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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
Andreas Platschek22901c62016-12-12 16:42:01 -080022 * Documentation/dev-tools/kmemleak.rst.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010023 *
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>
Ingo Molnar3f07c012017-02-08 18:51:30 +010076#include <linux/sched/signal.h>
Ingo Molnar29930022017-02-08 18:51:36 +010077#include <linux/sched/task.h>
Ingo Molnar68db0cf2017-02-08 18:51:37 +010078#include <linux/sched/task_stack.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010079#include <linux/jiffies.h>
80#include <linux/delay.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040081#include <linux/export.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010082#include <linux/kthread.h>
Michel Lespinasse85d3a312012-10-08 16:31:27 -070083#include <linux/rbtree.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010084#include <linux/fs.h>
85#include <linux/debugfs.h>
86#include <linux/seq_file.h>
87#include <linux/cpumask.h>
88#include <linux/spinlock.h>
89#include <linux/mutex.h>
90#include <linux/rcupdate.h>
91#include <linux/stacktrace.h>
92#include <linux/cache.h>
93#include <linux/percpu.h>
94#include <linux/hardirq.h>
Catalin Marinas9099dae2016-10-11 13:55:11 -070095#include <linux/bootmem.h>
96#include <linux/pfn.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010097#include <linux/mmzone.h>
98#include <linux/slab.h>
99#include <linux/thread_info.h>
100#include <linux/err.h>
101#include <linux/uaccess.h>
102#include <linux/string.h>
103#include <linux/nodemask.h>
104#include <linux/mm.h>
Catalin Marinas179a8102009-09-07 10:14:42 +0100105#include <linux/workqueue.h>
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000106#include <linux/crc32.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100107
108#include <asm/sections.h>
109#include <asm/processor.h>
Arun Sharma600634972011-07-26 16:09:06 -0700110#include <linux/atomic.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100111
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -0800112#include <linux/kasan.h>
Pekka Enberg8e019362009-08-27 14:50:00 +0100113#include <linux/kmemcheck.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100114#include <linux/kmemleak.h>
Laura Abbott029aeff2011-11-15 23:49:09 +0000115#include <linux/memory_hotplug.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100116
117/*
118 * Kmemleak configuration and common defines.
119 */
120#define MAX_TRACE 16 /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100121#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100122#define SECS_FIRST_SCAN 60 /* delay before the first scan */
123#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
Catalin Marinasaf986032009-08-27 14:29:12 +0100124#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100125
126#define BYTES_PER_POINTER sizeof(void *)
127
Catalin Marinas216c04b2009-06-17 18:29:02 +0100128/* GFP bitmask for kmemleak internal allocations */
Vladimir Davydov20b5c302016-01-14 15:18:08 -0800129#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000130 __GFP_NORETRY | __GFP_NOMEMALLOC | \
131 __GFP_NOWARN)
Catalin Marinas216c04b2009-06-17 18:29:02 +0100132
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100133/* scanning area inside a memory block */
134struct kmemleak_scan_area {
135 struct hlist_node node;
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000136 unsigned long start;
137 size_t size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100138};
139
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700140#define KMEMLEAK_GREY 0
141#define KMEMLEAK_BLACK -1
142
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100143/*
144 * Structure holding the metadata for each allocated memory block.
145 * Modifications to such objects should be made while holding the
146 * object->lock. Insertions or deletions from object_list, gray_list or
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700147 * rb_node are already protected by the corresponding locks or mutex (see
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100148 * the notes on locking above). These objects are reference-counted
149 * (use_count) and freed using the RCU mechanism.
150 */
151struct kmemleak_object {
152 spinlock_t lock;
153 unsigned long flags; /* object status flags */
154 struct list_head object_list;
155 struct list_head gray_list;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700156 struct rb_node rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100157 struct rcu_head rcu; /* object_list lockless traversal */
158 /* object usage count; object freed when use_count == 0 */
159 atomic_t use_count;
160 unsigned long pointer;
161 size_t size;
162 /* minimum number of a pointers found before it is considered leak */
163 int min_count;
164 /* the total number of pointers found pointing to this object */
165 int count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000166 /* checksum for detecting modified objects */
167 u32 checksum;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100168 /* memory ranges to be scanned inside an object (empty for all) */
169 struct hlist_head area_list;
170 unsigned long trace[MAX_TRACE];
171 unsigned int trace_len;
172 unsigned long jiffies; /* creation timestamp */
173 pid_t pid; /* pid of the current task */
174 char comm[TASK_COMM_LEN]; /* executable name */
175};
176
177/* flag representing the memory block allocation status */
178#define OBJECT_ALLOCATED (1 << 0)
179/* flag set after the first reporting of an unreference object */
180#define OBJECT_REPORTED (1 << 1)
181/* flag set to not scan the object */
182#define OBJECT_NO_SCAN (1 << 2)
183
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100184/* number of bytes to print per line; must be 16 or 32 */
185#define HEX_ROW_SIZE 16
186/* number of bytes to print at a time (1, 2, 4, 8) */
187#define HEX_GROUP_SIZE 1
188/* include ASCII after the hex output */
189#define HEX_ASCII 1
190/* max number of lines to be printed */
191#define HEX_MAX_LINES 2
192
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100193/* the list of all allocated objects */
194static LIST_HEAD(object_list);
195/* the list of gray-colored objects (see color_gray comment below) */
196static LIST_HEAD(gray_list);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700197/* search tree for object boundaries */
198static struct rb_root object_tree_root = RB_ROOT;
199/* rw_lock protecting the access to object_list and object_tree_root */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100200static DEFINE_RWLOCK(kmemleak_lock);
201
202/* allocation caches for kmemleak internal data */
203static struct kmem_cache *object_cache;
204static struct kmem_cache *scan_area_cache;
205
206/* set if tracing memory operations is enabled */
Li Zefan8910ae82014-04-03 14:46:29 -0700207static int kmemleak_enabled;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700208/* same as above but only for the kmemleak_free() callback */
209static int kmemleak_free_enabled;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100210/* set in the late_initcall if there were no errors */
Li Zefan8910ae82014-04-03 14:46:29 -0700211static int kmemleak_initialized;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100212/* enables or disables early logging of the memory operations */
Li Zefan8910ae82014-04-03 14:46:29 -0700213static int kmemleak_early_log = 1;
Catalin Marinas5f790202011-09-28 12:17:03 +0100214/* set if a kmemleak warning was issued */
Li Zefan8910ae82014-04-03 14:46:29 -0700215static int kmemleak_warning;
Catalin Marinas5f790202011-09-28 12:17:03 +0100216/* set if a fatal kmemleak error has occurred */
Li Zefan8910ae82014-04-03 14:46:29 -0700217static int kmemleak_error;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100218
219/* minimum and maximum address that may be valid pointers */
220static unsigned long min_addr = ULONG_MAX;
221static unsigned long max_addr;
222
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100223static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100224/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100225static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100226static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100227/* delay between automatic memory scannings */
228static signed long jiffies_scan_wait;
229/* enables or disables the task stacks scanning */
Catalin Marinase0a2a162009-06-26 17:38:25 +0100230static int kmemleak_stack_scan = 1;
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100231/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100232static DEFINE_MUTEX(scan_mutex);
Jason Baronab0155a2010-07-19 11:54:17 +0100233/* setting kmemleak=on, will set this var, skipping the disable */
234static int kmemleak_skip_disable;
Li Zefandc9b3f42014-04-03 14:46:26 -0700235/* If there are leaks that can be reported */
236static bool kmemleak_found_leaks;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100237
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100238/*
Catalin Marinas20301172009-06-17 18:29:04 +0100239 * Early object allocation/freeing logging. Kmemleak is initialized after the
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100240 * kernel allocator. However, both the kernel allocator and kmemleak may
Catalin Marinas20301172009-06-17 18:29:04 +0100241 * allocate memory blocks which need to be tracked. Kmemleak defines an
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100242 * arbitrary buffer to hold the allocation/freeing information before it is
243 * fully initialized.
244 */
245
246/* kmemleak operation type for early logging */
247enum {
248 KMEMLEAK_ALLOC,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100249 KMEMLEAK_ALLOC_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100250 KMEMLEAK_FREE,
Catalin Marinas53238a62009-07-07 10:33:00 +0100251 KMEMLEAK_FREE_PART,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100252 KMEMLEAK_FREE_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100253 KMEMLEAK_NOT_LEAK,
254 KMEMLEAK_IGNORE,
255 KMEMLEAK_SCAN_AREA,
256 KMEMLEAK_NO_SCAN
257};
258
259/*
260 * Structure holding the information passed to kmemleak callbacks during the
261 * early logging.
262 */
263struct early_log {
264 int op_type; /* kmemleak operation type */
265 const void *ptr; /* allocated/freed memory block */
266 size_t size; /* memory block size */
267 int min_count; /* minimum reference count */
Catalin Marinasfd678962009-08-27 14:29:17 +0100268 unsigned long trace[MAX_TRACE]; /* stack trace */
269 unsigned int trace_len; /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100270};
271
272/* early logging buffer and current position */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100273static struct early_log
274 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
275static int crt_early_log __initdata;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100276
277static void kmemleak_disable(void);
278
279/*
280 * Print a warning and dump the stack trace.
281 */
Catalin Marinas5f790202011-09-28 12:17:03 +0100282#define kmemleak_warn(x...) do { \
Joe Perches598d8092016-03-17 14:19:44 -0700283 pr_warn(x); \
Catalin Marinas5f790202011-09-28 12:17:03 +0100284 dump_stack(); \
Li Zefan8910ae82014-04-03 14:46:29 -0700285 kmemleak_warning = 1; \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100286} while (0)
287
288/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300289 * Macro invoked when a serious kmemleak condition occurred and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100290 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100291 * tracing no longer available.
292 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100293#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100294 kmemleak_warn(x); \
295 kmemleak_disable(); \
296} while (0)
297
298/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100299 * Printing of the objects hex dump to the seq file. The number of lines to be
300 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
301 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
302 * with the object->lock held.
303 */
304static void hex_dump_object(struct seq_file *seq,
305 struct kmemleak_object *object)
306{
307 const u8 *ptr = (const u8 *)object->pointer;
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700308 size_t len;
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100309
310 /* limit the number of lines to HEX_MAX_LINES */
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700311 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100312
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700313 seq_printf(seq, " hex dump (first %zu bytes):\n", len);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700314 kasan_disable_current();
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700315 seq_hex_dump(seq, " ", DUMP_PREFIX_NONE, HEX_ROW_SIZE,
316 HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700317 kasan_enable_current();
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100318}
319
320/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100321 * Object colors, encoded with count and min_count:
322 * - white - orphan object, not enough references to it (count < min_count)
323 * - gray - not orphan, not marked as false positive (min_count == 0) or
324 * sufficient references to it (count >= min_count)
325 * - black - ignore, it doesn't contain references (e.g. text section)
326 * (min_count == -1). No function defined for this color.
327 * Newly created objects don't have any color assigned (object->count == -1)
328 * before the next memory scan when they become white.
329 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100330static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100331{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700332 return object->count != KMEMLEAK_BLACK &&
333 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100334}
335
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100336static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100337{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700338 return object->min_count != KMEMLEAK_BLACK &&
339 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100340}
341
342/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100343 * Objects are considered unreferenced only if their color is white, they have
344 * not be deleted and have a minimum age to avoid false positives caused by
345 * pointers temporarily stored in CPU registers.
346 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100347static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100348{
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000349 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100350 time_before_eq(object->jiffies + jiffies_min_age,
351 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100352}
353
354/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100355 * Printing of the unreferenced objects information to the seq file. The
356 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100357 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100358static void print_unreferenced(struct seq_file *seq,
359 struct kmemleak_object *object)
360{
361 int i;
Catalin Marinasfefdd332009-10-28 13:33:12 +0000362 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100363
Catalin Marinasbab4a342009-06-26 17:38:26 +0100364 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
365 object->pointer, object->size);
Catalin Marinasfefdd332009-10-28 13:33:12 +0000366 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
367 object->comm, object->pid, object->jiffies,
368 msecs_age / 1000, msecs_age % 1000);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100369 hex_dump_object(seq, object);
Catalin Marinasbab4a342009-06-26 17:38:26 +0100370 seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100371
372 for (i = 0; i < object->trace_len; i++) {
373 void *ptr = (void *)object->trace[i];
Catalin Marinasbab4a342009-06-26 17:38:26 +0100374 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100375 }
376}
377
378/*
379 * Print the kmemleak_object information. This function is used mainly for
380 * debugging special cases when kmemleak operations. It must be called with
381 * the object->lock held.
382 */
383static void dump_object_info(struct kmemleak_object *object)
384{
385 struct stack_trace trace;
386
387 trace.nr_entries = object->trace_len;
388 trace.entries = object->trace;
389
Joe Perchesae281062009-06-23 14:40:26 +0100390 pr_notice("Object 0x%08lx (size %zu):\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700391 object->pointer, object->size);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100392 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
393 object->comm, object->pid, object->jiffies);
394 pr_notice(" min_count = %d\n", object->min_count);
395 pr_notice(" count = %d\n", object->count);
Catalin Marinas189d84e2009-08-27 14:29:15 +0100396 pr_notice(" flags = 0x%lx\n", object->flags);
Jianpeng Maaae0ad72014-06-06 14:38:16 -0700397 pr_notice(" checksum = %u\n", object->checksum);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100398 pr_notice(" backtrace:\n");
399 print_stack_trace(&trace, 4);
400}
401
402/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700403 * Look-up a memory block metadata (kmemleak_object) in the object search
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100404 * tree based on a pointer value. If alias is 0, only values pointing to the
405 * beginning of the memory block are allowed. The kmemleak_lock must be held
406 * when calling this function.
407 */
408static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
409{
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700410 struct rb_node *rb = object_tree_root.rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100411
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700412 while (rb) {
413 struct kmemleak_object *object =
414 rb_entry(rb, struct kmemleak_object, rb_node);
415 if (ptr < object->pointer)
416 rb = object->rb_node.rb_left;
417 else if (object->pointer + object->size <= ptr)
418 rb = object->rb_node.rb_right;
419 else if (object->pointer == ptr || alias)
420 return object;
421 else {
Catalin Marinas5f790202011-09-28 12:17:03 +0100422 kmemleak_warn("Found object by alias at 0x%08lx\n",
423 ptr);
Catalin Marinasa7686a42010-07-19 11:54:16 +0100424 dump_object_info(object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700425 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100426 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700427 }
428 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100429}
430
431/*
432 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
433 * that once an object's use_count reached 0, the RCU freeing was already
434 * registered and the object should no longer be used. This function must be
435 * called under the protection of rcu_read_lock().
436 */
437static int get_object(struct kmemleak_object *object)
438{
439 return atomic_inc_not_zero(&object->use_count);
440}
441
442/*
443 * RCU callback to free a kmemleak_object.
444 */
445static void free_object_rcu(struct rcu_head *rcu)
446{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800447 struct hlist_node *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100448 struct kmemleak_scan_area *area;
449 struct kmemleak_object *object =
450 container_of(rcu, struct kmemleak_object, rcu);
451
452 /*
453 * Once use_count is 0 (guaranteed by put_object), there is no other
454 * code accessing this object, hence no need for locking.
455 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800456 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
457 hlist_del(&area->node);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100458 kmem_cache_free(scan_area_cache, area);
459 }
460 kmem_cache_free(object_cache, object);
461}
462
463/*
464 * Decrement the object use_count. Once the count is 0, free the object using
465 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
466 * delete_object() path, the delayed RCU freeing ensures that there is no
467 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
468 * is also possible.
469 */
470static void put_object(struct kmemleak_object *object)
471{
472 if (!atomic_dec_and_test(&object->use_count))
473 return;
474
475 /* should only get here after delete_object was called */
476 WARN_ON(object->flags & OBJECT_ALLOCATED);
477
478 call_rcu(&object->rcu, free_object_rcu);
479}
480
481/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700482 * Look up an object in the object search tree and increase its use_count.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100483 */
484static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
485{
486 unsigned long flags;
Alexey Klimov9fbed252015-11-05 18:45:57 -0800487 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100488
489 rcu_read_lock();
490 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -0700491 object = lookup_object(ptr, alias);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100492 read_unlock_irqrestore(&kmemleak_lock, flags);
493
494 /* check whether the object is still available */
495 if (object && !get_object(object))
496 object = NULL;
497 rcu_read_unlock();
498
499 return object;
500}
501
502/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700503 * Look up an object in the object search tree and remove it from both
504 * object_tree_root and object_list. The returned object's use_count should be
505 * at least 1, as initially set by create_object().
506 */
507static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
508{
509 unsigned long flags;
510 struct kmemleak_object *object;
511
512 write_lock_irqsave(&kmemleak_lock, flags);
513 object = lookup_object(ptr, alias);
514 if (object) {
515 rb_erase(&object->rb_node, &object_tree_root);
516 list_del_rcu(&object->object_list);
517 }
518 write_unlock_irqrestore(&kmemleak_lock, flags);
519
520 return object;
521}
522
523/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100524 * Save stack trace to the given array of MAX_TRACE size.
525 */
526static int __save_stack_trace(unsigned long *trace)
527{
528 struct stack_trace stack_trace;
529
530 stack_trace.max_entries = MAX_TRACE;
531 stack_trace.nr_entries = 0;
532 stack_trace.entries = trace;
533 stack_trace.skip = 2;
534 save_stack_trace(&stack_trace);
535
536 return stack_trace.nr_entries;
537}
538
539/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100540 * Create the metadata (struct kmemleak_object) corresponding to an allocated
541 * memory block and add it to the object_list and object_tree_root.
542 */
Catalin Marinasfd678962009-08-27 14:29:17 +0100543static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
544 int min_count, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100545{
546 unsigned long flags;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700547 struct kmemleak_object *object, *parent;
548 struct rb_node **link, *rb_parent;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100549
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000550 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100551 if (!object) {
Joe Perches598d8092016-03-17 14:19:44 -0700552 pr_warn("Cannot allocate a kmemleak_object structure\n");
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000553 kmemleak_disable();
Catalin Marinasfd678962009-08-27 14:29:17 +0100554 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100555 }
556
557 INIT_LIST_HEAD(&object->object_list);
558 INIT_LIST_HEAD(&object->gray_list);
559 INIT_HLIST_HEAD(&object->area_list);
560 spin_lock_init(&object->lock);
561 atomic_set(&object->use_count, 1);
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000562 object->flags = OBJECT_ALLOCATED;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100563 object->pointer = ptr;
564 object->size = size;
565 object->min_count = min_count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000566 object->count = 0; /* white color initially */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100567 object->jiffies = jiffies;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000568 object->checksum = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100569
570 /* task information */
571 if (in_irq()) {
572 object->pid = 0;
573 strncpy(object->comm, "hardirq", sizeof(object->comm));
574 } else if (in_softirq()) {
575 object->pid = 0;
576 strncpy(object->comm, "softirq", sizeof(object->comm));
577 } else {
578 object->pid = current->pid;
579 /*
580 * There is a small chance of a race with set_task_comm(),
581 * however using get_task_comm() here may cause locking
582 * dependency issues with current->alloc_lock. In the worst
583 * case, the command line is not correct.
584 */
585 strncpy(object->comm, current->comm, sizeof(object->comm));
586 }
587
588 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100589 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100590
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100591 write_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100592
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100593 min_addr = min(min_addr, ptr);
594 max_addr = max(max_addr, ptr + size);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700595 link = &object_tree_root.rb_node;
596 rb_parent = NULL;
597 while (*link) {
598 rb_parent = *link;
599 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
600 if (ptr + size <= parent->pointer)
601 link = &parent->rb_node.rb_left;
602 else if (parent->pointer + parent->size <= ptr)
603 link = &parent->rb_node.rb_right;
604 else {
Joe Perches756a0252016-03-17 14:19:47 -0700605 kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700606 ptr);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700607 /*
608 * No need for parent->lock here since "parent" cannot
609 * be freed while the kmemleak_lock is held.
610 */
611 dump_object_info(parent);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700612 kmem_cache_free(object_cache, object);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700613 object = NULL;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700614 goto out;
615 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100616 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700617 rb_link_node(&object->rb_node, rb_parent, link);
618 rb_insert_color(&object->rb_node, &object_tree_root);
619
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100620 list_add_tail_rcu(&object->object_list, &object_list);
621out:
622 write_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinasfd678962009-08-27 14:29:17 +0100623 return object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100624}
625
626/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700627 * Mark the object as not allocated and schedule RCU freeing via put_object().
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100628 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100629static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100630{
631 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100632
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100633 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinase781a9a2015-06-24 16:58:29 -0700634 WARN_ON(atomic_read(&object->use_count) < 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100635
636 /*
637 * Locking here also ensures that the corresponding memory block
638 * cannot be freed when it is being scanned.
639 */
640 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100641 object->flags &= ~OBJECT_ALLOCATED;
642 spin_unlock_irqrestore(&object->lock, flags);
643 put_object(object);
644}
645
646/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100647 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
648 * delete it.
649 */
650static void delete_object_full(unsigned long ptr)
651{
652 struct kmemleak_object *object;
653
Catalin Marinase781a9a2015-06-24 16:58:29 -0700654 object = find_and_remove_object(ptr, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100655 if (!object) {
656#ifdef DEBUG
657 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
658 ptr);
659#endif
660 return;
661 }
662 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100663}
664
665/*
666 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
667 * delete it. If the memory block is partially freed, the function may create
668 * additional metadata for the remaining parts of the block.
669 */
670static void delete_object_part(unsigned long ptr, size_t size)
671{
672 struct kmemleak_object *object;
673 unsigned long start, end;
674
Catalin Marinase781a9a2015-06-24 16:58:29 -0700675 object = find_and_remove_object(ptr, 1);
Catalin Marinas53238a62009-07-07 10:33:00 +0100676 if (!object) {
677#ifdef DEBUG
Joe Perches756a0252016-03-17 14:19:47 -0700678 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
679 ptr, size);
Catalin Marinas53238a62009-07-07 10:33:00 +0100680#endif
681 return;
682 }
Catalin Marinas53238a62009-07-07 10:33:00 +0100683
684 /*
685 * Create one or two objects that may result from the memory block
686 * split. Note that partial freeing is only done by free_bootmem() and
687 * this happens before kmemleak_init() is called. The path below is
688 * only executed during early log recording in kmemleak_init(), so
689 * GFP_KERNEL is enough.
690 */
691 start = object->pointer;
692 end = object->pointer + object->size;
693 if (ptr > start)
694 create_object(start, ptr - start, object->min_count,
695 GFP_KERNEL);
696 if (ptr + size < end)
697 create_object(ptr + size, end - ptr - size, object->min_count,
698 GFP_KERNEL);
699
Catalin Marinase781a9a2015-06-24 16:58:29 -0700700 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100701}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700702
703static void __paint_it(struct kmemleak_object *object, int color)
704{
705 object->min_count = color;
706 if (color == KMEMLEAK_BLACK)
707 object->flags |= OBJECT_NO_SCAN;
708}
709
710static void paint_it(struct kmemleak_object *object, int color)
711{
712 unsigned long flags;
713
714 spin_lock_irqsave(&object->lock, flags);
715 __paint_it(object, color);
716 spin_unlock_irqrestore(&object->lock, flags);
717}
718
719static void paint_ptr(unsigned long ptr, int color)
720{
721 struct kmemleak_object *object;
722
723 object = find_and_get_object(ptr, 0);
724 if (!object) {
Joe Perches756a0252016-03-17 14:19:47 -0700725 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
726 ptr,
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700727 (color == KMEMLEAK_GREY) ? "Grey" :
728 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
729 return;
730 }
731 paint_it(object, color);
732 put_object(object);
733}
734
Catalin Marinas53238a62009-07-07 10:33:00 +0100735/*
Holger Hans Peter Freyther145b64b2010-07-22 19:54:13 +0800736 * Mark an object permanently as gray-colored so that it can no longer be
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100737 * reported as a leak. This is used in general to mark a false positive.
738 */
739static void make_gray_object(unsigned long ptr)
740{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700741 paint_ptr(ptr, KMEMLEAK_GREY);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100742}
743
744/*
745 * Mark the object as black-colored so that it is ignored from scans and
746 * reporting.
747 */
748static void make_black_object(unsigned long ptr)
749{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700750 paint_ptr(ptr, KMEMLEAK_BLACK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100751}
752
753/*
754 * Add a scanning area to the object. If at least one such area is added,
755 * kmemleak will only scan these ranges rather than the whole memory block.
756 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000757static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100758{
759 unsigned long flags;
760 struct kmemleak_object *object;
761 struct kmemleak_scan_area *area;
762
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000763 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100764 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100765 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
766 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100767 return;
768 }
769
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000770 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100771 if (!area) {
Joe Perches598d8092016-03-17 14:19:44 -0700772 pr_warn("Cannot allocate a scan area\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100773 goto out;
774 }
775
776 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas7f88f882013-11-12 15:07:45 -0800777 if (size == SIZE_MAX) {
778 size = object->pointer + object->size - ptr;
779 } else if (ptr + size > object->pointer + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100780 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100781 dump_object_info(object);
782 kmem_cache_free(scan_area_cache, area);
783 goto out_unlock;
784 }
785
786 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000787 area->start = ptr;
788 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100789
790 hlist_add_head(&area->node, &object->area_list);
791out_unlock:
792 spin_unlock_irqrestore(&object->lock, flags);
793out:
794 put_object(object);
795}
796
797/*
798 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
799 * pointer. Such object will not be scanned by kmemleak but references to it
800 * are searched.
801 */
802static void object_no_scan(unsigned long ptr)
803{
804 unsigned long flags;
805 struct kmemleak_object *object;
806
807 object = find_and_get_object(ptr, 0);
808 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100809 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100810 return;
811 }
812
813 spin_lock_irqsave(&object->lock, flags);
814 object->flags |= OBJECT_NO_SCAN;
815 spin_unlock_irqrestore(&object->lock, flags);
816 put_object(object);
817}
818
819/*
820 * Log an early kmemleak_* call to the early_log buffer. These calls will be
821 * processed later once kmemleak is fully initialized.
822 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100823static void __init log_early(int op_type, const void *ptr, size_t size,
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000824 int min_count)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100825{
826 unsigned long flags;
827 struct early_log *log;
828
Li Zefan8910ae82014-04-03 14:46:29 -0700829 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +0100830 /* kmemleak stopped recording, just count the requests */
831 crt_early_log++;
832 return;
833 }
834
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100835 if (crt_early_log >= ARRAY_SIZE(early_log)) {
Wang Kai21cd3a62015-09-08 15:03:41 -0700836 crt_early_log++;
Catalin Marinasa9d90582009-06-25 10:16:11 +0100837 kmemleak_disable();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100838 return;
839 }
840
841 /*
842 * There is no need for locking since the kernel is still in UP mode
843 * at this stage. Disabling the IRQs is enough.
844 */
845 local_irq_save(flags);
846 log = &early_log[crt_early_log];
847 log->op_type = op_type;
848 log->ptr = ptr;
849 log->size = size;
850 log->min_count = min_count;
Catalin Marinas5f790202011-09-28 12:17:03 +0100851 log->trace_len = __save_stack_trace(log->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100852 crt_early_log++;
853 local_irq_restore(flags);
854}
855
856/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100857 * Log an early allocated block and populate the stack trace.
858 */
859static void early_alloc(struct early_log *log)
860{
861 struct kmemleak_object *object;
862 unsigned long flags;
863 int i;
864
Li Zefan8910ae82014-04-03 14:46:29 -0700865 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
Catalin Marinasfd678962009-08-27 14:29:17 +0100866 return;
867
868 /*
869 * RCU locking needed to ensure object is not freed via put_object().
870 */
871 rcu_read_lock();
872 object = create_object((unsigned long)log->ptr, log->size,
Tetsuo Handac1bcd6b2009-10-09 10:39:24 +0100873 log->min_count, GFP_ATOMIC);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100874 if (!object)
875 goto out;
Catalin Marinasfd678962009-08-27 14:29:17 +0100876 spin_lock_irqsave(&object->lock, flags);
877 for (i = 0; i < log->trace_len; i++)
878 object->trace[i] = log->trace[i];
879 object->trace_len = log->trace_len;
880 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100881out:
Catalin Marinasfd678962009-08-27 14:29:17 +0100882 rcu_read_unlock();
883}
884
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100885/*
886 * Log an early allocated block and populate the stack trace.
887 */
888static void early_alloc_percpu(struct early_log *log)
889{
890 unsigned int cpu;
891 const void __percpu *ptr = log->ptr;
892
893 for_each_possible_cpu(cpu) {
894 log->ptr = per_cpu_ptr(ptr, cpu);
895 early_alloc(log);
896 }
897}
898
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100899/**
900 * kmemleak_alloc - register a newly allocated object
901 * @ptr: pointer to beginning of the object
902 * @size: size of the object
903 * @min_count: minimum number of references to this object. If during memory
904 * scanning a number of references less than @min_count is found,
905 * the object is reported as a memory leak. If @min_count is 0,
906 * the object is never reported as a leak. If @min_count is -1,
907 * the object is ignored (not scanned and not reported as a leak)
908 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
909 *
910 * This function is called from the kernel allocators when a new object
911 * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100912 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100913void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
914 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100915{
916 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
917
Li Zefan8910ae82014-04-03 14:46:29 -0700918 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100919 create_object((unsigned long)ptr, size, min_count, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700920 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000921 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100922}
923EXPORT_SYMBOL_GPL(kmemleak_alloc);
924
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100925/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100926 * kmemleak_alloc_percpu - register a newly allocated __percpu object
927 * @ptr: __percpu pointer to beginning of the object
928 * @size: size of the object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700929 * @gfp: flags used for kmemleak internal memory allocations
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100930 *
931 * This function is called from the kernel percpu allocator when a new object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700932 * (memory block) is allocated (alloc_percpu).
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100933 */
Larry Finger8a8c35f2015-06-24 16:58:51 -0700934void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
935 gfp_t gfp)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100936{
937 unsigned int cpu;
938
939 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
940
941 /*
942 * Percpu allocations are only scanned and not reported as leaks
943 * (min_count is set to 0).
944 */
Li Zefan8910ae82014-04-03 14:46:29 -0700945 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100946 for_each_possible_cpu(cpu)
947 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
Larry Finger8a8c35f2015-06-24 16:58:51 -0700948 size, 0, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700949 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100950 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
951}
952EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
953
954/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100955 * kmemleak_free - unregister a previously registered object
956 * @ptr: pointer to beginning of the object
957 *
958 * This function is called from the kernel allocators when an object (memory
959 * block) is freed (kmem_cache_free, kfree, vfree etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100960 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100961void __ref kmemleak_free(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100962{
963 pr_debug("%s(0x%p)\n", __func__, ptr);
964
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700965 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +0100966 delete_object_full((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -0700967 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000968 log_early(KMEMLEAK_FREE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100969}
970EXPORT_SYMBOL_GPL(kmemleak_free);
971
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100972/**
973 * kmemleak_free_part - partially unregister a previously registered object
974 * @ptr: pointer to the beginning or inside the object. This also
975 * represents the start of the range to be freed
976 * @size: size to be unregistered
977 *
978 * This function is called when only a part of a memory block is freed
979 * (usually from the bootmem allocator).
Catalin Marinas53238a62009-07-07 10:33:00 +0100980 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100981void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +0100982{
983 pr_debug("%s(0x%p)\n", __func__, ptr);
984
Li Zefan8910ae82014-04-03 14:46:29 -0700985 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +0100986 delete_object_part((unsigned long)ptr, size);
Li Zefan8910ae82014-04-03 14:46:29 -0700987 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000988 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100989}
990EXPORT_SYMBOL_GPL(kmemleak_free_part);
991
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100992/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100993 * kmemleak_free_percpu - unregister a previously registered __percpu object
994 * @ptr: __percpu pointer to beginning of the object
995 *
996 * This function is called from the kernel percpu allocator when an object
997 * (memory block) is freed (free_percpu).
998 */
999void __ref kmemleak_free_percpu(const void __percpu *ptr)
1000{
1001 unsigned int cpu;
1002
1003 pr_debug("%s(0x%p)\n", __func__, ptr);
1004
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001005 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001006 for_each_possible_cpu(cpu)
1007 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1008 cpu));
Li Zefan8910ae82014-04-03 14:46:29 -07001009 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001010 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1011}
1012EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1013
1014/**
Catalin Marinasffe2c742014-06-06 14:38:17 -07001015 * kmemleak_update_trace - update object allocation stack trace
1016 * @ptr: pointer to beginning of the object
1017 *
1018 * Override the object allocation stack trace for cases where the actual
1019 * allocation place is not always useful.
1020 */
1021void __ref kmemleak_update_trace(const void *ptr)
1022{
1023 struct kmemleak_object *object;
1024 unsigned long flags;
1025
1026 pr_debug("%s(0x%p)\n", __func__, ptr);
1027
1028 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1029 return;
1030
1031 object = find_and_get_object((unsigned long)ptr, 1);
1032 if (!object) {
1033#ifdef DEBUG
1034 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1035 ptr);
1036#endif
1037 return;
1038 }
1039
1040 spin_lock_irqsave(&object->lock, flags);
1041 object->trace_len = __save_stack_trace(object->trace);
1042 spin_unlock_irqrestore(&object->lock, flags);
1043
1044 put_object(object);
1045}
1046EXPORT_SYMBOL(kmemleak_update_trace);
1047
1048/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001049 * kmemleak_not_leak - mark an allocated object as false positive
1050 * @ptr: pointer to beginning of the object
1051 *
1052 * Calling this function on an object will cause the memory block to no longer
1053 * be reported as leak and always be scanned.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001054 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001055void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001056{
1057 pr_debug("%s(0x%p)\n", __func__, ptr);
1058
Li Zefan8910ae82014-04-03 14:46:29 -07001059 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001060 make_gray_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001061 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001062 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001063}
1064EXPORT_SYMBOL(kmemleak_not_leak);
1065
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001066/**
1067 * kmemleak_ignore - ignore an allocated object
1068 * @ptr: pointer to beginning of the object
1069 *
1070 * Calling this function on an object will cause the memory block to be
1071 * ignored (not scanned and not reported as a leak). This is usually done when
1072 * it is known that the corresponding block is not a leak and does not contain
1073 * any references to other allocated memory blocks.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001074 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001075void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001076{
1077 pr_debug("%s(0x%p)\n", __func__, ptr);
1078
Li Zefan8910ae82014-04-03 14:46:29 -07001079 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001080 make_black_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001081 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001082 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001083}
1084EXPORT_SYMBOL(kmemleak_ignore);
1085
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001086/**
1087 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1088 * @ptr: pointer to beginning or inside the object. This also
1089 * represents the start of the scan area
1090 * @size: size of the scan area
1091 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1092 *
1093 * This function is used when it is known that only certain parts of an object
1094 * contain references to other objects. Kmemleak will only scan these areas
1095 * reducing the number false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001096 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001097void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001098{
1099 pr_debug("%s(0x%p)\n", __func__, ptr);
1100
Li Zefan8910ae82014-04-03 14:46:29 -07001101 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001102 add_scan_area((unsigned long)ptr, size, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -07001103 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001104 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001105}
1106EXPORT_SYMBOL(kmemleak_scan_area);
1107
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001108/**
1109 * kmemleak_no_scan - do not scan an allocated object
1110 * @ptr: pointer to beginning of the object
1111 *
1112 * This function notifies kmemleak not to scan the given memory block. Useful
1113 * in situations where it is known that the given object does not contain any
1114 * references to other objects. Kmemleak will not scan such objects reducing
1115 * the number of false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001116 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001117void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001118{
1119 pr_debug("%s(0x%p)\n", __func__, ptr);
1120
Li Zefan8910ae82014-04-03 14:46:29 -07001121 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001122 object_no_scan((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001123 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001124 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001125}
1126EXPORT_SYMBOL(kmemleak_no_scan);
1127
Catalin Marinas9099dae2016-10-11 13:55:11 -07001128/**
1129 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1130 * address argument
1131 */
1132void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
1133 gfp_t gfp)
1134{
1135 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1136 kmemleak_alloc(__va(phys), size, min_count, gfp);
1137}
1138EXPORT_SYMBOL(kmemleak_alloc_phys);
1139
1140/**
1141 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1142 * physical address argument
1143 */
1144void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1145{
1146 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1147 kmemleak_free_part(__va(phys), size);
1148}
1149EXPORT_SYMBOL(kmemleak_free_part_phys);
1150
1151/**
1152 * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
1153 * address argument
1154 */
1155void __ref kmemleak_not_leak_phys(phys_addr_t phys)
1156{
1157 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1158 kmemleak_not_leak(__va(phys));
1159}
1160EXPORT_SYMBOL(kmemleak_not_leak_phys);
1161
1162/**
1163 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1164 * address argument
1165 */
1166void __ref kmemleak_ignore_phys(phys_addr_t phys)
1167{
1168 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1169 kmemleak_ignore(__va(phys));
1170}
1171EXPORT_SYMBOL(kmemleak_ignore_phys);
1172
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001173/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001174 * Update an object's checksum and return true if it was modified.
1175 */
1176static bool update_checksum(struct kmemleak_object *object)
1177{
1178 u32 old_csum = object->checksum;
1179
1180 if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
1181 return false;
1182
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001183 kasan_disable_current();
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001184 object->checksum = crc32(0, (void *)object->pointer, object->size);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001185 kasan_enable_current();
1186
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001187 return object->checksum != old_csum;
1188}
1189
1190/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001191 * Memory scanning is a long process and it needs to be interruptable. This
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001192 * function checks whether such interrupt condition occurred.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001193 */
1194static int scan_should_stop(void)
1195{
Li Zefan8910ae82014-04-03 14:46:29 -07001196 if (!kmemleak_enabled)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001197 return 1;
1198
1199 /*
1200 * This function may be called from either process or kthread context,
1201 * hence the need to check for both stop conditions.
1202 */
1203 if (current->mm)
1204 return signal_pending(current);
1205 else
1206 return kthread_should_stop();
1207
1208 return 0;
1209}
1210
1211/*
1212 * Scan a memory block (exclusive range) for valid pointers and add those
1213 * found to the gray list.
1214 */
1215static void scan_block(void *_start, void *_end,
Catalin Marinas93ada572015-06-24 16:58:37 -07001216 struct kmemleak_object *scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001217{
1218 unsigned long *ptr;
1219 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1220 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
Catalin Marinas93ada572015-06-24 16:58:37 -07001221 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001222
Catalin Marinas93ada572015-06-24 16:58:37 -07001223 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001224 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001225 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +01001226 unsigned long pointer;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001227
1228 if (scan_should_stop())
1229 break;
1230
Pekka Enberg8e019362009-08-27 14:50:00 +01001231 /* don't scan uninitialized memory */
1232 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
1233 BYTES_PER_POINTER))
1234 continue;
1235
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001236 kasan_disable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001237 pointer = *ptr;
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001238 kasan_enable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001239
Catalin Marinas93ada572015-06-24 16:58:37 -07001240 if (pointer < min_addr || pointer >= max_addr)
1241 continue;
1242
1243 /*
1244 * No need for get_object() here since we hold kmemleak_lock.
1245 * object->use_count cannot be dropped to 0 while the object
1246 * is still present in object_tree_root and object_list
1247 * (with updates protected by kmemleak_lock).
1248 */
1249 object = lookup_object(pointer, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001250 if (!object)
1251 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001252 if (object == scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001253 /* self referenced, ignore */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001254 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001255
1256 /*
1257 * Avoid the lockdep recursive warning on object->lock being
1258 * previously acquired in scan_object(). These locks are
1259 * enclosed by scan_mutex.
1260 */
Catalin Marinas93ada572015-06-24 16:58:37 -07001261 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001262 if (!color_white(object)) {
1263 /* non-orphan, ignored or new */
Catalin Marinas93ada572015-06-24 16:58:37 -07001264 spin_unlock(&object->lock);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001265 continue;
1266 }
1267
1268 /*
1269 * Increase the object's reference count (number of pointers
1270 * to the memory block). If this count reaches the required
1271 * minimum, the object's color will become gray and it will be
1272 * added to the gray_list.
1273 */
1274 object->count++;
Catalin Marinas0587da42009-10-28 13:33:11 +00001275 if (color_gray(object)) {
Catalin Marinas93ada572015-06-24 16:58:37 -07001276 /* put_object() called when removing from gray_list */
1277 WARN_ON(!get_object(object));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001278 list_add_tail(&object->gray_list, &gray_list);
Catalin Marinas0587da42009-10-28 13:33:11 +00001279 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001280 spin_unlock(&object->lock);
1281 }
1282 read_unlock_irqrestore(&kmemleak_lock, flags);
1283}
Catalin Marinas0587da42009-10-28 13:33:11 +00001284
Catalin Marinas93ada572015-06-24 16:58:37 -07001285/*
1286 * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1287 */
1288static void scan_large_block(void *start, void *end)
1289{
1290 void *next;
1291
1292 while (start < end) {
1293 next = min(start + MAX_SCAN_SIZE, end);
1294 scan_block(start, next, NULL);
1295 start = next;
1296 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001297 }
1298}
1299
1300/*
1301 * Scan a memory block corresponding to a kmemleak_object. A condition is
1302 * that object->use_count >= 1.
1303 */
1304static void scan_object(struct kmemleak_object *object)
1305{
1306 struct kmemleak_scan_area *area;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001307 unsigned long flags;
1308
1309 /*
Uwe Kleine-König21ae2952009-10-07 15:21:09 +02001310 * Once the object->lock is acquired, the corresponding memory block
1311 * cannot be freed (the same lock is acquired in delete_object).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001312 */
1313 spin_lock_irqsave(&object->lock, flags);
1314 if (object->flags & OBJECT_NO_SCAN)
1315 goto out;
1316 if (!(object->flags & OBJECT_ALLOCATED))
1317 /* already freed object */
1318 goto out;
Catalin Marinasaf986032009-08-27 14:29:12 +01001319 if (hlist_empty(&object->area_list)) {
1320 void *start = (void *)object->pointer;
1321 void *end = (void *)(object->pointer + object->size);
Catalin Marinas93ada572015-06-24 16:58:37 -07001322 void *next;
Catalin Marinasaf986032009-08-27 14:29:12 +01001323
Catalin Marinas93ada572015-06-24 16:58:37 -07001324 do {
1325 next = min(start + MAX_SCAN_SIZE, end);
1326 scan_block(start, next, object);
1327
1328 start = next;
1329 if (start >= end)
1330 break;
Catalin Marinasaf986032009-08-27 14:29:12 +01001331
1332 spin_unlock_irqrestore(&object->lock, flags);
1333 cond_resched();
1334 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -07001335 } while (object->flags & OBJECT_ALLOCATED);
Catalin Marinasaf986032009-08-27 14:29:12 +01001336 } else
Sasha Levinb67bfe02013-02-27 17:06:00 -08001337 hlist_for_each_entry(area, &object->area_list, node)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001338 scan_block((void *)area->start,
1339 (void *)(area->start + area->size),
Catalin Marinas93ada572015-06-24 16:58:37 -07001340 object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001341out:
1342 spin_unlock_irqrestore(&object->lock, flags);
1343}
1344
1345/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001346 * Scan the objects already referenced (gray objects). More objects will be
1347 * referenced and, if there are no memory leaks, all the objects are scanned.
1348 */
1349static void scan_gray_list(void)
1350{
1351 struct kmemleak_object *object, *tmp;
1352
1353 /*
1354 * The list traversal is safe for both tail additions and removals
1355 * from inside the loop. The kmemleak objects cannot be freed from
1356 * outside the loop because their use_count was incremented.
1357 */
1358 object = list_entry(gray_list.next, typeof(*object), gray_list);
1359 while (&object->gray_list != &gray_list) {
1360 cond_resched();
1361
1362 /* may add new objects to the list */
1363 if (!scan_should_stop())
1364 scan_object(object);
1365
1366 tmp = list_entry(object->gray_list.next, typeof(*object),
1367 gray_list);
1368
1369 /* remove the object from the list and release it */
1370 list_del(&object->gray_list);
1371 put_object(object);
1372
1373 object = tmp;
1374 }
1375 WARN_ON(!list_empty(&gray_list));
1376}
1377
1378/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001379 * Scan data sections and all the referenced memory blocks allocated via the
1380 * kernel's standard allocators. This function must be called with the
1381 * scan_mutex held.
1382 */
1383static void kmemleak_scan(void)
1384{
1385 unsigned long flags;
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001386 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001387 int i;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001388 int new_leaks = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001389
Catalin Marinasacf49682009-06-26 17:38:29 +01001390 jiffies_last_scan = jiffies;
1391
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001392 /* prepare the kmemleak_object's */
1393 rcu_read_lock();
1394 list_for_each_entry_rcu(object, &object_list, object_list) {
1395 spin_lock_irqsave(&object->lock, flags);
1396#ifdef DEBUG
1397 /*
1398 * With a few exceptions there should be a maximum of
1399 * 1 reference to any object at this point.
1400 */
1401 if (atomic_read(&object->use_count) > 1) {
Joe Perchesae281062009-06-23 14:40:26 +01001402 pr_debug("object->use_count = %d\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001403 atomic_read(&object->use_count));
1404 dump_object_info(object);
1405 }
1406#endif
1407 /* reset the reference count (whiten the object) */
1408 object->count = 0;
1409 if (color_gray(object) && get_object(object))
1410 list_add_tail(&object->gray_list, &gray_list);
1411
1412 spin_unlock_irqrestore(&object->lock, flags);
1413 }
1414 rcu_read_unlock();
1415
1416 /* data/bss scanning */
Catalin Marinas93ada572015-06-24 16:58:37 -07001417 scan_large_block(_sdata, _edata);
1418 scan_large_block(__bss_start, __bss_stop);
Kees Cook906f2a52017-03-31 15:11:58 -07001419 scan_large_block(__start_ro_after_init, __end_ro_after_init);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001420
1421#ifdef CONFIG_SMP
1422 /* per-cpu sections scanning */
1423 for_each_possible_cpu(i)
Catalin Marinas93ada572015-06-24 16:58:37 -07001424 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1425 __per_cpu_end + per_cpu_offset(i));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001426#endif
1427
1428 /*
Laura Abbott029aeff2011-11-15 23:49:09 +00001429 * Struct page scanning for each node.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001430 */
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001431 get_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001432 for_each_online_node(i) {
Cody P Schafer108bcc92013-02-22 16:35:23 -08001433 unsigned long start_pfn = node_start_pfn(i);
1434 unsigned long end_pfn = node_end_pfn(i);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001435 unsigned long pfn;
1436
1437 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1438 struct page *page;
1439
1440 if (!pfn_valid(pfn))
1441 continue;
1442 page = pfn_to_page(pfn);
1443 /* only scan if page is in use */
1444 if (page_count(page) == 0)
1445 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001446 scan_block(page, page + 1, NULL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001447 }
1448 }
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001449 put_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001450
1451 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001452 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001453 */
1454 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001455 struct task_struct *p, *g;
1456
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001457 read_lock(&tasklist_lock);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001458 do_each_thread(g, p) {
Catalin Marinas37df49f2016-10-27 17:46:47 -07001459 void *stack = try_get_task_stack(p);
1460 if (stack) {
1461 scan_block(stack, stack + THREAD_SIZE, NULL);
1462 put_task_stack(p);
1463 }
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001464 } while_each_thread(g, p);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001465 read_unlock(&tasklist_lock);
1466 }
1467
1468 /*
1469 * Scan the objects already referenced from the sections scanned
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001470 * above.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001471 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001472 scan_gray_list();
Catalin Marinas25873622009-07-07 10:32:58 +01001473
1474 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001475 * Check for new or unreferenced objects modified since the previous
1476 * scan and color them gray until the next scan.
Catalin Marinas25873622009-07-07 10:32:58 +01001477 */
1478 rcu_read_lock();
1479 list_for_each_entry_rcu(object, &object_list, object_list) {
1480 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001481 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1482 && update_checksum(object) && get_object(object)) {
1483 /* color it gray temporarily */
1484 object->count = object->min_count;
Catalin Marinas25873622009-07-07 10:32:58 +01001485 list_add_tail(&object->gray_list, &gray_list);
1486 }
1487 spin_unlock_irqrestore(&object->lock, flags);
1488 }
1489 rcu_read_unlock();
1490
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001491 /*
1492 * Re-scan the gray list for modified unreferenced objects.
1493 */
1494 scan_gray_list();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001495
1496 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001497 * If scanning was stopped do not report any new unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001498 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001499 if (scan_should_stop())
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001500 return;
1501
1502 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001503 * Scanning result reporting.
1504 */
1505 rcu_read_lock();
1506 list_for_each_entry_rcu(object, &object_list, object_list) {
1507 spin_lock_irqsave(&object->lock, flags);
1508 if (unreferenced_object(object) &&
1509 !(object->flags & OBJECT_REPORTED)) {
1510 object->flags |= OBJECT_REPORTED;
1511 new_leaks++;
1512 }
1513 spin_unlock_irqrestore(&object->lock, flags);
1514 }
1515 rcu_read_unlock();
1516
Li Zefandc9b3f42014-04-03 14:46:26 -07001517 if (new_leaks) {
1518 kmemleak_found_leaks = true;
1519
Joe Perches756a0252016-03-17 14:19:47 -07001520 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1521 new_leaks);
Li Zefandc9b3f42014-04-03 14:46:26 -07001522 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001523
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001524}
1525
1526/*
1527 * Thread function performing automatic memory scanning. Unreferenced objects
1528 * at the end of a memory scan are reported but only the first time.
1529 */
1530static int kmemleak_scan_thread(void *arg)
1531{
1532 static int first_run = 1;
1533
Joe Perchesae281062009-06-23 14:40:26 +01001534 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001535 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001536
1537 /*
1538 * Wait before the first scan to allow the system to fully initialize.
1539 */
1540 if (first_run) {
Vegard Nossum98c42d92016-07-28 15:48:32 -07001541 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001542 first_run = 0;
Vegard Nossum98c42d92016-07-28 15:48:32 -07001543 while (timeout && !kthread_should_stop())
1544 timeout = schedule_timeout_interruptible(timeout);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001545 }
1546
1547 while (!kthread_should_stop()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001548 signed long timeout = jiffies_scan_wait;
1549
1550 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001551 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001552 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001553
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001554 /* wait before the next scan */
1555 while (timeout && !kthread_should_stop())
1556 timeout = schedule_timeout_interruptible(timeout);
1557 }
1558
Joe Perchesae281062009-06-23 14:40:26 +01001559 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001560
1561 return 0;
1562}
1563
1564/*
1565 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001566 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001567 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001568static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001569{
1570 if (scan_thread)
1571 return;
1572 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1573 if (IS_ERR(scan_thread)) {
Joe Perches598d8092016-03-17 14:19:44 -07001574 pr_warn("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001575 scan_thread = NULL;
1576 }
1577}
1578
1579/*
1580 * Stop the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001581 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001582 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001583static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001584{
1585 if (scan_thread) {
1586 kthread_stop(scan_thread);
1587 scan_thread = NULL;
1588 }
1589}
1590
1591/*
1592 * Iterate over the object_list and return the first valid object at or after
1593 * the required position with its use_count incremented. The function triggers
1594 * a memory scanning when the pos argument points to the first position.
1595 */
1596static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1597{
1598 struct kmemleak_object *object;
1599 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001600 int err;
1601
1602 err = mutex_lock_interruptible(&scan_mutex);
1603 if (err < 0)
1604 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001605
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001606 rcu_read_lock();
1607 list_for_each_entry_rcu(object, &object_list, object_list) {
1608 if (n-- > 0)
1609 continue;
1610 if (get_object(object))
1611 goto out;
1612 }
1613 object = NULL;
1614out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001615 return object;
1616}
1617
1618/*
1619 * Return the next object in the object_list. The function decrements the
1620 * use_count of the previous object and increases that of the next one.
1621 */
1622static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1623{
1624 struct kmemleak_object *prev_obj = v;
1625 struct kmemleak_object *next_obj = NULL;
Michael Wang58fac092012-08-17 12:33:34 +08001626 struct kmemleak_object *obj = prev_obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001627
1628 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001629
Michael Wang58fac092012-08-17 12:33:34 +08001630 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001631 if (get_object(obj)) {
1632 next_obj = obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001633 break;
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001634 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001635 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001636
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001637 put_object(prev_obj);
1638 return next_obj;
1639}
1640
1641/*
1642 * Decrement the use_count of the last object required, if any.
1643 */
1644static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1645{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001646 if (!IS_ERR(v)) {
1647 /*
1648 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1649 * waiting was interrupted, so only release it if !IS_ERR.
1650 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001651 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001652 mutex_unlock(&scan_mutex);
1653 if (v)
1654 put_object(v);
1655 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001656}
1657
1658/*
1659 * Print the information for an unreferenced object to the seq file.
1660 */
1661static int kmemleak_seq_show(struct seq_file *seq, void *v)
1662{
1663 struct kmemleak_object *object = v;
1664 unsigned long flags;
1665
1666 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001667 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001668 print_unreferenced(seq, object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001669 spin_unlock_irqrestore(&object->lock, flags);
1670 return 0;
1671}
1672
1673static const struct seq_operations kmemleak_seq_ops = {
1674 .start = kmemleak_seq_start,
1675 .next = kmemleak_seq_next,
1676 .stop = kmemleak_seq_stop,
1677 .show = kmemleak_seq_show,
1678};
1679
1680static int kmemleak_open(struct inode *inode, struct file *file)
1681{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001682 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001683}
1684
Catalin Marinas189d84e2009-08-27 14:29:15 +01001685static int dump_str_object_info(const char *str)
1686{
1687 unsigned long flags;
1688 struct kmemleak_object *object;
1689 unsigned long addr;
1690
Abhijit Pawardc053732012-12-18 14:23:27 -08001691 if (kstrtoul(str, 0, &addr))
1692 return -EINVAL;
Catalin Marinas189d84e2009-08-27 14:29:15 +01001693 object = find_and_get_object(addr, 0);
1694 if (!object) {
1695 pr_info("Unknown object at 0x%08lx\n", addr);
1696 return -EINVAL;
1697 }
1698
1699 spin_lock_irqsave(&object->lock, flags);
1700 dump_object_info(object);
1701 spin_unlock_irqrestore(&object->lock, flags);
1702
1703 put_object(object);
1704 return 0;
1705}
1706
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001707/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001708 * We use grey instead of black to ensure we can do future scans on the same
1709 * objects. If we did not do future scans these black objects could
1710 * potentially contain references to newly allocated objects in the future and
1711 * we'd end up with false positives.
1712 */
1713static void kmemleak_clear(void)
1714{
1715 struct kmemleak_object *object;
1716 unsigned long flags;
1717
1718 rcu_read_lock();
1719 list_for_each_entry_rcu(object, &object_list, object_list) {
1720 spin_lock_irqsave(&object->lock, flags);
1721 if ((object->flags & OBJECT_REPORTED) &&
1722 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001723 __paint_it(object, KMEMLEAK_GREY);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001724 spin_unlock_irqrestore(&object->lock, flags);
1725 }
1726 rcu_read_unlock();
Li Zefandc9b3f42014-04-03 14:46:26 -07001727
1728 kmemleak_found_leaks = false;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001729}
1730
Li Zefanc89da702014-04-03 14:46:27 -07001731static void __kmemleak_do_cleanup(void);
1732
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001733/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001734 * File write operation to configure kmemleak at run-time. The following
1735 * commands can be written to the /sys/kernel/debug/kmemleak file:
1736 * off - disable kmemleak (irreversible)
1737 * stack=on - enable the task stacks scanning
1738 * stack=off - disable the tasks stacks scanning
1739 * scan=on - start the automatic memory scanning thread
1740 * scan=off - stop the automatic memory scanning thread
1741 * scan=... - set the automatic memory scanning period in seconds (0 to
1742 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001743 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001744 * clear - mark all current reported unreferenced kmemleak objects as
Li Zefanc89da702014-04-03 14:46:27 -07001745 * grey to ignore printing them, or free all kmemleak objects
1746 * if kmemleak has been disabled.
Catalin Marinas189d84e2009-08-27 14:29:15 +01001747 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001748 */
1749static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1750 size_t size, loff_t *ppos)
1751{
1752 char buf[64];
1753 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001754 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001755
1756 buf_size = min(size, (sizeof(buf) - 1));
1757 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1758 return -EFAULT;
1759 buf[buf_size] = 0;
1760
Catalin Marinasb87324d2009-07-07 10:32:58 +01001761 ret = mutex_lock_interruptible(&scan_mutex);
1762 if (ret < 0)
1763 return ret;
1764
Li Zefanc89da702014-04-03 14:46:27 -07001765 if (strncmp(buf, "clear", 5) == 0) {
Li Zefan8910ae82014-04-03 14:46:29 -07001766 if (kmemleak_enabled)
Li Zefanc89da702014-04-03 14:46:27 -07001767 kmemleak_clear();
1768 else
1769 __kmemleak_do_cleanup();
1770 goto out;
1771 }
1772
Li Zefan8910ae82014-04-03 14:46:29 -07001773 if (!kmemleak_enabled) {
Li Zefanc89da702014-04-03 14:46:27 -07001774 ret = -EBUSY;
1775 goto out;
1776 }
1777
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001778 if (strncmp(buf, "off", 3) == 0)
1779 kmemleak_disable();
1780 else if (strncmp(buf, "stack=on", 8) == 0)
1781 kmemleak_stack_scan = 1;
1782 else if (strncmp(buf, "stack=off", 9) == 0)
1783 kmemleak_stack_scan = 0;
1784 else if (strncmp(buf, "scan=on", 7) == 0)
1785 start_scan_thread();
1786 else if (strncmp(buf, "scan=off", 8) == 0)
1787 stop_scan_thread();
1788 else if (strncmp(buf, "scan=", 5) == 0) {
1789 unsigned long secs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001790
Jingoo Han3dbb95f2013-09-11 14:20:25 -07001791 ret = kstrtoul(buf + 5, 0, &secs);
Catalin Marinasb87324d2009-07-07 10:32:58 +01001792 if (ret < 0)
1793 goto out;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001794 stop_scan_thread();
1795 if (secs) {
1796 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1797 start_scan_thread();
1798 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001799 } else if (strncmp(buf, "scan", 4) == 0)
1800 kmemleak_scan();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001801 else if (strncmp(buf, "dump=", 5) == 0)
1802 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001803 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001804 ret = -EINVAL;
1805
1806out:
1807 mutex_unlock(&scan_mutex);
1808 if (ret < 0)
1809 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001810
1811 /* ignore the rest of the buffer, only one command at a time */
1812 *ppos += size;
1813 return size;
1814}
1815
1816static const struct file_operations kmemleak_fops = {
1817 .owner = THIS_MODULE,
1818 .open = kmemleak_open,
1819 .read = seq_read,
1820 .write = kmemleak_write,
1821 .llseek = seq_lseek,
Li Zefan5f3bf192014-04-03 14:46:28 -07001822 .release = seq_release,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001823};
1824
Li Zefanc89da702014-04-03 14:46:27 -07001825static void __kmemleak_do_cleanup(void)
1826{
1827 struct kmemleak_object *object;
1828
1829 rcu_read_lock();
1830 list_for_each_entry_rcu(object, &object_list, object_list)
1831 delete_object_full(object->pointer);
1832 rcu_read_unlock();
1833}
1834
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001835/*
Catalin Marinas74341702011-09-29 11:50:07 +01001836 * Stop the memory scanning thread and free the kmemleak internal objects if
1837 * no previous scan thread (otherwise, kmemleak may still have some useful
1838 * information on memory leaks).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001839 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001840static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001841{
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001842 stop_scan_thread();
1843
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001844 /*
1845 * Once the scan thread has stopped, it is safe to no longer track
1846 * object freeing. Ordering of the scan thread stopping and the memory
1847 * accesses below is guaranteed by the kthread_stop() function.
1848 */
1849 kmemleak_free_enabled = 0;
1850
Li Zefanc89da702014-04-03 14:46:27 -07001851 if (!kmemleak_found_leaks)
1852 __kmemleak_do_cleanup();
1853 else
Joe Perches756a0252016-03-17 14:19:47 -07001854 pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001855}
1856
Catalin Marinas179a8102009-09-07 10:14:42 +01001857static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001858
1859/*
1860 * Disable kmemleak. No memory allocation/freeing will be traced once this
1861 * function is called. Disabling kmemleak is an irreversible operation.
1862 */
1863static void kmemleak_disable(void)
1864{
1865 /* atomically check whether it was already invoked */
Li Zefan8910ae82014-04-03 14:46:29 -07001866 if (cmpxchg(&kmemleak_error, 0, 1))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001867 return;
1868
1869 /* stop any memory operation tracing */
Li Zefan8910ae82014-04-03 14:46:29 -07001870 kmemleak_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001871
1872 /* check whether it is too early for a kernel thread */
Li Zefan8910ae82014-04-03 14:46:29 -07001873 if (kmemleak_initialized)
Catalin Marinas179a8102009-09-07 10:14:42 +01001874 schedule_work(&cleanup_work);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001875 else
1876 kmemleak_free_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001877
1878 pr_info("Kernel memory leak detector disabled\n");
1879}
1880
1881/*
1882 * Allow boot-time kmemleak disabling (enabled by default).
1883 */
1884static int kmemleak_boot_config(char *str)
1885{
1886 if (!str)
1887 return -EINVAL;
1888 if (strcmp(str, "off") == 0)
1889 kmemleak_disable();
Jason Baronab0155a2010-07-19 11:54:17 +01001890 else if (strcmp(str, "on") == 0)
1891 kmemleak_skip_disable = 1;
1892 else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001893 return -EINVAL;
1894 return 0;
1895}
1896early_param("kmemleak", kmemleak_boot_config);
1897
Catalin Marinas5f790202011-09-28 12:17:03 +01001898static void __init print_log_trace(struct early_log *log)
1899{
1900 struct stack_trace trace;
1901
1902 trace.nr_entries = log->trace_len;
1903 trace.entries = log->trace;
1904
1905 pr_notice("Early log backtrace:\n");
1906 print_stack_trace(&trace, 2);
1907}
1908
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001909/*
Catalin Marinas20301172009-06-17 18:29:04 +01001910 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001911 */
1912void __init kmemleak_init(void)
1913{
1914 int i;
1915 unsigned long flags;
1916
Jason Baronab0155a2010-07-19 11:54:17 +01001917#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
1918 if (!kmemleak_skip_disable) {
Catalin Marinas3551a922014-05-09 15:36:59 -07001919 kmemleak_early_log = 0;
Jason Baronab0155a2010-07-19 11:54:17 +01001920 kmemleak_disable();
1921 return;
1922 }
1923#endif
1924
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001925 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
1926 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
1927
1928 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
1929 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001930
Wang Kai21cd3a62015-09-08 15:03:41 -07001931 if (crt_early_log > ARRAY_SIZE(early_log))
Joe Perches598d8092016-03-17 14:19:44 -07001932 pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
1933 crt_early_log);
Catalin Marinasb6693002011-09-28 17:22:56 +01001934
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001935 /* the kernel is still in UP mode, so disabling the IRQs is enough */
1936 local_irq_save(flags);
Catalin Marinas3551a922014-05-09 15:36:59 -07001937 kmemleak_early_log = 0;
Li Zefan8910ae82014-04-03 14:46:29 -07001938 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +01001939 local_irq_restore(flags);
1940 return;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001941 } else {
Li Zefan8910ae82014-04-03 14:46:29 -07001942 kmemleak_enabled = 1;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001943 kmemleak_free_enabled = 1;
1944 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001945 local_irq_restore(flags);
1946
1947 /*
1948 * This is the point where tracking allocations is safe. Automatic
1949 * scanning is started during the late initcall. Add the early logged
1950 * callbacks to the kmemleak infrastructure.
1951 */
1952 for (i = 0; i < crt_early_log; i++) {
1953 struct early_log *log = &early_log[i];
1954
1955 switch (log->op_type) {
1956 case KMEMLEAK_ALLOC:
Catalin Marinasfd678962009-08-27 14:29:17 +01001957 early_alloc(log);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001958 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001959 case KMEMLEAK_ALLOC_PERCPU:
1960 early_alloc_percpu(log);
1961 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001962 case KMEMLEAK_FREE:
1963 kmemleak_free(log->ptr);
1964 break;
Catalin Marinas53238a62009-07-07 10:33:00 +01001965 case KMEMLEAK_FREE_PART:
1966 kmemleak_free_part(log->ptr, log->size);
1967 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001968 case KMEMLEAK_FREE_PERCPU:
1969 kmemleak_free_percpu(log->ptr);
1970 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001971 case KMEMLEAK_NOT_LEAK:
1972 kmemleak_not_leak(log->ptr);
1973 break;
1974 case KMEMLEAK_IGNORE:
1975 kmemleak_ignore(log->ptr);
1976 break;
1977 case KMEMLEAK_SCAN_AREA:
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001978 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001979 break;
1980 case KMEMLEAK_NO_SCAN:
1981 kmemleak_no_scan(log->ptr);
1982 break;
1983 default:
Catalin Marinas5f790202011-09-28 12:17:03 +01001984 kmemleak_warn("Unknown early log operation: %d\n",
1985 log->op_type);
1986 }
1987
Li Zefan8910ae82014-04-03 14:46:29 -07001988 if (kmemleak_warning) {
Catalin Marinas5f790202011-09-28 12:17:03 +01001989 print_log_trace(log);
Li Zefan8910ae82014-04-03 14:46:29 -07001990 kmemleak_warning = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001991 }
1992 }
1993}
1994
1995/*
1996 * Late initialization function.
1997 */
1998static int __init kmemleak_late_init(void)
1999{
2000 struct dentry *dentry;
2001
Li Zefan8910ae82014-04-03 14:46:29 -07002002 kmemleak_initialized = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002003
Li Zefan8910ae82014-04-03 14:46:29 -07002004 if (kmemleak_error) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002005 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002006 * Some error occurred and kmemleak was disabled. There is a
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002007 * small chance that kmemleak_disable() was called immediately
2008 * after setting kmemleak_initialized and we may end up with
2009 * two clean-up threads but serialized by scan_mutex.
2010 */
Catalin Marinas179a8102009-09-07 10:14:42 +01002011 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002012 return -ENOMEM;
2013 }
2014
2015 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
2016 &kmemleak_fops);
2017 if (!dentry)
Joe Perches598d8092016-03-17 14:19:44 -07002018 pr_warn("Failed to create the debugfs kmemleak file\n");
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002019 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002020 start_scan_thread();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002021 mutex_unlock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002022
2023 pr_info("Kernel memory leak detector initialized\n");
2024
2025 return 0;
2026}
2027late_initcall(kmemleak_late_init);