 if (!object) {
651#ifdef DEBUG
652 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
653 ptr);
654#endif
655 return;
656 }
657 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100658}
659
660/*
661 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
662 * delete it. If the memory block is partially freed, the function may create
663 * additional metadata for the remaining parts of the block.
664 */
665static void delete_object_part(unsigned long ptr, size_t size)
666{
667 struct kmemleak_object *object;
668 unsigned long start, end;
669
Catalin Marinase781a9a2015-06-24 16:58:29 -0700670 object = find_and_remove_object(ptr, 1);
Catalin Marinas53238a62009-07-07 10:33:00 +0100671 if (!object) {
672#ifdef DEBUG
673 kmemleak_warn("Partially freeing unknown object at 0x%08lx "
674 "(size %zu)\n", ptr, size);
675#endif
676 return;
677 }
Catalin Marinas53238a62009-07-07 10:33:00 +0100678
679 /*
680 * Create one or two objects that may result from the memory block
681 * split. Note that partial freeing is only done by free_bootmem() and
682 * this happens before kmemleak_init() is called. The path below is
683 * only executed during early log recording in kmemleak_init(), so
684 * GFP_KERNEL is enough.
685 */
686 start = object->pointer;
687 end = object->pointer + object->size;
688 if (ptr > start)
689 create_object(start, ptr - start, object->min_count,
690 GFP_KERNEL);
691 if (ptr + size < end)
692 create_object(ptr + size, end - ptr - size, object->min_count,
693 GFP_KERNEL);
694
Catalin Marinase781a9a2015-06-24 16:58:29 -0700695 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100696}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700697
698static void __paint_it(struct kmemleak_object *object, int color)
699{
700 object->min_count = color;
701 if (color == KMEMLEAK_BLACK)
702 object->flags |= OBJECT_NO_SCAN;
703}
704
705static void paint_it(struct kmemleak_object *object, int color)
706{
707 unsigned long flags;
708
709 spin_lock_irqsave(&object->lock, flags);
710 __paint_it(object, color);
711 spin_unlock_irqrestore(&object->lock, flags);
712}
713
714static void paint_ptr(unsigned long ptr, int color)
715{
716 struct kmemleak_object *object;
717
718 object = find_and_get_object(ptr, 0);
719 if (!object) {
720 kmemleak_warn("Trying to color unknown object "
721 "at 0x%08lx as %s\n", ptr,
722 (color == KMEMLEAK_GREY) ? "Grey" :
723 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
724 return;
725 }
726 paint_it(object, color);
727 put_object(object);
728}
729
Catalin Marinas53238a62009-07-07 10:33:00 +0100730/*
Holger Hans Peter Freyther145b64b2010-07-22 19:54:13 +0800731 * Mark an object permanently as gray-colored so that it can no longer be
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100732 * reported as a leak. This is used in general to mark a false positive.
733 */
734static void make_gray_object(unsigned long ptr)
735{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700736 paint_ptr(ptr, KMEMLEAK_GREY);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100737}
738
739/*
740 * Mark the object as black-colored so that it is ignored from scans and
741 * reporting.
742 */
743static void make_black_object(unsigned long ptr)
744{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700745 paint_ptr(ptr, KMEMLEAK_BLACK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100746}
747
748/*
749 * Add a scanning area to the object. If at least one such area is added,
750 * kmemleak will only scan these ranges rather than the whole memory block.
751 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000752static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100753{
754 unsigned long flags;
755 struct kmemleak_object *object;
756 struct kmemleak_scan_area *area;
757
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000758 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100759 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100760 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
761 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100762 return;
763 }
764
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000765 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100766 if (!area) {
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000767 pr_warning("Cannot allocate a scan area\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100768 goto out;
769 }
770
771 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas7f88f882013-11-12 15:07:45 -0800772 if (size == SIZE_MAX) {
773 size = object->pointer + object->size - ptr;
774 } else if (ptr + size > object->pointer + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100775 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100776 dump_object_info(object);
777 kmem_cache_free(scan_area_cache, area);
778 goto out_unlock;
779 }
780
781 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000782 area->start = ptr;
783 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100784
785 hlist_add_head(&area->node, &object->area_list);
786out_unlock:
787 spin_unlock_irqrestore(&object->lock, flags);
788out:
789 put_object(object);
790}
791
792/*
793 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
794 * pointer. Such object will not be scanned by kmemleak but references to it
795 * are searched.
796 */
797static void object_no_scan(unsigned long ptr)
798{
799 unsigned long flags;
800 struct kmemleak_object *object;
801
802 object = find_and_get_object(ptr, 0);
803 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100804 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100805 return;
806 }
807
808 spin_lock_irqsave(&object->lock, flags);
809 object->flags |= OBJECT_NO_SCAN;
810 spin_unlock_irqrestore(&object->lock, flags);
811 put_object(object);
812}
813
814/*
815 * Log an early kmemleak_* call to the early_log buffer. These calls will be
816 * processed later once kmemleak is fully initialized.
817 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100818static void __init log_early(int op_type, const void *ptr, size_t size,
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000819 int min_count)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100820{
821 unsigned long flags;
822 struct early_log *log;
823
Li Zefan8910ae82014-04-03 14:46:29 -0700824 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +0100825 /* kmemleak stopped recording, just count the requests */
826 crt_early_log++;
827 return;
828 }
829
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100830 if (crt_early_log >= ARRAY_SIZE(early_log)) {
Wang Kai21cd3a62015-09-08 15:03:41 -0700831 crt_early_log++;
Catalin Marinasa9d90582009-06-25 10:16:11 +0100832 kmemleak_disable();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100833 return;
834 }
835
836 /*
837 * There is no need for locking since the kernel is still in UP mode
838 * at this stage. Disabling the IRQs is enough.
839 */
840 local_irq_save(flags);
841 log = &early_log[crt_early_log];
842 log->op_type = op_type;
843 log->ptr = ptr;
844 log->size = size;
845 log->min_count = min_count;
Catalin Marinas5f790202011-09-28 12:17:03 +0100846 log->trace_len = __save_stack_trace(log->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100847 crt_early_log++;
848 local_irq_restore(flags);
849}
850
851/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100852 * Log an early allocated block and populate the stack trace.
853 */
854static void early_alloc(struct early_log *log)
855{
856 struct kmemleak_object *object;
857 unsigned long flags;
858 int i;
859
Li Zefan8910ae82014-04-03 14:46:29 -0700860 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
Catalin Marinasfd678962009-08-27 14:29:17 +0100861 return;
862
863 /*
864 * RCU locking needed to ensure object is not freed via put_object().
865 */
866 rcu_read_lock();
867 object = create_object((unsigned long)log->ptr, log->size,
Tetsuo Handac1bcd6b2009-10-09 10:39:24 +0100868 log->min_count, GFP_ATOMIC);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100869 if (!object)
870 goto out;
Catalin Marinasfd678962009-08-27 14:29:17 +0100871 spin_lock_irqsave(&object->lock, flags);
872 for (i = 0; i < log->trace_len; i++)
873 object->trace[i] = log->trace[i];
874 object->trace_len = log->trace_len;
875 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100876out:
Catalin Marinasfd678962009-08-27 14:29:17 +0100877 rcu_read_unlock();
878}
879
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100880/*
881 * Log an early allocated block and populate the stack trace.
882 */
883static void early_alloc_percpu(struct early_log *log)
884{
885 unsigned int cpu;
886 const void __percpu *ptr = log->ptr;
887
888 for_each_possible_cpu(cpu) {
889 log->ptr = per_cpu_ptr(ptr, cpu);
890 early_alloc(log);
891 }
892}
893
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100894/**
895 * kmemleak_alloc - register a newly allocated object
896 * @ptr: pointer to beginning of the object
897 * @size: size of the object
898 * @min_count: minimum number of references to this object. If during memory
899 * scanning a number of references less than @min_count is found,
900 * the object is reported as a memory leak. If @min_count is 0,
901 * the object is never reported as a leak. If @min_count is -1,
902 * the object is ignored (not scanned and not reported as a leak)
903 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
904 *
905 * This function is called from the kernel allocators when a new object
906 * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100907 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100908void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
909 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100910{
911 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
912
Li Zefan8910ae82014-04-03 14:46:29 -0700913 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100914 create_object((unsigned long)ptr, size, min_count, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700915 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000916 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100917}
918EXPORT_SYMBOL_GPL(kmemleak_alloc);
919
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100920/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100921 * kmemleak_alloc_percpu - register a newly allocated __percpu object
922 * @ptr: __percpu pointer to beginning of the object
923 * @size: size of the object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700924 * @gfp: flags used for kmemleak internal memory allocations
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100925 *
926 * This function is called from the kernel percpu allocator when a new object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700927 * (memory block) is allocated (alloc_percpu).
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100928 */
Larry Finger8a8c35f2015-06-24 16:58:51 -0700929void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
930 gfp_t gfp)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100931{
932 unsigned int cpu;
933
934 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
935
936 /*
937 * Percpu allocations are only scanned and not reported as leaks
938 * (min_count is set to 0).
939 */
Li Zefan8910ae82014-04-03 14:46:29 -0700940 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100941 for_each_possible_cpu(cpu)
942 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
Larry Finger8a8c35f2015-06-24 16:58:51 -0700943 size, 0, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700944 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100945 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
946}
947EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
948
949/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100950 * kmemleak_free - unregister a previously registered object
951 * @ptr: pointer to beginning of the object
952 *
953 * This function is called from the kernel allocators when an object (memory
954 * block) is freed (kmem_cache_free, kfree, vfree etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100955 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100956void __ref kmemleak_free(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100957{
958 pr_debug("%s(0x%p)\n", __func__, ptr);
959
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700960 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +0100961 delete_object_full((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -0700962 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000963 log_early(KMEMLEAK_FREE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100964}
965EXPORT_SYMBOL_GPL(kmemleak_free);
966
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100967/**
968 * kmemleak_free_part - partially unregister a previously registered object
969 * @ptr: pointer to the beginning or inside the object. This also
970 * represents the start of the range to be freed
971 * @size: size to be unregistered
972 *
973 * This function is called when only a part of a memory block is freed
974 * (usually from the bootmem allocator).
Catalin Marinas53238a62009-07-07 10:33:00 +0100975 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100976void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +0100977{
978 pr_debug("%s(0x%p)\n", __func__, ptr);
979
Li Zefan8910ae82014-04-03 14:46:29 -0700980 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +0100981 delete_object_part((unsigned long)ptr, size);
Li Zefan8910ae82014-04-03 14:46:29 -0700982 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000983 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100984}
985EXPORT_SYMBOL_GPL(kmemleak_free_part);
986
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100987/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100988 * kmemleak_free_percpu - unregister a previously registered __percpu object
989 * @ptr: __percpu pointer to beginning of the object
990 *
991 * This function is called from the kernel percpu allocator when an object
992 * (memory block) is freed (free_percpu).
993 */
994void __ref kmemleak_free_percpu(const void __percpu *ptr)
995{
996 unsigned int cpu;
997
998 pr_debug("%s(0x%p)\n", __func__, ptr);
999
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001000 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001001 for_each_possible_cpu(cpu)
1002 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1003 cpu));
Li Zefan8910ae82014-04-03 14:46:29 -07001004 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001005 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1006}
1007EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1008
1009/**
Catalin Marinasffe2c742014-06-06 14:38:17 -07001010 * kmemleak_update_trace - update object allocation stack trace
1011 * @ptr: pointer to beginning of the object
1012 *
1013 * Override the object allocation stack trace for cases where the actual
1014 * allocation place is not always useful.
1015 */
1016void __ref kmemleak_update_trace(const void *ptr)
1017{
1018 struct kmemleak_object *object;
1019 unsigned long flags;
1020
1021 pr_debug("%s(0x%p)\n", __func__, ptr);
1022
1023 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1024 return;
1025
1026 object = find_and_get_object((unsigned long)ptr, 1);
1027 if (!object) {
1028#ifdef DEBUG
1029 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1030 ptr);
1031#endif
1032 return;
1033 }
1034
1035 spin_lock_irqsave(&object->lock, flags);
1036 object->trace_len = __save_stack_trace(object->trace);
1037 spin_unlock_irqrestore(&object->lock, flags);
1038
1039 put_object(object);
1040}
1041EXPORT_SYMBOL(kmemleak_update_trace);
1042
1043/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001044 * kmemleak_not_leak - mark an allocated object as false positive
1045 * @ptr: pointer to beginning of the object
1046 *
1047 * Calling this function on an object will cause the memory block to no longer
1048 * be reported as leak and always be scanned.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001049 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001050void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001051{
1052 pr_debug("%s(0x%p)\n", __func__, ptr);
1053
Li Zefan8910ae82014-04-03 14:46:29 -07001054 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001055 make_gray_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001056 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001057 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001058}
1059EXPORT_SYMBOL(kmemleak_not_leak);
1060
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001061/**
1062 * kmemleak_ignore - ignore an allocated object
1063 * @ptr: pointer to beginning of the object
1064 *
1065 * Calling this function on an object will cause the memory block to be
1066 * ignored (not scanned and not reported as a leak). This is usually done when
1067 * it is known that the corresponding block is not a leak and does not contain
1068 * any references to other allocated memory blocks.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001069 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001070void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001071{
1072 pr_debug("%s(0x%p)\n", __func__, ptr);
1073
Li Zefan8910ae82014-04-03 14:46:29 -07001074 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001075 make_black_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001076 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001077 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001078}
1079EXPORT_SYMBOL(kmemleak_ignore);
1080
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001081/**
1082 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1083 * @ptr: pointer to beginning or inside the object. This also
1084 * represents the start of the scan area
1085 * @size: size of the scan area
1086 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1087 *
1088 * This function is used when it is known that only certain parts of an object
1089 * contain references to other objects. Kmemleak will only scan these areas
1090 * reducing the number false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001091 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001092void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001093{
1094 pr_debug("%s(0x%p)\n", __func__, ptr);
1095
Li Zefan8910ae82014-04-03 14:46:29 -07001096 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001097 add_scan_area((unsigned long)ptr, size, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -07001098 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001099 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001100}
1101EXPORT_SYMBOL(kmemleak_scan_area);
1102
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001103/**
1104 * kmemleak_no_scan - do not scan an allocated object
1105 * @ptr: pointer to beginning of the object
1106 *
1107 * This function notifies kmemleak not to scan the given memory block. Useful
1108 * in situations where it is known that the given object does not contain any
1109 * references to other objects. Kmemleak will not scan such objects reducing
1110 * the number of false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001111 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001112void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001113{
1114 pr_debug("%s(0x%p)\n", __func__, ptr);
1115
Li Zefan8910ae82014-04-03 14:46:29 -07001116 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001117 object_no_scan((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001118 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001119 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001120}
1121EXPORT_SYMBOL(kmemleak_no_scan);
1122
1123/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001124 * Update an object's checksum and return true if it was modified.
1125 */
1126static bool update_checksum(struct kmemleak_object *object)
1127{
1128 u32 old_csum = object->checksum;
1129
1130 if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
1131 return false;
1132
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001133 kasan_disable_current();
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001134 object->checksum = crc32(0, (void *)object->pointer, object->size);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001135 kasan_enable_current();
1136
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001137 return object->checksum != old_csum;
1138}
1139
1140/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001141 * Memory scanning is a long process and it needs to be interruptable. This
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001142 * function checks whether such interrupt condition occurred.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001143 */
1144static int scan_should_stop(void)
1145{
Li Zefan8910ae82014-04-03 14:46:29 -07001146 if (!kmemleak_enabled)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001147 return 1;
1148
1149 /*
1150 * This function may be called from either process or kthread context,
1151 * hence the need to check for both stop conditions.
1152 */
1153 if (current->mm)
1154 return signal_pending(current);
1155 else
1156 return kthread_should_stop();
1157
1158 return 0;
1159}
1160
1161/*
1162 * Scan a memory block (exclusive range) for valid pointers and add those
1163 * found to the gray list.
1164 */
1165static void scan_block(void *_start, void *_end,
Catalin Marinas93ada572015-06-24 16:58:37 -07001166 struct kmemleak_object *scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001167{
1168 unsigned long *ptr;
1169 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1170 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
Catalin Marinas93ada572015-06-24 16:58:37 -07001171 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001172
Catalin Marinas93ada572015-06-24 16:58:37 -07001173 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001174 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001175 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +01001176 unsigned long pointer;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001177
1178 if (scan_should_stop())
1179 break;
1180
Pekka Enberg8e019362009-08-27 14:50:00 +01001181 /* don't scan uninitialized memory */
1182 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
1183 BYTES_PER_POINTER))
1184 continue;
1185
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001186 kasan_disable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001187 pointer = *ptr;
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001188 kasan_enable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001189
Catalin Marinas93ada572015-06-24 16:58:37 -07001190 if (pointer < min_addr || pointer >= max_addr)
1191 continue;
1192
1193 /*
1194 * No need for get_object() here since we hold kmemleak_lock.
1195 * object->use_count cannot be dropped to 0 while the object
1196 * is still present in object_tree_root and object_list
1197 * (with updates protected by kmemleak_lock).
1198 */
1199 object = lookup_object(pointer, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001200 if (!object)
1201 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001202 if (object == scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001203 /* self referenced, ignore */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001204 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001205
1206 /*
1207 * Avoid the lockdep recursive warning on object->lock being
1208 * previously acquired in scan_object(). These locks are
1209 * enclosed by scan_mutex.
1210 */
Catalin Marinas93ada572015-06-24 16:58:37 -07001211 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001212 if (!color_white(object)) {
1213 /* non-orphan, ignored or new */
Catalin Marinas93ada572015-06-24 16:58:37 -07001214 spin_unlock(&object->lock);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001215 continue;
1216 }
1217
1218 /*
1219 * Increase the object's reference count (number of pointers
1220 * to the memory block). If this count reaches the required
1221 * minimum, the object's color will become gray and it will be
1222 * added to the gray_list.
1223 */
1224 object->count++;
Catalin Marinas0587da42009-10-28 13:33:11 +00001225 if (color_gray(object)) {
Catalin Marinas93ada572015-06-24 16:58:37 -07001226 /* put_object() called when removing from gray_list */
1227 WARN_ON(!get_object(object));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001228 list_add_tail(&object->gray_list, &gray_list);
Catalin Marinas0587da42009-10-28 13:33:11 +00001229 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001230 spin_unlock(&object->lock);
1231 }
1232 read_unlock_irqrestore(&kmemleak_lock, flags);
1233}
Catalin Marinas0587da42009-10-28 13:33:11 +00001234
Catalin Marinas93ada572015-06-24 16:58:37 -07001235/*
1236 * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1237 */
1238static void scan_large_block(void *start, void *end)
1239{
1240 void *next;
1241
1242 while (start < end) {
1243 next = min(start + MAX_SCAN_SIZE, end);
1244 scan_block(start, next, NULL);
1245 start = next;
1246 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001247 }
1248}
1249
1250/*
1251 * Scan a memory block corresponding to a kmemleak_object. A condition is
1252 * that object->use_count >= 1.
1253 */
1254static void scan_object(struct kmemleak_object *object)
1255{
1256 struct kmemleak_scan_area *area;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001257 unsigned long flags;
1258
1259 /*
Uwe Kleine-König21ae2952009-10-07 15:21:09 +02001260 * Once the object->lock is acquired, the corresponding memory block
1261 * cannot be freed (the same lock is acquired in delete_object).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001262 */
1263 spin_lock_irqsave(&object->lock, flags);
1264 if (object->flags & OBJECT_NO_SCAN)
1265 goto out;
1266 if (!(object->flags & OBJECT_ALLOCATED))
1267 /* already freed object */
1268 goto out;
Catalin Marinasaf986032009-08-27 14:29:12 +01001269 if (hlist_empty(&object->area_list)) {
1270 void *start = (void *)object->pointer;
1271 void *end = (void *)(object->pointer + object->size);
Catalin Marinas93ada572015-06-24 16:58:37 -07001272 void *next;
Catalin Marinasaf986032009-08-27 14:29:12 +01001273
Catalin Marinas93ada572015-06-24 16:58:37 -07001274 do {
1275 next = min(start + MAX_SCAN_SIZE, end);
1276 scan_block(start, next, object);
1277
1278 start = next;
1279 if (start >= end)
1280 break;
Catalin Marinasaf986032009-08-27 14:29:12 +01001281
1282 spin_unlock_irqrestore(&object->lock, flags);
1283 cond_resched();
1284 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -07001285 } while (object->flags & OBJECT_ALLOCATED);
Catalin Marinasaf986032009-08-27 14:29:12 +01001286 } else
Sasha Levinb67bfe02013-02-27 17:06:00 -08001287 hlist_for_each_entry(area, &object->area_list, node)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001288 scan_block((void *)area->start,
1289 (void *)(area->start + area->size),
Catalin Marinas93ada572015-06-24 16:58:37 -07001290 object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001291out:
1292 spin_unlock_irqrestore(&object->lock, flags);
1293}
1294
1295/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001296 * Scan the objects already referenced (gray objects). More objects will be
1297 * referenced and, if there are no memory leaks, all the objects are scanned.
1298 */
1299static void scan_gray_list(void)
1300{
1301 struct kmemleak_object *object, *tmp;
1302
1303 /*
1304 * The list traversal is safe for both tail additions and removals
1305 * from inside the loop. The kmemleak objects cannot be freed from
1306 * outside the loop because their use_count was incremented.
1307 */
1308 object = list_entry(gray_list.next, typeof(*object), gray_list);
1309 while (&object->gray_list != &gray_list) {
1310 cond_resched();
1311
1312 /* may add new objects to the list */
1313 if (!scan_should_stop())
1314 scan_object(object);
1315
1316 tmp = list_entry(object->gray_list.next, typeof(*object),
1317 gray_list);
1318
1319 /* remove the object from the list and release it */
1320 list_del(&object->gray_list);
1321 put_object(object);
1322
1323 object = tmp;
1324 }
1325 WARN_ON(!list_empty(&gray_list));
1326}
1327
1328/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001329 * Scan data sections and all the referenced memory blocks allocated via the
1330 * kernel's standard allocators. This function must be called with the
1331 * scan_mutex held.
1332 */
1333static void kmemleak_scan(void)
1334{
1335 unsigned long flags;
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001336 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001337 int i;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001338 int new_leaks = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001339
Catalin Marinasacf49682009-06-26 17:38:29 +01001340 jiffies_last_scan = jiffies;
1341
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001342 /* prepare the kmemleak_object's */
1343 rcu_read_lock();
1344 list_for_each_entry_rcu(object, &object_list, object_list) {
1345 spin_lock_irqsave(&object->lock, flags);
1346#ifdef DEBUG
1347 /*
1348 * With a few exceptions there should be a maximum of
1349 * 1 reference to any object at this point.
1350 */
1351 if (atomic_read(&object->use_count) > 1) {
Joe Perchesae281062009-06-23 14:40:26 +01001352 pr_debug("object->use_count = %d\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001353 atomic_read(&object->use_count));
1354 dump_object_info(object);
1355 }
1356#endif
1357 /* reset the reference count (whiten the object) */
1358 object->count = 0;
1359 if (color_gray(object) && get_object(object))
1360 list_add_tail(&object->gray_list, &gray_list);
1361
1362 spin_unlock_irqrestore(&object->lock, flags);
1363 }
1364 rcu_read_unlock();
1365
1366 /* data/bss scanning */
Catalin Marinas93ada572015-06-24 16:58:37 -07001367 scan_large_block(_sdata, _edata);
1368 scan_large_block(__bss_start, __bss_stop);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001369
1370#ifdef CONFIG_SMP
1371 /* per-cpu sections scanning */
1372 for_each_possible_cpu(i)
Catalin Marinas93ada572015-06-24 16:58:37 -07001373 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1374 __per_cpu_end + per_cpu_offset(i));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001375#endif
1376
1377 /*
Laura Abbott029aeff2011-11-15 23:49:09 +00001378 * Struct page scanning for each node.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001379 */
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001380 get_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001381 for_each_online_node(i) {
Cody P Schafer108bcc92013-02-22 16:35:23 -08001382 unsigned long start_pfn = node_start_pfn(i);
1383 unsigned long end_pfn = node_end_pfn(i);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001384 unsigned long pfn;
1385
1386 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1387 struct page *page;
1388
1389 if (!pfn_valid(pfn))
1390 continue;
1391 page = pfn_to_page(pfn);
1392 /* only scan if page is in use */
1393 if (page_count(page) == 0)
1394 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001395 scan_block(page, page + 1, NULL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001396 }
1397 }
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001398 put_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001399
1400 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001401 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001402 */
1403 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001404 struct task_struct *p, *g;
1405
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001406 read_lock(&tasklist_lock);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001407 do_each_thread(g, p) {
1408 scan_block(task_stack_page(p), task_stack_page(p) +
Catalin Marinas93ada572015-06-24 16:58:37 -07001409 THREAD_SIZE, NULL);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001410 } while_each_thread(g, p);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001411 read_unlock(&tasklist_lock);
1412 }
1413
1414 /*
1415 * Scan the objects already referenced from the sections scanned
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001416 * above.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001417 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001418 scan_gray_list();
Catalin Marinas25873622009-07-07 10:32:58 +01001419
1420 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001421 * Check for new or unreferenced objects modified since the previous
1422 * scan and color them gray until the next scan.
Catalin Marinas25873622009-07-07 10:32:58 +01001423 */
1424 rcu_read_lock();
1425 list_for_each_entry_rcu(object, &object_list, object_list) {
1426 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001427 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1428 && update_checksum(object) && get_object(object)) {
1429 /* color it gray temporarily */
1430 object->count = object->min_count;
Catalin Marinas25873622009-07-07 10:32:58 +01001431 list_add_tail(&object->gray_list, &gray_list);
1432 }
1433 spin_unlock_irqrestore(&object->lock, flags);
1434 }
1435 rcu_read_unlock();
1436
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001437 /*
1438 * Re-scan the gray list for modified unreferenced objects.
1439 */
1440 scan_gray_list();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001441
1442 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001443 * If scanning was stopped do not report any new unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001444 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001445 if (scan_should_stop())
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001446 return;
1447
1448 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001449 * Scanning result reporting.
1450 */
1451 rcu_read_lock();
1452 list_for_each_entry_rcu(object, &object_list, object_list) {
1453 spin_lock_irqsave(&object->lock, flags);
1454 if (unreferenced_object(object) &&
1455 !(object->flags & OBJECT_REPORTED)) {
1456 object->flags |= OBJECT_REPORTED;
1457 new_leaks++;
1458 }
1459 spin_unlock_irqrestore(&object->lock, flags);
1460 }
1461 rcu_read_unlock();
1462
Li Zefandc9b3f42014-04-03 14:46:26 -07001463 if (new_leaks) {
1464 kmemleak_found_leaks = true;
1465
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001466 pr_info("%d new suspected memory leaks (see "
1467 "/sys/kernel/debug/kmemleak)\n", new_leaks);
Li Zefandc9b3f42014-04-03 14:46:26 -07001468 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001469
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001470}
1471
1472/*
1473 * Thread function performing automatic memory scanning. Unreferenced objects
1474 * at the end of a memory scan are reported but only the first time.
1475 */
1476static int kmemleak_scan_thread(void *arg)
1477{
1478 static int first_run = 1;
1479
Joe Perchesae281062009-06-23 14:40:26 +01001480 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001481 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001482
1483 /*
1484 * Wait before the first scan to allow the system to fully initialize.
1485 */
1486 if (first_run) {
1487 first_run = 0;
1488 ssleep(SECS_FIRST_SCAN);
1489 }
1490
1491 while (!kthread_should_stop()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001492 signed long timeout = jiffies_scan_wait;
1493
1494 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001495 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001496 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001497
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001498 /* wait before the next scan */
1499 while (timeout && !kthread_should_stop())
1500 timeout = schedule_timeout_interruptible(timeout);
1501 }
1502
Joe Perchesae281062009-06-23 14:40:26 +01001503 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001504
1505 return 0;
1506}
1507
1508/*
1509 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001510 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001511 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001512static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001513{
1514 if (scan_thread)
1515 return;
1516 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1517 if (IS_ERR(scan_thread)) {
Joe Perchesae281062009-06-23 14:40:26 +01001518 pr_warning("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001519 scan_thread = NULL;
1520 }
1521}
1522
1523/*
1524 * Stop the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001525 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001526 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001527static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001528{
1529 if (scan_thread) {
1530 kthread_stop(scan_thread);
1531 scan_thread = NULL;
1532 }
1533}
1534
1535/*
1536 * Iterate over the object_list and return the first valid object at or after
1537 * the required position with its use_count incremented. The function triggers
1538 * a memory scanning when the pos argument points to the first position.
1539 */
1540static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1541{
1542 struct kmemleak_object *object;
1543 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001544 int err;
1545
1546 err = mutex_lock_interruptible(&scan_mutex);
1547 if (err < 0)
1548 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001549
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001550 rcu_read_lock();
1551 list_for_each_entry_rcu(object, &object_list, object_list) {
1552 if (n-- > 0)
1553 continue;
1554 if (get_object(object))
1555 goto out;
1556 }
1557 object = NULL;
1558out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001559 return object;
1560}
1561
1562/*
1563 * Return the next object in the object_list. The function decrements the
1564 * use_count of the previous object and increases that of the next one.
1565 */
1566static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1567{
1568 struct kmemleak_object *prev_obj = v;
1569 struct kmemleak_object *next_obj = NULL;
Michael Wang58fac092012-08-17 12:33:34 +08001570 struct kmemleak_object *obj = prev_obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001571
1572 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001573
Michael Wang58fac092012-08-17 12:33:34 +08001574 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001575 if (get_object(obj)) {
1576 next_obj = obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001577 break;
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001578 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001579 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001580
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001581 put_object(prev_obj);
1582 return next_obj;
1583}
1584
1585/*
1586 * Decrement the use_count of the last object required, if any.
1587 */
1588static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1589{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001590 if (!IS_ERR(v)) {
1591 /*
1592 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1593 * waiting was interrupted, so only release it if !IS_ERR.
1594 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001595 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001596 mutex_unlock(&scan_mutex);
1597 if (v)
1598 put_object(v);
1599 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001600}
1601
1602/*
1603 * Print the information for an unreferenced object to the seq file.
1604 */
1605static int kmemleak_seq_show(struct seq_file *seq, void *v)
1606{
1607 struct kmemleak_object *object = v;
1608 unsigned long flags;
1609
1610 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001611 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001612 print_unreferenced(seq, object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001613 spin_unlock_irqrestore(&object->lock, flags);
1614 return 0;
1615}
1616
1617static const struct seq_operations kmemleak_seq_ops = {
1618 .start = kmemleak_seq_start,
1619 .next = kmemleak_seq_next,
1620 .stop = kmemleak_seq_stop,
1621 .show = kmemleak_seq_show,
1622};
1623
1624static int kmemleak_open(struct inode *inode, struct file *file)
1625{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001626 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001627}
1628
Catalin Marinas189d84e2009-08-27 14:29:15 +01001629static int dump_str_object_info(const char *str)
1630{
1631 unsigned long flags;
1632 struct kmemleak_object *object;
1633 unsigned long addr;
1634
Abhijit Pawardc053732012-12-18 14:23:27 -08001635 if (kstrtoul(str, 0, &addr))
1636 return -EINVAL;
Catalin Marinas189d84e2009-08-27 14:29:15 +01001637 object = find_and_get_object(addr, 0);
1638 if (!object) {
1639 pr_info("Unknown object at 0x%08lx\n", addr);
1640 return -EINVAL;
1641 }
1642
1643 spin_lock_irqsave(&object->lock, flags);
1644 dump_object_info(object);
1645 spin_unlock_irqrestore(&object->lock, flags);
1646
1647 put_object(object);
1648 return 0;
1649}
1650
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001651/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001652 * We use grey instead of black to ensure we can do future scans on the same
1653 * objects. If we did not do future scans these black objects could
1654 * potentially contain references to newly allocated objects in the future and
1655 * we'd end up with false positives.
1656 */
1657static void kmemleak_clear(void)
1658{
1659 struct kmemleak_object *object;
1660 unsigned long flags;
1661
1662 rcu_read_lock();
1663 list_for_each_entry_rcu(object, &object_list, object_list) {
1664 spin_lock_irqsave(&object->lock, flags);
1665 if ((object->flags & OBJECT_REPORTED) &&
1666 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001667 __paint_it(object, KMEMLEAK_GREY);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001668 spin_unlock_irqrestore(&object->lock, flags);
1669 }
1670 rcu_read_unlock();
Li Zefandc9b3f42014-04-03 14:46:26 -07001671
1672 kmemleak_found_leaks = false;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001673}
1674
Li Zefanc89da702014-04-03 14:46:27 -07001675static void __kmemleak_do_cleanup(void);
1676
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001677/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001678 * File write operation to configure kmemleak at run-time. The following
1679 * commands can be written to the /sys/kernel/debug/kmemleak file:
1680 * off - disable kmemleak (irreversible)
1681 * stack=on - enable the task stacks scanning
1682 * stack=off - disable the tasks stacks scanning
1683 * scan=on - start the automatic memory scanning thread
1684 * scan=off - stop the automatic memory scanning thread
1685 * scan=... - set the automatic memory scanning period in seconds (0 to
1686 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001687 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001688 * clear - mark all current reported unreferenced kmemleak objects as
Li Zefanc89da702014-04-03 14:46:27 -07001689 * grey to ignore printing them, or free all kmemleak objects
1690 * if kmemleak has been disabled.
Catalin Marinas189d84e2009-08-27 14:29:15 +01001691 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001692 */
1693static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1694 size_t size, loff_t *ppos)
1695{
1696 char buf[64];
1697 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001698 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001699
1700 buf_size = min(size, (sizeof(buf) - 1));
1701 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1702 return -EFAULT;
1703 buf[buf_size] = 0;
1704
Catalin Marinasb87324d2009-07-07 10:32:58 +01001705 ret = mutex_lock_interruptible(&scan_mutex);
1706 if (ret < 0)
1707 return ret;
1708
Li Zefanc89da702014-04-03 14:46:27 -07001709 if (strncmp(buf, "clear", 5) == 0) {
Li Zefan8910ae82014-04-03 14:46:29 -07001710 if (kmemleak_enabled)
Li Zefanc89da702014-04-03 14:46:27 -07001711 kmemleak_clear();
1712 else
1713 __kmemleak_do_cleanup();
1714 goto out;
1715 }
1716
Li Zefan8910ae82014-04-03 14:46:29 -07001717 if (!kmemleak_enabled) {
Li Zefanc89da702014-04-03 14:46:27 -07001718 ret = -EBUSY;
1719 goto out;
1720 }
1721
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001722 if (strncmp(buf, "off", 3) == 0)
1723 kmemleak_disable();
1724 else if (strncmp(buf, "stack=on", 8) == 0)
1725 kmemleak_stack_scan = 1;
1726 else if (strncmp(buf, "stack=off", 9) == 0)
1727 kmemleak_stack_scan = 0;
1728 else if (strncmp(buf, "scan=on", 7) == 0)
1729 start_scan_thread();
1730 else if (strncmp(buf, "scan=off", 8) == 0)
1731 stop_scan_thread();
1732 else if (strncmp(buf, "scan=", 5) == 0) {
1733 unsigned long secs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001734
Jingoo Han3dbb95f2013-09-11 14:20:25 -07001735 ret = kstrtoul(buf + 5, 0, &secs);
Catalin Marinasb87324d2009-07-07 10:32:58 +01001736 if (ret < 0)
1737 goto out;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001738 stop_scan_thread();
1739 if (secs) {
1740 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1741 start_scan_thread();
1742 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001743 } else if (strncmp(buf, "scan", 4) == 0)
1744 kmemleak_scan();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001745 else if (strncmp(buf, "dump=", 5) == 0)
1746 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001747 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001748 ret = -EINVAL;
1749
1750out:
1751 mutex_unlock(&scan_mutex);
1752 if (ret < 0)
1753 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001754
1755 /* ignore the rest of the buffer, only one command at a time */
1756 *ppos += size;
1757 return size;
1758}
1759
1760static const struct file_operations kmemleak_fops = {
1761 .owner = THIS_MODULE,
1762 .open = kmemleak_open,
1763 .read = seq_read,
1764 .write = kmemleak_write,
1765 .llseek = seq_lseek,
Li Zefan5f3bf192014-04-03 14:46:28 -07001766 .release = seq_release,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001767};
1768
Li Zefanc89da702014-04-03 14:46:27 -07001769static void __kmemleak_do_cleanup(void)
1770{
1771 struct kmemleak_object *object;
1772
1773 rcu_read_lock();
1774 list_for_each_entry_rcu(object, &object_list, object_list)
1775 delete_object_full(object->pointer);
1776 rcu_read_unlock();
1777}
1778
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001779/*
Catalin Marinas74341702011-09-29 11:50:07 +01001780 * Stop the memory scanning thread and free the kmemleak internal objects if
1781 * no previous scan thread (otherwise, kmemleak may still have some useful
1782 * information on memory leaks).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001783 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001784static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001785{
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001786 stop_scan_thread();
1787
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001788 /*
1789 * Once the scan thread has stopped, it is safe to no longer track
1790 * object freeing. Ordering of the scan thread stopping and the memory
1791 * accesses below is guaranteed by the kthread_stop() function.
1792 */
1793 kmemleak_free_enabled = 0;
1794
Li Zefanc89da702014-04-03 14:46:27 -07001795 if (!kmemleak_found_leaks)
1796 __kmemleak_do_cleanup();
1797 else
1798 pr_info("Kmemleak disabled without freeing internal data. "
1799 "Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\"\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001800}
1801
Catalin Marinas179a8102009-09-07 10:14:42 +01001802static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001803
1804/*
1805 * Disable kmemleak. No memory allocation/freeing will be traced once this
1806 * function is called. Disabling kmemleak is an irreversible operation.
1807 */
1808static void kmemleak_disable(void)
1809{
1810 /* atomically check whether it was already invoked */
Li Zefan8910ae82014-04-03 14:46:29 -07001811 if (cmpxchg(&kmemleak_error, 0, 1))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001812 return;
1813
1814 /* stop any memory operation tracing */
Li Zefan8910ae82014-04-03 14:46:29 -07001815 kmemleak_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001816
1817 /* check whether it is too early for a kernel thread */
Li Zefan8910ae82014-04-03 14:46:29 -07001818 if (kmemleak_initialized)
Catalin Marinas179a8102009-09-07 10:14:42 +01001819 schedule_work(&cleanup_work);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001820 else
1821 kmemleak_free_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001822
1823 pr_info("Kernel memory leak detector disabled\n");
1824}
1825
1826/*
1827 * Allow boot-time kmemleak disabling (enabled by default).
1828 */
1829static int kmemleak_boot_config(char *str)
1830{
1831 if (!str)
1832 return -EINVAL;
1833 if (strcmp(str, "off") == 0)
1834 kmemleak_disable();
Jason Baronab0155a2010-07-19 11:54:17 +01001835 else if (strcmp(str, "on") == 0)
1836 kmemleak_skip_disable = 1;
1837 else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001838 return -EINVAL;
1839 return 0;
1840}
1841early_param("kmemleak", kmemleak_boot_config);
1842
Catalin Marinas5f790202011-09-28 12:17:03 +01001843static void __init print_log_trace(struct early_log *log)
1844{
1845 struct stack_trace trace;
1846
1847 trace.nr_entries = log->trace_len;
1848 trace.entries = log->trace;
1849
1850 pr_notice("Early log backtrace:\n");
1851 print_stack_trace(&trace, 2);
1852}
1853
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001854/*
Catalin Marinas20301172009-06-17 18:29:04 +01001855 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001856 */
1857void __init kmemleak_init(void)
1858{
1859 int i;
1860 unsigned long flags;
1861
Jason Baronab0155a2010-07-19 11:54:17 +01001862#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
1863 if (!kmemleak_skip_disable) {
Catalin Marinas3551a922014-05-09 15:36:59 -07001864 kmemleak_early_log = 0;
Jason Baronab0155a2010-07-19 11:54:17 +01001865 kmemleak_disable();
1866 return;
1867 }
1868#endif
1869
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001870 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
1871 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
1872
1873 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
1874 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001875
Wang Kai21cd3a62015-09-08 15:03:41 -07001876 if (crt_early_log > ARRAY_SIZE(early_log))
Catalin Marinasb6693002011-09-28 17:22:56 +01001877 pr_warning("Early log buffer exceeded (%d), please increase "
1878 "DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n", crt_early_log);
1879
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001880 /* the kernel is still in UP mode, so disabling the IRQs is enough */
1881 local_irq_save(flags);
Catalin Marinas3551a922014-05-09 15:36:59 -07001882 kmemleak_early_log = 0;
Li Zefan8910ae82014-04-03 14:46:29 -07001883 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +01001884 local_irq_restore(flags);
1885 return;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001886 } else {
Li Zefan8910ae82014-04-03 14:46:29 -07001887 kmemleak_enabled = 1;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001888 kmemleak_free_enabled = 1;
1889 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001890 local_irq_restore(flags);
1891
1892 /*
1893 * This is the point where tracking allocations is safe. Automatic
1894 * scanning is started during the late initcall. Add the early logged
1895 * callbacks to the kmemleak infrastructure.
1896 */
1897 for (i = 0; i < crt_early_log; i++) {
1898 struct early_log *log = &early_log[i];
1899
1900 switch (log->op_type) {
1901 case KMEMLEAK_ALLOC:
Catalin Marinasfd678962009-08-27 14:29:17 +01001902 early_alloc(log);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001903 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001904 case KMEMLEAK_ALLOC_PERCPU:
1905 early_alloc_percpu(log);
1906 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001907 case KMEMLEAK_FREE:
1908 kmemleak_free(log->ptr);
1909 break;
Catalin Marinas53238a62009-07-07 10:33:00 +01001910 case KMEMLEAK_FREE_PART:
1911 kmemleak_free_part(log->ptr, log->size);
1912 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001913 case KMEMLEAK_FREE_PERCPU:
1914 kmemleak_free_percpu(log->ptr);
1915 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001916 case KMEMLEAK_NOT_LEAK:
1917 kmemleak_not_leak(log->ptr);
1918 break;
1919 case KMEMLEAK_IGNORE:
1920 kmemleak_ignore(log->ptr);
1921 break;
1922 case KMEMLEAK_SCAN_AREA:
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001923 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001924 break;
1925 case KMEMLEAK_NO_SCAN:
1926 kmemleak_no_scan(log->ptr);
1927 break;
1928 default:
Catalin Marinas5f790202011-09-28 12:17:03 +01001929 kmemleak_warn("Unknown early log operation: %d\n",
1930 log->op_type);
1931 }
1932
Li Zefan8910ae82014-04-03 14:46:29 -07001933 if (kmemleak_warning) {
Catalin Marinas5f790202011-09-28 12:17:03 +01001934 print_log_trace(log);
Li Zefan8910ae82014-04-03 14:46:29 -07001935 kmemleak_warning = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001936 }
1937 }
1938}
1939
1940/*
1941 * Late initialization function.
1942 */
1943static int __init kmemleak_late_init(void)
1944{
1945 struct dentry *dentry;
1946
Li Zefan8910ae82014-04-03 14:46:29 -07001947 kmemleak_initialized = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001948
Li Zefan8910ae82014-04-03 14:46:29 -07001949 if (kmemleak_error) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001950 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001951 * Some error occurred and kmemleak was disabled. There is a
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001952 * small chance that kmemleak_disable() was called immediately
1953 * after setting kmemleak_initialized and we may end up with
1954 * two clean-up threads but serialized by scan_mutex.
1955 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001956 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001957 return -ENOMEM;
1958 }
1959
1960 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
1961 &kmemleak_fops);
1962 if (!dentry)
Joe Perchesae281062009-06-23 14:40:26 +01001963 pr_warning("Failed to create the debugfs kmemleak file\n");
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001964 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001965 start_scan_thread();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001966 mutex_unlock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001967
1968 pr_info("Kernel memory leak detector initialized\n");
1969
1970 return 0;
1971}
1972late_initcall(kmemleak_late_init);