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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;
Catalin Marinasf66abf02017-07-06 15:40:16 -0700153 unsigned int flags; /* object status flags */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100154 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;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700162 /* pass surplus references to this pointer */
163 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100164 /* minimum number of a pointers found before it is considered leak */
165 int min_count;
166 /* the total number of pointers found pointing to this object */
167 int count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000168 /* checksum for detecting modified objects */
169 u32 checksum;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100170 /* memory ranges to be scanned inside an object (empty for all) */
171 struct hlist_head area_list;
172 unsigned long trace[MAX_TRACE];
173 unsigned int trace_len;
174 unsigned long jiffies; /* creation timestamp */
175 pid_t pid; /* pid of the current task */
176 char comm[TASK_COMM_LEN]; /* executable name */
177};
178
179/* flag representing the memory block allocation status */
180#define OBJECT_ALLOCATED (1 << 0)
181/* flag set after the first reporting of an unreference object */
182#define OBJECT_REPORTED (1 << 1)
183/* flag set to not scan the object */
184#define OBJECT_NO_SCAN (1 << 2)
185
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100186/* number of bytes to print per line; must be 16 or 32 */
187#define HEX_ROW_SIZE 16
188/* number of bytes to print at a time (1, 2, 4, 8) */
189#define HEX_GROUP_SIZE 1
190/* include ASCII after the hex output */
191#define HEX_ASCII 1
192/* max number of lines to be printed */
193#define HEX_MAX_LINES 2
194
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100195/* the list of all allocated objects */
196static LIST_HEAD(object_list);
197/* the list of gray-colored objects (see color_gray comment below) */
198static LIST_HEAD(gray_list);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700199/* search tree for object boundaries */
200static struct rb_root object_tree_root = RB_ROOT;
201/* rw_lock protecting the access to object_list and object_tree_root */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100202static DEFINE_RWLOCK(kmemleak_lock);
203
204/* allocation caches for kmemleak internal data */
205static struct kmem_cache *object_cache;
206static struct kmem_cache *scan_area_cache;
207
208/* set if tracing memory operations is enabled */
Li Zefan8910ae82014-04-03 14:46:29 -0700209static int kmemleak_enabled;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700210/* same as above but only for the kmemleak_free() callback */
211static int kmemleak_free_enabled;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100212/* set in the late_initcall if there were no errors */
Li Zefan8910ae82014-04-03 14:46:29 -0700213static int kmemleak_initialized;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100214/* enables or disables early logging of the memory operations */
Li Zefan8910ae82014-04-03 14:46:29 -0700215static int kmemleak_early_log = 1;
Catalin Marinas5f790202011-09-28 12:17:03 +0100216/* set if a kmemleak warning was issued */
Li Zefan8910ae82014-04-03 14:46:29 -0700217static int kmemleak_warning;
Catalin Marinas5f790202011-09-28 12:17:03 +0100218/* set if a fatal kmemleak error has occurred */
Li Zefan8910ae82014-04-03 14:46:29 -0700219static int kmemleak_error;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100220
221/* minimum and maximum address that may be valid pointers */
222static unsigned long min_addr = ULONG_MAX;
223static unsigned long max_addr;
224
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100225static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100226/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100227static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100228static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100229/* delay between automatic memory scannings */
230static signed long jiffies_scan_wait;
231/* enables or disables the task stacks scanning */
Catalin Marinase0a2a162009-06-26 17:38:25 +0100232static int kmemleak_stack_scan = 1;
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100233/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100234static DEFINE_MUTEX(scan_mutex);
Jason Baronab0155a2010-07-19 11:54:17 +0100235/* setting kmemleak=on, will set this var, skipping the disable */
236static int kmemleak_skip_disable;
Li Zefandc9b3f42014-04-03 14:46:26 -0700237/* If there are leaks that can be reported */
238static bool kmemleak_found_leaks;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100239
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100240/*
Catalin Marinas20301172009-06-17 18:29:04 +0100241 * Early object allocation/freeing logging. Kmemleak is initialized after the
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100242 * kernel allocator. However, both the kernel allocator and kmemleak may
Catalin Marinas20301172009-06-17 18:29:04 +0100243 * allocate memory blocks which need to be tracked. Kmemleak defines an
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100244 * arbitrary buffer to hold the allocation/freeing information before it is
245 * fully initialized.
246 */
247
248/* kmemleak operation type for early logging */
249enum {
250 KMEMLEAK_ALLOC,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100251 KMEMLEAK_ALLOC_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100252 KMEMLEAK_FREE,
Catalin Marinas53238a62009-07-07 10:33:00 +0100253 KMEMLEAK_FREE_PART,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100254 KMEMLEAK_FREE_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100255 KMEMLEAK_NOT_LEAK,
256 KMEMLEAK_IGNORE,
257 KMEMLEAK_SCAN_AREA,
Catalin Marinas94f4a162017-07-06 15:40:22 -0700258 KMEMLEAK_NO_SCAN,
259 KMEMLEAK_SET_EXCESS_REF
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100260};
261
262/*
263 * Structure holding the information passed to kmemleak callbacks during the
264 * early logging.
265 */
266struct early_log {
267 int op_type; /* kmemleak operation type */
Catalin Marinasf66abf02017-07-06 15:40:16 -0700268 int min_count; /* minimum reference count */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100269 const void *ptr; /* allocated/freed memory block */
Catalin Marinas94f4a162017-07-06 15:40:22 -0700270 union {
271 size_t size; /* memory block size */
272 unsigned long excess_ref; /* surplus reference passing */
273 };
Catalin Marinasfd678962009-08-27 14:29:17 +0100274 unsigned long trace[MAX_TRACE]; /* stack trace */
275 unsigned int trace_len; /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100276};
277
278/* early logging buffer and current position */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100279static struct early_log
280 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
281static int crt_early_log __initdata;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100282
283static void kmemleak_disable(void);
284
285/*
286 * Print a warning and dump the stack trace.
287 */
Catalin Marinas5f790202011-09-28 12:17:03 +0100288#define kmemleak_warn(x...) do { \
Joe Perches598d8092016-03-17 14:19:44 -0700289 pr_warn(x); \
Catalin Marinas5f790202011-09-28 12:17:03 +0100290 dump_stack(); \
Li Zefan8910ae82014-04-03 14:46:29 -0700291 kmemleak_warning = 1; \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100292} while (0)
293
294/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300295 * Macro invoked when a serious kmemleak condition occurred and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100296 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100297 * tracing no longer available.
298 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100299#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100300 kmemleak_warn(x); \
301 kmemleak_disable(); \
302} while (0)
303
304/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100305 * Printing of the objects hex dump to the seq file. The number of lines to be
306 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
307 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
308 * with the object->lock held.
309 */
310static void hex_dump_object(struct seq_file *seq,
311 struct kmemleak_object *object)
312{
313 const u8 *ptr = (const u8 *)object->pointer;
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700314 size_t len;
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100315
316 /* limit the number of lines to HEX_MAX_LINES */
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700317 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100318
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700319 seq_printf(seq, " hex dump (first %zu bytes):\n", len);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700320 kasan_disable_current();
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700321 seq_hex_dump(seq, " ", DUMP_PREFIX_NONE, HEX_ROW_SIZE,
322 HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700323 kasan_enable_current();
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100324}
325
326/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100327 * Object colors, encoded with count and min_count:
328 * - white - orphan object, not enough references to it (count < min_count)
329 * - gray - not orphan, not marked as false positive (min_count == 0) or
330 * sufficient references to it (count >= min_count)
331 * - black - ignore, it doesn't contain references (e.g. text section)
332 * (min_count == -1). No function defined for this color.
333 * Newly created objects don't have any color assigned (object->count == -1)
334 * before the next memory scan when they become white.
335 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100336static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100337{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700338 return object->count != KMEMLEAK_BLACK &&
339 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100340}
341
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100342static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100343{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700344 return object->min_count != KMEMLEAK_BLACK &&
345 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100346}
347
348/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100349 * Objects are considered unreferenced only if their color is white, they have
350 * not be deleted and have a minimum age to avoid false positives caused by
351 * pointers temporarily stored in CPU registers.
352 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100353static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100354{
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000355 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100356 time_before_eq(object->jiffies + jiffies_min_age,
357 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100358}
359
360/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100361 * Printing of the unreferenced objects information to the seq file. The
362 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100363 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100364static void print_unreferenced(struct seq_file *seq,
365 struct kmemleak_object *object)
366{
367 int i;
Catalin Marinasfefdd332009-10-28 13:33:12 +0000368 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100369
Catalin Marinasbab4a342009-06-26 17:38:26 +0100370 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
371 object->pointer, object->size);
Catalin Marinasfefdd332009-10-28 13:33:12 +0000372 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
373 object->comm, object->pid, object->jiffies,
374 msecs_age / 1000, msecs_age % 1000);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100375 hex_dump_object(seq, object);
Catalin Marinasbab4a342009-06-26 17:38:26 +0100376 seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100377
378 for (i = 0; i < object->trace_len; i++) {
379 void *ptr = (void *)object->trace[i];
Catalin Marinasbab4a342009-06-26 17:38:26 +0100380 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100381 }
382}
383
384/*
385 * Print the kmemleak_object information. This function is used mainly for
386 * debugging special cases when kmemleak operations. It must be called with
387 * the object->lock held.
388 */
389static void dump_object_info(struct kmemleak_object *object)
390{
391 struct stack_trace trace;
392
393 trace.nr_entries = object->trace_len;
394 trace.entries = object->trace;
395
Joe Perchesae281062009-06-23 14:40:26 +0100396 pr_notice("Object 0x%08lx (size %zu):\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700397 object->pointer, object->size);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100398 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
399 object->comm, object->pid, object->jiffies);
400 pr_notice(" min_count = %d\n", object->min_count);
401 pr_notice(" count = %d\n", object->count);
Catalin Marinasf66abf02017-07-06 15:40:16 -0700402 pr_notice(" flags = 0x%x\n", object->flags);
Jianpeng Maaae0ad72014-06-06 14:38:16 -0700403 pr_notice(" checksum = %u\n", object->checksum);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100404 pr_notice(" backtrace:\n");
405 print_stack_trace(&trace, 4);
406}
407
408/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700409 * Look-up a memory block metadata (kmemleak_object) in the object search
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100410 * tree based on a pointer value. If alias is 0, only values pointing to the
411 * beginning of the memory block are allowed. The kmemleak_lock must be held
412 * when calling this function.
413 */
414static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
415{
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700416 struct rb_node *rb = object_tree_root.rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100417
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700418 while (rb) {
419 struct kmemleak_object *object =
420 rb_entry(rb, struct kmemleak_object, rb_node);
421 if (ptr < object->pointer)
422 rb = object->rb_node.rb_left;
423 else if (object->pointer + object->size <= ptr)
424 rb = object->rb_node.rb_right;
425 else if (object->pointer == ptr || alias)
426 return object;
427 else {
Catalin Marinas5f790202011-09-28 12:17:03 +0100428 kmemleak_warn("Found object by alias at 0x%08lx\n",
429 ptr);
Catalin Marinasa7686a42010-07-19 11:54:16 +0100430 dump_object_info(object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700431 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100432 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700433 }
434 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100435}
436
437/*
438 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
439 * that once an object's use_count reached 0, the RCU freeing was already
440 * registered and the object should no longer be used. This function must be
441 * called under the protection of rcu_read_lock().
442 */
443static int get_object(struct kmemleak_object *object)
444{
445 return atomic_inc_not_zero(&object->use_count);
446}
447
448/*
449 * RCU callback to free a kmemleak_object.
450 */
451static void free_object_rcu(struct rcu_head *rcu)
452{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800453 struct hlist_node *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100454 struct kmemleak_scan_area *area;
455 struct kmemleak_object *object =
456 container_of(rcu, struct kmemleak_object, rcu);
457
458 /*
459 * Once use_count is 0 (guaranteed by put_object), there is no other
460 * code accessing this object, hence no need for locking.
461 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800462 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
463 hlist_del(&area->node);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100464 kmem_cache_free(scan_area_cache, area);
465 }
466 kmem_cache_free(object_cache, object);
467}
468
469/*
470 * Decrement the object use_count. Once the count is 0, free the object using
471 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
472 * delete_object() path, the delayed RCU freeing ensures that there is no
473 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
474 * is also possible.
475 */
476static void put_object(struct kmemleak_object *object)
477{
478 if (!atomic_dec_and_test(&object->use_count))
479 return;
480
481 /* should only get here after delete_object was called */
482 WARN_ON(object->flags & OBJECT_ALLOCATED);
483
484 call_rcu(&object->rcu, free_object_rcu);
485}
486
487/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700488 * Look up an object in the object search tree and increase its use_count.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100489 */
490static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
491{
492 unsigned long flags;
Alexey Klimov9fbed252015-11-05 18:45:57 -0800493 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100494
495 rcu_read_lock();
496 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -0700497 object = lookup_object(ptr, alias);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100498 read_unlock_irqrestore(&kmemleak_lock, flags);
499
500 /* check whether the object is still available */
501 if (object && !get_object(object))
502 object = NULL;
503 rcu_read_unlock();
504
505 return object;
506}
507
508/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700509 * Look up an object in the object search tree and remove it from both
510 * object_tree_root and object_list. The returned object's use_count should be
511 * at least 1, as initially set by create_object().
512 */
513static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
514{
515 unsigned long flags;
516 struct kmemleak_object *object;
517
518 write_lock_irqsave(&kmemleak_lock, flags);
519 object = lookup_object(ptr, alias);
520 if (object) {
521 rb_erase(&object->rb_node, &object_tree_root);
522 list_del_rcu(&object->object_list);
523 }
524 write_unlock_irqrestore(&kmemleak_lock, flags);
525
526 return object;
527}
528
529/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100530 * Save stack trace to the given array of MAX_TRACE size.
531 */
532static int __save_stack_trace(unsigned long *trace)
533{
534 struct stack_trace stack_trace;
535
536 stack_trace.max_entries = MAX_TRACE;
537 stack_trace.nr_entries = 0;
538 stack_trace.entries = trace;
539 stack_trace.skip = 2;
540 save_stack_trace(&stack_trace);
541
542 return stack_trace.nr_entries;
543}
544
545/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100546 * Create the metadata (struct kmemleak_object) corresponding to an allocated
547 * memory block and add it to the object_list and object_tree_root.
548 */
Catalin Marinasfd678962009-08-27 14:29:17 +0100549static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
550 int min_count, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100551{
552 unsigned long flags;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700553 struct kmemleak_object *object, *parent;
554 struct rb_node **link, *rb_parent;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100555
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000556 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100557 if (!object) {
Joe Perches598d8092016-03-17 14:19:44 -0700558 pr_warn("Cannot allocate a kmemleak_object structure\n");
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000559 kmemleak_disable();
Catalin Marinasfd678962009-08-27 14:29:17 +0100560 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100561 }
562
563 INIT_LIST_HEAD(&object->object_list);
564 INIT_LIST_HEAD(&object->gray_list);
565 INIT_HLIST_HEAD(&object->area_list);
566 spin_lock_init(&object->lock);
567 atomic_set(&object->use_count, 1);
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000568 object->flags = OBJECT_ALLOCATED;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100569 object->pointer = ptr;
570 object->size = size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700571 object->excess_ref = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100572 object->min_count = min_count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000573 object->count = 0; /* white color initially */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100574 object->jiffies = jiffies;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000575 object->checksum = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100576
577 /* task information */
578 if (in_irq()) {
579 object->pid = 0;
580 strncpy(object->comm, "hardirq", sizeof(object->comm));
581 } else if (in_softirq()) {
582 object->pid = 0;
583 strncpy(object->comm, "softirq", sizeof(object->comm));
584 } else {
585 object->pid = current->pid;
586 /*
587 * There is a small chance of a race with set_task_comm(),
588 * however using get_task_comm() here may cause locking
589 * dependency issues with current->alloc_lock. In the worst
590 * case, the command line is not correct.
591 */
592 strncpy(object->comm, current->comm, sizeof(object->comm));
593 }
594
595 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100596 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100597
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100598 write_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100599
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100600 min_addr = min(min_addr, ptr);
601 max_addr = max(max_addr, ptr + size);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700602 link = &object_tree_root.rb_node;
603 rb_parent = NULL;
604 while (*link) {
605 rb_parent = *link;
606 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
607 if (ptr + size <= parent->pointer)
608 link = &parent->rb_node.rb_left;
609 else if (parent->pointer + parent->size <= ptr)
610 link = &parent->rb_node.rb_right;
611 else {
Joe Perches756a0252016-03-17 14:19:47 -0700612 kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700613 ptr);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700614 /*
615 * No need for parent->lock here since "parent" cannot
616 * be freed while the kmemleak_lock is held.
617 */
618 dump_object_info(parent);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700619 kmem_cache_free(object_cache, object);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700620 object = NULL;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700621 goto out;
622 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100623 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700624 rb_link_node(&object->rb_node, rb_parent, link);
625 rb_insert_color(&object->rb_node, &object_tree_root);
626
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100627 list_add_tail_rcu(&object->object_list, &object_list);
628out:
629 write_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinasfd678962009-08-27 14:29:17 +0100630 return object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100631}
632
633/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700634 * Mark the object as not allocated and schedule RCU freeing via put_object().
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100635 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100636static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100637{
638 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100639
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100640 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinase781a9a2015-06-24 16:58:29 -0700641 WARN_ON(atomic_read(&object->use_count) < 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100642
643 /*
644 * Locking here also ensures that the corresponding memory block
645 * cannot be freed when it is being scanned.
646 */
647 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100648 object->flags &= ~OBJECT_ALLOCATED;
649 spin_unlock_irqrestore(&object->lock, flags);
650 put_object(object);
651}
652
653/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100654 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
655 * delete it.
656 */
657static void delete_object_full(unsigned long ptr)
658{
659 struct kmemleak_object *object;
660
Catalin Marinase781a9a2015-06-24 16:58:29 -0700661 object = find_and_remove_object(ptr, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100662 if (!object) {
663#ifdef DEBUG
664 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
665 ptr);
666#endif
667 return;
668 }
669 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100670}
671
672/*
673 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
674 * delete it. If the memory block is partially freed, the function may create
675 * additional metadata for the remaining parts of the block.
676 */
677static void delete_object_part(unsigned long ptr, size_t size)
678{
679 struct kmemleak_object *object;
680 unsigned long start, end;
681
Catalin Marinase781a9a2015-06-24 16:58:29 -0700682 object = find_and_remove_object(ptr, 1);
Catalin Marinas53238a62009-07-07 10:33:00 +0100683 if (!object) {
684#ifdef DEBUG
Joe Perches756a0252016-03-17 14:19:47 -0700685 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
686 ptr, size);
Catalin Marinas53238a62009-07-07 10:33:00 +0100687#endif
688 return;
689 }
Catalin Marinas53238a62009-07-07 10:33:00 +0100690
691 /*
692 * Create one or two objects that may result from the memory block
693 * split. Note that partial freeing is only done by free_bootmem() and
694 * this happens before kmemleak_init() is called. The path below is
695 * only executed during early log recording in kmemleak_init(), so
696 * GFP_KERNEL is enough.
697 */
698 start = object->pointer;
699 end = object->pointer + object->size;
700 if (ptr > start)
701 create_object(start, ptr - start, object->min_count,
702 GFP_KERNEL);
703 if (ptr + size < end)
704 create_object(ptr + size, end - ptr - size, object->min_count,
705 GFP_KERNEL);
706
Catalin Marinase781a9a2015-06-24 16:58:29 -0700707 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100708}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700709
710static void __paint_it(struct kmemleak_object *object, int color)
711{
712 object->min_count = color;
713 if (color == KMEMLEAK_BLACK)
714 object->flags |= OBJECT_NO_SCAN;
715}
716
717static void paint_it(struct kmemleak_object *object, int color)
718{
719 unsigned long flags;
720
721 spin_lock_irqsave(&object->lock, flags);
722 __paint_it(object, color);
723 spin_unlock_irqrestore(&object->lock, flags);
724}
725
726static void paint_ptr(unsigned long ptr, int color)
727{
728 struct kmemleak_object *object;
729
730 object = find_and_get_object(ptr, 0);
731 if (!object) {
Joe Perches756a0252016-03-17 14:19:47 -0700732 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
733 ptr,
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700734 (color == KMEMLEAK_GREY) ? "Grey" :
735 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
736 return;
737 }
738 paint_it(object, color);
739 put_object(object);
740}
741
Catalin Marinas53238a62009-07-07 10:33:00 +0100742/*
Holger Hans Peter Freyther145b64b2010-07-22 19:54:13 +0800743 * Mark an object permanently as gray-colored so that it can no longer be
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100744 * reported as a leak. This is used in general to mark a false positive.
745 */
746static void make_gray_object(unsigned long ptr)
747{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700748 paint_ptr(ptr, KMEMLEAK_GREY);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100749}
750
751/*
752 * Mark the object as black-colored so that it is ignored from scans and
753 * reporting.
754 */
755static void make_black_object(unsigned long ptr)
756{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700757 paint_ptr(ptr, KMEMLEAK_BLACK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100758}
759
760/*
761 * Add a scanning area to the object. If at least one such area is added,
762 * kmemleak will only scan these ranges rather than the whole memory block.
763 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000764static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100765{
766 unsigned long flags;
767 struct kmemleak_object *object;
768 struct kmemleak_scan_area *area;
769
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000770 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100771 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100772 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
773 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100774 return;
775 }
776
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000777 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100778 if (!area) {
Joe Perches598d8092016-03-17 14:19:44 -0700779 pr_warn("Cannot allocate a scan area\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100780 goto out;
781 }
782
783 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas7f88f882013-11-12 15:07:45 -0800784 if (size == SIZE_MAX) {
785 size = object->pointer + object->size - ptr;
786 } else if (ptr + size > object->pointer + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100787 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100788 dump_object_info(object);
789 kmem_cache_free(scan_area_cache, area);
790 goto out_unlock;
791 }
792
793 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000794 area->start = ptr;
795 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100796
797 hlist_add_head(&area->node, &object->area_list);
798out_unlock:
799 spin_unlock_irqrestore(&object->lock, flags);
800out:
801 put_object(object);
802}
803
804/*
Catalin Marinas94f4a162017-07-06 15:40:22 -0700805 * Any surplus references (object already gray) to 'ptr' are passed to
806 * 'excess_ref'. This is used in the vmalloc() case where a pointer to
807 * vm_struct may be used as an alternative reference to the vmalloc'ed object
808 * (see free_thread_stack()).
809 */
810static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
811{
812 unsigned long flags;
813 struct kmemleak_object *object;
814
815 object = find_and_get_object(ptr, 0);
816 if (!object) {
817 kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
818 ptr);
819 return;
820 }
821
822 spin_lock_irqsave(&object->lock, flags);
823 object->excess_ref = excess_ref;
824 spin_unlock_irqrestore(&object->lock, flags);
825 put_object(object);
826}
827
828/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100829 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
830 * pointer. Such object will not be scanned by kmemleak but references to it
831 * are searched.
832 */
833static void object_no_scan(unsigned long ptr)
834{
835 unsigned long flags;
836 struct kmemleak_object *object;
837
838 object = find_and_get_object(ptr, 0);
839 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100840 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100841 return;
842 }
843
844 spin_lock_irqsave(&object->lock, flags);
845 object->flags |= OBJECT_NO_SCAN;
846 spin_unlock_irqrestore(&object->lock, flags);
847 put_object(object);
848}
849
850/*
851 * Log an early kmemleak_* call to the early_log buffer. These calls will be
852 * processed later once kmemleak is fully initialized.
853 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100854static void __init log_early(int op_type, const void *ptr, size_t size,
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000855 int min_count)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100856{
857 unsigned long flags;
858 struct early_log *log;
859
Li Zefan8910ae82014-04-03 14:46:29 -0700860 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +0100861 /* kmemleak stopped recording, just count the requests */
862 crt_early_log++;
863 return;
864 }
865
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100866 if (crt_early_log >= ARRAY_SIZE(early_log)) {
Wang Kai21cd3a62015-09-08 15:03:41 -0700867 crt_early_log++;
Catalin Marinasa9d90582009-06-25 10:16:11 +0100868 kmemleak_disable();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100869 return;
870 }
871
872 /*
873 * There is no need for locking since the kernel is still in UP mode
874 * at this stage. Disabling the IRQs is enough.
875 */
876 local_irq_save(flags);
877 log = &early_log[crt_early_log];
878 log->op_type = op_type;
879 log->ptr = ptr;
880 log->size = size;
881 log->min_count = min_count;
Catalin Marinas5f790202011-09-28 12:17:03 +0100882 log->trace_len = __save_stack_trace(log->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100883 crt_early_log++;
884 local_irq_restore(flags);
885}
886
887/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100888 * Log an early allocated block and populate the stack trace.
889 */
890static void early_alloc(struct early_log *log)
891{
892 struct kmemleak_object *object;
893 unsigned long flags;
894 int i;
895
Li Zefan8910ae82014-04-03 14:46:29 -0700896 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
Catalin Marinasfd678962009-08-27 14:29:17 +0100897 return;
898
899 /*
900 * RCU locking needed to ensure object is not freed via put_object().
901 */
902 rcu_read_lock();
903 object = create_object((unsigned long)log->ptr, log->size,
Tetsuo Handac1bcd6b2009-10-09 10:39:24 +0100904 log->min_count, GFP_ATOMIC);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100905 if (!object)
906 goto out;
Catalin Marinasfd678962009-08-27 14:29:17 +0100907 spin_lock_irqsave(&object->lock, flags);
908 for (i = 0; i < log->trace_len; i++)
909 object->trace[i] = log->trace[i];
910 object->trace_len = log->trace_len;
911 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100912out:
Catalin Marinasfd678962009-08-27 14:29:17 +0100913 rcu_read_unlock();
914}
915
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100916/*
917 * Log an early allocated block and populate the stack trace.
918 */
919static void early_alloc_percpu(struct early_log *log)
920{
921 unsigned int cpu;
922 const void __percpu *ptr = log->ptr;
923
924 for_each_possible_cpu(cpu) {
925 log->ptr = per_cpu_ptr(ptr, cpu);
926 early_alloc(log);
927 }
928}
929
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100930/**
931 * kmemleak_alloc - register a newly allocated object
932 * @ptr: pointer to beginning of the object
933 * @size: size of the object
934 * @min_count: minimum number of references to this object. If during memory
935 * scanning a number of references less than @min_count is found,
936 * the object is reported as a memory leak. If @min_count is 0,
937 * the object is never reported as a leak. If @min_count is -1,
938 * the object is ignored (not scanned and not reported as a leak)
939 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
940 *
941 * This function is called from the kernel allocators when a new object
Catalin Marinas94f4a162017-07-06 15:40:22 -0700942 * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100943 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100944void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
945 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100946{
947 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
948
Li Zefan8910ae82014-04-03 14:46:29 -0700949 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100950 create_object((unsigned long)ptr, size, min_count, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700951 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000952 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100953}
954EXPORT_SYMBOL_GPL(kmemleak_alloc);
955
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100956/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100957 * kmemleak_alloc_percpu - register a newly allocated __percpu object
958 * @ptr: __percpu pointer to beginning of the object
959 * @size: size of the object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700960 * @gfp: flags used for kmemleak internal memory allocations
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100961 *
962 * This function is called from the kernel percpu allocator when a new object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700963 * (memory block) is allocated (alloc_percpu).
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100964 */
Larry Finger8a8c35f2015-06-24 16:58:51 -0700965void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
966 gfp_t gfp)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100967{
968 unsigned int cpu;
969
970 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
971
972 /*
973 * Percpu allocations are only scanned and not reported as leaks
974 * (min_count is set to 0).
975 */
Li Zefan8910ae82014-04-03 14:46:29 -0700976 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100977 for_each_possible_cpu(cpu)
978 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
Larry Finger8a8c35f2015-06-24 16:58:51 -0700979 size, 0, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700980 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100981 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
982}
983EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
984
985/**
Catalin Marinas94f4a162017-07-06 15:40:22 -0700986 * kmemleak_vmalloc - register a newly vmalloc'ed object
987 * @area: pointer to vm_struct
988 * @size: size of the object
989 * @gfp: __vmalloc() flags used for kmemleak internal memory allocations
990 *
991 * This function is called from the vmalloc() kernel allocator when a new
992 * object (memory block) is allocated.
993 */
994void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp)
995{
996 pr_debug("%s(0x%p, %zu)\n", __func__, area, size);
997
998 /*
999 * A min_count = 2 is needed because vm_struct contains a reference to
1000 * the virtual address of the vmalloc'ed block.
1001 */
1002 if (kmemleak_enabled) {
1003 create_object((unsigned long)area->addr, size, 2, gfp);
1004 object_set_excess_ref((unsigned long)area,
1005 (unsigned long)area->addr);
1006 } else if (kmemleak_early_log) {
1007 log_early(KMEMLEAK_ALLOC, area->addr, size, 2);
1008 /* reusing early_log.size for storing area->addr */
1009 log_early(KMEMLEAK_SET_EXCESS_REF,
1010 area, (unsigned long)area->addr, 0);
1011 }
1012}
1013EXPORT_SYMBOL_GPL(kmemleak_vmalloc);
1014
1015/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001016 * kmemleak_free - unregister a previously registered object
1017 * @ptr: pointer to beginning of the object
1018 *
1019 * This function is called from the kernel allocators when an object (memory
1020 * block) is freed (kmem_cache_free, kfree, vfree etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001021 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001022void __ref kmemleak_free(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001023{
1024 pr_debug("%s(0x%p)\n", __func__, ptr);
1025
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001026 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +01001027 delete_object_full((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001028 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001029 log_early(KMEMLEAK_FREE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001030}
1031EXPORT_SYMBOL_GPL(kmemleak_free);
1032
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001033/**
1034 * kmemleak_free_part - partially unregister a previously registered object
1035 * @ptr: pointer to the beginning or inside the object. This also
1036 * represents the start of the range to be freed
1037 * @size: size to be unregistered
1038 *
1039 * This function is called when only a part of a memory block is freed
1040 * (usually from the bootmem allocator).
Catalin Marinas53238a62009-07-07 10:33:00 +01001041 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001042void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +01001043{
1044 pr_debug("%s(0x%p)\n", __func__, ptr);
1045
Li Zefan8910ae82014-04-03 14:46:29 -07001046 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +01001047 delete_object_part((unsigned long)ptr, size);
Li Zefan8910ae82014-04-03 14:46:29 -07001048 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001049 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +01001050}
1051EXPORT_SYMBOL_GPL(kmemleak_free_part);
1052
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001053/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001054 * kmemleak_free_percpu - unregister a previously registered __percpu object
1055 * @ptr: __percpu pointer to beginning of the object
1056 *
1057 * This function is called from the kernel percpu allocator when an object
1058 * (memory block) is freed (free_percpu).
1059 */
1060void __ref kmemleak_free_percpu(const void __percpu *ptr)
1061{
1062 unsigned int cpu;
1063
1064 pr_debug("%s(0x%p)\n", __func__, ptr);
1065
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001066 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001067 for_each_possible_cpu(cpu)
1068 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1069 cpu));
Li Zefan8910ae82014-04-03 14:46:29 -07001070 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001071 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1072}
1073EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1074
1075/**
Catalin Marinasffe2c742014-06-06 14:38:17 -07001076 * kmemleak_update_trace - update object allocation stack trace
1077 * @ptr: pointer to beginning of the object
1078 *
1079 * Override the object allocation stack trace for cases where the actual
1080 * allocation place is not always useful.
1081 */
1082void __ref kmemleak_update_trace(const void *ptr)
1083{
1084 struct kmemleak_object *object;
1085 unsigned long flags;
1086
1087 pr_debug("%s(0x%p)\n", __func__, ptr);
1088
1089 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1090 return;
1091
1092 object = find_and_get_object((unsigned long)ptr, 1);
1093 if (!object) {
1094#ifdef DEBUG
1095 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1096 ptr);
1097#endif
1098 return;
1099 }
1100
1101 spin_lock_irqsave(&object->lock, flags);
1102 object->trace_len = __save_stack_trace(object->trace);
1103 spin_unlock_irqrestore(&object->lock, flags);
1104
1105 put_object(object);
1106}
1107EXPORT_SYMBOL(kmemleak_update_trace);
1108
1109/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001110 * kmemleak_not_leak - mark an allocated object as false positive
1111 * @ptr: pointer to beginning of the object
1112 *
1113 * Calling this function on an object will cause the memory block to no longer
1114 * be reported as leak and always be scanned.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001115 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001116void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001117{
1118 pr_debug("%s(0x%p)\n", __func__, ptr);
1119
Li Zefan8910ae82014-04-03 14:46:29 -07001120 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001121 make_gray_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001122 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001123 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001124}
1125EXPORT_SYMBOL(kmemleak_not_leak);
1126
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001127/**
1128 * kmemleak_ignore - ignore an allocated object
1129 * @ptr: pointer to beginning of the object
1130 *
1131 * Calling this function on an object will cause the memory block to be
1132 * ignored (not scanned and not reported as a leak). This is usually done when
1133 * it is known that the corresponding block is not a leak and does not contain
1134 * any references to other allocated memory blocks.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001135 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001136void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001137{
1138 pr_debug("%s(0x%p)\n", __func__, ptr);
1139
Li Zefan8910ae82014-04-03 14:46:29 -07001140 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001141 make_black_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001142 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001143 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001144}
1145EXPORT_SYMBOL(kmemleak_ignore);
1146
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001147/**
1148 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1149 * @ptr: pointer to beginning or inside the object. This also
1150 * represents the start of the scan area
1151 * @size: size of the scan area
1152 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1153 *
1154 * This function is used when it is known that only certain parts of an object
1155 * contain references to other objects. Kmemleak will only scan these areas
1156 * reducing the number false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001157 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001158void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001159{
1160 pr_debug("%s(0x%p)\n", __func__, ptr);
1161
Li Zefan8910ae82014-04-03 14:46:29 -07001162 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001163 add_scan_area((unsigned long)ptr, size, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -07001164 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001165 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001166}
1167EXPORT_SYMBOL(kmemleak_scan_area);
1168
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001169/**
1170 * kmemleak_no_scan - do not scan an allocated object
1171 * @ptr: pointer to beginning of the object
1172 *
1173 * This function notifies kmemleak not to scan the given memory block. Useful
1174 * in situations where it is known that the given object does not contain any
1175 * references to other objects. Kmemleak will not scan such objects reducing
1176 * the number of false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001177 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001178void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001179{
1180 pr_debug("%s(0x%p)\n", __func__, ptr);
1181
Li Zefan8910ae82014-04-03 14:46:29 -07001182 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001183 object_no_scan((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001184 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001185 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001186}
1187EXPORT_SYMBOL(kmemleak_no_scan);
1188
Catalin Marinas9099dae2016-10-11 13:55:11 -07001189/**
1190 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1191 * address argument
1192 */
1193void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
1194 gfp_t gfp)
1195{
1196 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1197 kmemleak_alloc(__va(phys), size, min_count, gfp);
1198}
1199EXPORT_SYMBOL(kmemleak_alloc_phys);
1200
1201/**
1202 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1203 * physical address argument
1204 */
1205void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1206{
1207 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1208 kmemleak_free_part(__va(phys), size);
1209}
1210EXPORT_SYMBOL(kmemleak_free_part_phys);
1211
1212/**
1213 * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
1214 * address argument
1215 */
1216void __ref kmemleak_not_leak_phys(phys_addr_t phys)
1217{
1218 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1219 kmemleak_not_leak(__va(phys));
1220}
1221EXPORT_SYMBOL(kmemleak_not_leak_phys);
1222
1223/**
1224 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1225 * address argument
1226 */
1227void __ref kmemleak_ignore_phys(phys_addr_t phys)
1228{
1229 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1230 kmemleak_ignore(__va(phys));
1231}
1232EXPORT_SYMBOL(kmemleak_ignore_phys);
1233
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001234/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001235 * Update an object's checksum and return true if it was modified.
1236 */
1237static bool update_checksum(struct kmemleak_object *object)
1238{
1239 u32 old_csum = object->checksum;
1240
1241 if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
1242 return false;
1243
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001244 kasan_disable_current();
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001245 object->checksum = crc32(0, (void *)object->pointer, object->size);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001246 kasan_enable_current();
1247
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001248 return object->checksum != old_csum;
1249}
1250
1251/*
Catalin Marinas04f70d12017-07-06 15:40:19 -07001252 * Update an object's references. object->lock must be held by the caller.
1253 */
1254static void update_refs(struct kmemleak_object *object)
1255{
1256 if (!color_white(object)) {
1257 /* non-orphan, ignored or new */
1258 return;
1259 }
1260
1261 /*
1262 * Increase the object's reference count (number of pointers to the
1263 * memory block). If this count reaches the required minimum, the
1264 * object's color will become gray and it will be added to the
1265 * gray_list.
1266 */
1267 object->count++;
1268 if (color_gray(object)) {
1269 /* put_object() called when removing from gray_list */
1270 WARN_ON(!get_object(object));
1271 list_add_tail(&object->gray_list, &gray_list);
1272 }
1273}
1274
1275/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001276 * Memory scanning is a long process and it needs to be interruptable. This
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001277 * function checks whether such interrupt condition occurred.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001278 */
1279static int scan_should_stop(void)
1280{
Li Zefan8910ae82014-04-03 14:46:29 -07001281 if (!kmemleak_enabled)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001282 return 1;
1283
1284 /*
1285 * This function may be called from either process or kthread context,
1286 * hence the need to check for both stop conditions.
1287 */
1288 if (current->mm)
1289 return signal_pending(current);
1290 else
1291 return kthread_should_stop();
1292
1293 return 0;
1294}
1295
1296/*
1297 * Scan a memory block (exclusive range) for valid pointers and add those
1298 * found to the gray list.
1299 */
1300static void scan_block(void *_start, void *_end,
Catalin Marinas93ada572015-06-24 16:58:37 -07001301 struct kmemleak_object *scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001302{
1303 unsigned long *ptr;
1304 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1305 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
Catalin Marinas93ada572015-06-24 16:58:37 -07001306 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001307
Catalin Marinas93ada572015-06-24 16:58:37 -07001308 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001309 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001310 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +01001311 unsigned long pointer;
Catalin Marinas94f4a162017-07-06 15:40:22 -07001312 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001313
1314 if (scan_should_stop())
1315 break;
1316
Pekka Enberg8e019362009-08-27 14:50:00 +01001317 /* don't scan uninitialized memory */
1318 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
1319 BYTES_PER_POINTER))
1320 continue;
1321
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001322 kasan_disable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001323 pointer = *ptr;
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001324 kasan_enable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001325
Catalin Marinas93ada572015-06-24 16:58:37 -07001326 if (pointer < min_addr || pointer >= max_addr)
1327 continue;
1328
1329 /*
1330 * No need for get_object() here since we hold kmemleak_lock.
1331 * object->use_count cannot be dropped to 0 while the object
1332 * is still present in object_tree_root and object_list
1333 * (with updates protected by kmemleak_lock).
1334 */
1335 object = lookup_object(pointer, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001336 if (!object)
1337 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001338 if (object == scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001339 /* self referenced, ignore */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001340 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001341
1342 /*
1343 * Avoid the lockdep recursive warning on object->lock being
1344 * previously acquired in scan_object(). These locks are
1345 * enclosed by scan_mutex.
1346 */
Catalin Marinas93ada572015-06-24 16:58:37 -07001347 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001348 /* only pass surplus references (object already gray) */
1349 if (color_gray(object)) {
1350 excess_ref = object->excess_ref;
1351 /* no need for update_refs() if object already gray */
1352 } else {
1353 excess_ref = 0;
1354 update_refs(object);
1355 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001356 spin_unlock(&object->lock);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001357
1358 if (excess_ref) {
1359 object = lookup_object(excess_ref, 0);
1360 if (!object)
1361 continue;
1362 if (object == scanned)
1363 /* circular reference, ignore */
1364 continue;
1365 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
1366 update_refs(object);
1367 spin_unlock(&object->lock);
1368 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001369 }
1370 read_unlock_irqrestore(&kmemleak_lock, flags);
1371}
Catalin Marinas0587da42009-10-28 13:33:11 +00001372
Catalin Marinas93ada572015-06-24 16:58:37 -07001373/*
1374 * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1375 */
1376static void scan_large_block(void *start, void *end)
1377{
1378 void *next;
1379
1380 while (start < end) {
1381 next = min(start + MAX_SCAN_SIZE, end);
1382 scan_block(start, next, NULL);
1383 start = next;
1384 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001385 }
1386}
1387
1388/*
1389 * Scan a memory block corresponding to a kmemleak_object. A condition is
1390 * that object->use_count >= 1.
1391 */
1392static void scan_object(struct kmemleak_object *object)
1393{
1394 struct kmemleak_scan_area *area;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001395 unsigned long flags;
1396
1397 /*
Uwe Kleine-König21ae2952009-10-07 15:21:09 +02001398 * Once the object->lock is acquired, the corresponding memory block
1399 * cannot be freed (the same lock is acquired in delete_object).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001400 */
1401 spin_lock_irqsave(&object->lock, flags);
1402 if (object->flags & OBJECT_NO_SCAN)
1403 goto out;
1404 if (!(object->flags & OBJECT_ALLOCATED))
1405 /* already freed object */
1406 goto out;
Catalin Marinasaf986032009-08-27 14:29:12 +01001407 if (hlist_empty(&object->area_list)) {
1408 void *start = (void *)object->pointer;
1409 void *end = (void *)(object->pointer + object->size);
Catalin Marinas93ada572015-06-24 16:58:37 -07001410 void *next;
Catalin Marinasaf986032009-08-27 14:29:12 +01001411
Catalin Marinas93ada572015-06-24 16:58:37 -07001412 do {
1413 next = min(start + MAX_SCAN_SIZE, end);
1414 scan_block(start, next, object);
1415
1416 start = next;
1417 if (start >= end)
1418 break;
Catalin Marinasaf986032009-08-27 14:29:12 +01001419
1420 spin_unlock_irqrestore(&object->lock, flags);
1421 cond_resched();
1422 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -07001423 } while (object->flags & OBJECT_ALLOCATED);
Catalin Marinasaf986032009-08-27 14:29:12 +01001424 } else
Sasha Levinb67bfe02013-02-27 17:06:00 -08001425 hlist_for_each_entry(area, &object->area_list, node)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001426 scan_block((void *)area->start,
1427 (void *)(area->start + area->size),
Catalin Marinas93ada572015-06-24 16:58:37 -07001428 object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001429out:
1430 spin_unlock_irqrestore(&object->lock, flags);
1431}
1432
1433/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001434 * Scan the objects already referenced (gray objects). More objects will be
1435 * referenced and, if there are no memory leaks, all the objects are scanned.
1436 */
1437static void scan_gray_list(void)
1438{
1439 struct kmemleak_object *object, *tmp;
1440
1441 /*
1442 * The list traversal is safe for both tail additions and removals
1443 * from inside the loop. The kmemleak objects cannot be freed from
1444 * outside the loop because their use_count was incremented.
1445 */
1446 object = list_entry(gray_list.next, typeof(*object), gray_list);
1447 while (&object->gray_list != &gray_list) {
1448 cond_resched();
1449
1450 /* may add new objects to the list */
1451 if (!scan_should_stop())
1452 scan_object(object);
1453
1454 tmp = list_entry(object->gray_list.next, typeof(*object),
1455 gray_list);
1456
1457 /* remove the object from the list and release it */
1458 list_del(&object->gray_list);
1459 put_object(object);
1460
1461 object = tmp;
1462 }
1463 WARN_ON(!list_empty(&gray_list));
1464}
1465
1466/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001467 * Scan data sections and all the referenced memory blocks allocated via the
1468 * kernel's standard allocators. This function must be called with the
1469 * scan_mutex held.
1470 */
1471static void kmemleak_scan(void)
1472{
1473 unsigned long flags;
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001474 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001475 int i;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001476 int new_leaks = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001477
Catalin Marinasacf49682009-06-26 17:38:29 +01001478 jiffies_last_scan = jiffies;
1479
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001480 /* prepare the kmemleak_object's */
1481 rcu_read_lock();
1482 list_for_each_entry_rcu(object, &object_list, object_list) {
1483 spin_lock_irqsave(&object->lock, flags);
1484#ifdef DEBUG
1485 /*
1486 * With a few exceptions there should be a maximum of
1487 * 1 reference to any object at this point.
1488 */
1489 if (atomic_read(&object->use_count) > 1) {
Joe Perchesae281062009-06-23 14:40:26 +01001490 pr_debug("object->use_count = %d\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001491 atomic_read(&object->use_count));
1492 dump_object_info(object);
1493 }
1494#endif
1495 /* reset the reference count (whiten the object) */
1496 object->count = 0;
1497 if (color_gray(object) && get_object(object))
1498 list_add_tail(&object->gray_list, &gray_list);
1499
1500 spin_unlock_irqrestore(&object->lock, flags);
1501 }
1502 rcu_read_unlock();
1503
1504 /* data/bss scanning */
Catalin Marinas93ada572015-06-24 16:58:37 -07001505 scan_large_block(_sdata, _edata);
1506 scan_large_block(__bss_start, __bss_stop);
Kees Cook906f2a52017-03-31 15:11:58 -07001507 scan_large_block(__start_ro_after_init, __end_ro_after_init);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001508
1509#ifdef CONFIG_SMP
1510 /* per-cpu sections scanning */
1511 for_each_possible_cpu(i)
Catalin Marinas93ada572015-06-24 16:58:37 -07001512 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1513 __per_cpu_end + per_cpu_offset(i));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001514#endif
1515
1516 /*
Laura Abbott029aeff2011-11-15 23:49:09 +00001517 * Struct page scanning for each node.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001518 */
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001519 get_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001520 for_each_online_node(i) {
Cody P Schafer108bcc92013-02-22 16:35:23 -08001521 unsigned long start_pfn = node_start_pfn(i);
1522 unsigned long end_pfn = node_end_pfn(i);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001523 unsigned long pfn;
1524
1525 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1526 struct page *page;
1527
1528 if (!pfn_valid(pfn))
1529 continue;
1530 page = pfn_to_page(pfn);
1531 /* only scan if page is in use */
1532 if (page_count(page) == 0)
1533 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001534 scan_block(page, page + 1, NULL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001535 }
1536 }
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001537 put_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001538
1539 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001540 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001541 */
1542 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001543 struct task_struct *p, *g;
1544
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001545 read_lock(&tasklist_lock);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001546 do_each_thread(g, p) {
Catalin Marinas37df49f2016-10-27 17:46:47 -07001547 void *stack = try_get_task_stack(p);
1548 if (stack) {
1549 scan_block(stack, stack + THREAD_SIZE, NULL);
1550 put_task_stack(p);
1551 }
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001552 } while_each_thread(g, p);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001553 read_unlock(&tasklist_lock);
1554 }
1555
1556 /*
1557 * Scan the objects already referenced from the sections scanned
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001558 * above.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001559 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001560 scan_gray_list();
Catalin Marinas25873622009-07-07 10:32:58 +01001561
1562 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001563 * Check for new or unreferenced objects modified since the previous
1564 * scan and color them gray until the next scan.
Catalin Marinas25873622009-07-07 10:32:58 +01001565 */
1566 rcu_read_lock();
1567 list_for_each_entry_rcu(object, &object_list, object_list) {
1568 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001569 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1570 && update_checksum(object) && get_object(object)) {
1571 /* color it gray temporarily */
1572 object->count = object->min_count;
Catalin Marinas25873622009-07-07 10:32:58 +01001573 list_add_tail(&object->gray_list, &gray_list);
1574 }
1575 spin_unlock_irqrestore(&object->lock, flags);
1576 }
1577 rcu_read_unlock();
1578
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001579 /*
1580 * Re-scan the gray list for modified unreferenced objects.
1581 */
1582 scan_gray_list();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001583
1584 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001585 * If scanning was stopped do not report any new unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001586 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001587 if (scan_should_stop())
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001588 return;
1589
1590 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001591 * Scanning result reporting.
1592 */
1593 rcu_read_lock();
1594 list_for_each_entry_rcu(object, &object_list, object_list) {
1595 spin_lock_irqsave(&object->lock, flags);
1596 if (unreferenced_object(object) &&
1597 !(object->flags & OBJECT_REPORTED)) {
1598 object->flags |= OBJECT_REPORTED;
1599 new_leaks++;
1600 }
1601 spin_unlock_irqrestore(&object->lock, flags);
1602 }
1603 rcu_read_unlock();
1604
Li Zefandc9b3f42014-04-03 14:46:26 -07001605 if (new_leaks) {
1606 kmemleak_found_leaks = true;
1607
Joe Perches756a0252016-03-17 14:19:47 -07001608 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1609 new_leaks);
Li Zefandc9b3f42014-04-03 14:46:26 -07001610 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001611
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001612}
1613
1614/*
1615 * Thread function performing automatic memory scanning. Unreferenced objects
1616 * at the end of a memory scan are reported but only the first time.
1617 */
1618static int kmemleak_scan_thread(void *arg)
1619{
1620 static int first_run = 1;
1621
Joe Perchesae281062009-06-23 14:40:26 +01001622 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001623 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001624
1625 /*
1626 * Wait before the first scan to allow the system to fully initialize.
1627 */
1628 if (first_run) {
Vegard Nossum98c42d92016-07-28 15:48:32 -07001629 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001630 first_run = 0;
Vegard Nossum98c42d92016-07-28 15:48:32 -07001631 while (timeout && !kthread_should_stop())
1632 timeout = schedule_timeout_interruptible(timeout);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001633 }
1634
1635 while (!kthread_should_stop()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001636 signed long timeout = jiffies_scan_wait;
1637
1638 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001639 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001640 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001641
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001642 /* wait before the next scan */
1643 while (timeout && !kthread_should_stop())
1644 timeout = schedule_timeout_interruptible(timeout);
1645 }
1646
Joe Perchesae281062009-06-23 14:40:26 +01001647 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001648
1649 return 0;
1650}
1651
1652/*
1653 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001654 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001655 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001656static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001657{
1658 if (scan_thread)
1659 return;
1660 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1661 if (IS_ERR(scan_thread)) {
Joe Perches598d8092016-03-17 14:19:44 -07001662 pr_warn("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001663 scan_thread = NULL;
1664 }
1665}
1666
1667/*
1668 * Stop the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001669 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001670 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001671static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001672{
1673 if (scan_thread) {
1674 kthread_stop(scan_thread);
1675 scan_thread = NULL;
1676 }
1677}
1678
1679/*
1680 * Iterate over the object_list and return the first valid object at or after
1681 * the required position with its use_count incremented. The function triggers
1682 * a memory scanning when the pos argument points to the first position.
1683 */
1684static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1685{
1686 struct kmemleak_object *object;
1687 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001688 int err;
1689
1690 err = mutex_lock_interruptible(&scan_mutex);
1691 if (err < 0)
1692 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001693
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001694 rcu_read_lock();
1695 list_for_each_entry_rcu(object, &object_list, object_list) {
1696 if (n-- > 0)
1697 continue;
1698 if (get_object(object))
1699 goto out;
1700 }
1701 object = NULL;
1702out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001703 return object;
1704}
1705
1706/*
1707 * Return the next object in the object_list. The function decrements the
1708 * use_count of the previous object and increases that of the next one.
1709 */
1710static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1711{
1712 struct kmemleak_object *prev_obj = v;
1713 struct kmemleak_object *next_obj = NULL;
Michael Wang58fac092012-08-17 12:33:34 +08001714 struct kmemleak_object *obj = prev_obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001715
1716 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001717
Michael Wang58fac092012-08-17 12:33:34 +08001718 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001719 if (get_object(obj)) {
1720 next_obj = obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001721 break;
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001722 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001723 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001724
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001725 put_object(prev_obj);
1726 return next_obj;
1727}
1728
1729/*
1730 * Decrement the use_count of the last object required, if any.
1731 */
1732static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1733{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001734 if (!IS_ERR(v)) {
1735 /*
1736 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1737 * waiting was interrupted, so only release it if !IS_ERR.
1738 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001739 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001740 mutex_unlock(&scan_mutex);
1741 if (v)
1742 put_object(v);
1743 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001744}
1745
1746/*
1747 * Print the information for an unreferenced object to the seq file.
1748 */
1749static int kmemleak_seq_show(struct seq_file *seq, void *v)
1750{
1751 struct kmemleak_object *object = v;
1752 unsigned long flags;
1753
1754 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001755 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001756 print_unreferenced(seq, object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001757 spin_unlock_irqrestore(&object->lock, flags);
1758 return 0;
1759}
1760
1761static const struct seq_operations kmemleak_seq_ops = {
1762 .start = kmemleak_seq_start,
1763 .next = kmemleak_seq_next,
1764 .stop = kmemleak_seq_stop,
1765 .show = kmemleak_seq_show,
1766};
1767
1768static int kmemleak_open(struct inode *inode, struct file *file)
1769{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001770 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001771}
1772
Catalin Marinas189d84e2009-08-27 14:29:15 +01001773static int dump_str_object_info(const char *str)
1774{
1775 unsigned long flags;
1776 struct kmemleak_object *object;
1777 unsigned long addr;
1778
Abhijit Pawardc053732012-12-18 14:23:27 -08001779 if (kstrtoul(str, 0, &addr))
1780 return -EINVAL;
Catalin Marinas189d84e2009-08-27 14:29:15 +01001781 object = find_and_get_object(addr, 0);
1782 if (!object) {
1783 pr_info("Unknown object at 0x%08lx\n", addr);
1784 return -EINVAL;
1785 }
1786
1787 spin_lock_irqsave(&object->lock, flags);
1788 dump_object_info(object);
1789 spin_unlock_irqrestore(&object->lock, flags);
1790
1791 put_object(object);
1792 return 0;
1793}
1794
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001795/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001796 * We use grey instead of black to ensure we can do future scans on the same
1797 * objects. If we did not do future scans these black objects could
1798 * potentially contain references to newly allocated objects in the future and
1799 * we'd end up with false positives.
1800 */
1801static void kmemleak_clear(void)
1802{
1803 struct kmemleak_object *object;
1804 unsigned long flags;
1805
1806 rcu_read_lock();
1807 list_for_each_entry_rcu(object, &object_list, object_list) {
1808 spin_lock_irqsave(&object->lock, flags);
1809 if ((object->flags & OBJECT_REPORTED) &&
1810 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001811 __paint_it(object, KMEMLEAK_GREY);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001812 spin_unlock_irqrestore(&object->lock, flags);
1813 }
1814 rcu_read_unlock();
Li Zefandc9b3f42014-04-03 14:46:26 -07001815
1816 kmemleak_found_leaks = false;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001817}
1818
Li Zefanc89da702014-04-03 14:46:27 -07001819static void __kmemleak_do_cleanup(void);
1820
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001821/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001822 * File write operation to configure kmemleak at run-time. The following
1823 * commands can be written to the /sys/kernel/debug/kmemleak file:
1824 * off - disable kmemleak (irreversible)
1825 * stack=on - enable the task stacks scanning
1826 * stack=off - disable the tasks stacks scanning
1827 * scan=on - start the automatic memory scanning thread
1828 * scan=off - stop the automatic memory scanning thread
1829 * scan=... - set the automatic memory scanning period in seconds (0 to
1830 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001831 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001832 * clear - mark all current reported unreferenced kmemleak objects as
Li Zefanc89da702014-04-03 14:46:27 -07001833 * grey to ignore printing them, or free all kmemleak objects
1834 * if kmemleak has been disabled.
Catalin Marinas189d84e2009-08-27 14:29:15 +01001835 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001836 */
1837static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1838 size_t size, loff_t *ppos)
1839{
1840 char buf[64];
1841 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001842 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001843
1844 buf_size = min(size, (sizeof(buf) - 1));
1845 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1846 return -EFAULT;
1847 buf[buf_size] = 0;
1848
Catalin Marinasb87324d2009-07-07 10:32:58 +01001849 ret = mutex_lock_interruptible(&scan_mutex);
1850 if (ret < 0)
1851 return ret;
1852
Li Zefanc89da702014-04-03 14:46:27 -07001853 if (strncmp(buf, "clear", 5) == 0) {
Li Zefan8910ae82014-04-03 14:46:29 -07001854 if (kmemleak_enabled)
Li Zefanc89da702014-04-03 14:46:27 -07001855 kmemleak_clear();
1856 else
1857 __kmemleak_do_cleanup();
1858 goto out;
1859 }
1860
Li Zefan8910ae82014-04-03 14:46:29 -07001861 if (!kmemleak_enabled) {
Li Zefanc89da702014-04-03 14:46:27 -07001862 ret = -EBUSY;
1863 goto out;
1864 }
1865
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001866 if (strncmp(buf, "off", 3) == 0)
1867 kmemleak_disable();
1868 else if (strncmp(buf, "stack=on", 8) == 0)
1869 kmemleak_stack_scan = 1;
1870 else if (strncmp(buf, "stack=off", 9) == 0)
1871 kmemleak_stack_scan = 0;
1872 else if (strncmp(buf, "scan=on", 7) == 0)
1873 start_scan_thread();
1874 else if (strncmp(buf, "scan=off", 8) == 0)
1875 stop_scan_thread();
1876 else if (strncmp(buf, "scan=", 5) == 0) {
1877 unsigned long secs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001878
Jingoo Han3dbb95f2013-09-11 14:20:25 -07001879 ret = kstrtoul(buf + 5, 0, &secs);
Catalin Marinasb87324d2009-07-07 10:32:58 +01001880 if (ret < 0)
1881 goto out;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001882 stop_scan_thread();
1883 if (secs) {
1884 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1885 start_scan_thread();
1886 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001887 } else if (strncmp(buf, "scan", 4) == 0)
1888 kmemleak_scan();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001889 else if (strncmp(buf, "dump=", 5) == 0)
1890 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001891 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001892 ret = -EINVAL;
1893
1894out:
1895 mutex_unlock(&scan_mutex);
1896 if (ret < 0)
1897 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001898
1899 /* ignore the rest of the buffer, only one command at a time */
1900 *ppos += size;
1901 return size;
1902}
1903
1904static const struct file_operations kmemleak_fops = {
1905 .owner = THIS_MODULE,
1906 .open = kmemleak_open,
1907 .read = seq_read,
1908 .write = kmemleak_write,
1909 .llseek = seq_lseek,
Li Zefan5f3bf192014-04-03 14:46:28 -07001910 .release = seq_release,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001911};
1912
Li Zefanc89da702014-04-03 14:46:27 -07001913static void __kmemleak_do_cleanup(void)
1914{
1915 struct kmemleak_object *object;
1916
1917 rcu_read_lock();
1918 list_for_each_entry_rcu(object, &object_list, object_list)
1919 delete_object_full(object->pointer);
1920 rcu_read_unlock();
1921}
1922
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001923/*
Catalin Marinas74341702011-09-29 11:50:07 +01001924 * Stop the memory scanning thread and free the kmemleak internal objects if
1925 * no previous scan thread (otherwise, kmemleak may still have some useful
1926 * information on memory leaks).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001927 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001928static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001929{
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001930 stop_scan_thread();
1931
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001932 /*
1933 * Once the scan thread has stopped, it is safe to no longer track
1934 * object freeing. Ordering of the scan thread stopping and the memory
1935 * accesses below is guaranteed by the kthread_stop() function.
1936 */
1937 kmemleak_free_enabled = 0;
1938
Li Zefanc89da702014-04-03 14:46:27 -07001939 if (!kmemleak_found_leaks)
1940 __kmemleak_do_cleanup();
1941 else
Joe Perches756a0252016-03-17 14:19:47 -07001942 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 +01001943}
1944
Catalin Marinas179a8102009-09-07 10:14:42 +01001945static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001946
1947/*
1948 * Disable kmemleak. No memory allocation/freeing will be traced once this
1949 * function is called. Disabling kmemleak is an irreversible operation.
1950 */
1951static void kmemleak_disable(void)
1952{
1953 /* atomically check whether it was already invoked */
Li Zefan8910ae82014-04-03 14:46:29 -07001954 if (cmpxchg(&kmemleak_error, 0, 1))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001955 return;
1956
1957 /* stop any memory operation tracing */
Li Zefan8910ae82014-04-03 14:46:29 -07001958 kmemleak_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001959
1960 /* check whether it is too early for a kernel thread */
Li Zefan8910ae82014-04-03 14:46:29 -07001961 if (kmemleak_initialized)
Catalin Marinas179a8102009-09-07 10:14:42 +01001962 schedule_work(&cleanup_work);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001963 else
1964 kmemleak_free_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001965
1966 pr_info("Kernel memory leak detector disabled\n");
1967}
1968
1969/*
1970 * Allow boot-time kmemleak disabling (enabled by default).
1971 */
1972static int kmemleak_boot_config(char *str)
1973{
1974 if (!str)
1975 return -EINVAL;
1976 if (strcmp(str, "off") == 0)
1977 kmemleak_disable();
Jason Baronab0155a2010-07-19 11:54:17 +01001978 else if (strcmp(str, "on") == 0)
1979 kmemleak_skip_disable = 1;
1980 else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001981 return -EINVAL;
1982 return 0;
1983}
1984early_param("kmemleak", kmemleak_boot_config);
1985
Catalin Marinas5f790202011-09-28 12:17:03 +01001986static void __init print_log_trace(struct early_log *log)
1987{
1988 struct stack_trace trace;
1989
1990 trace.nr_entries = log->trace_len;
1991 trace.entries = log->trace;
1992
1993 pr_notice("Early log backtrace:\n");
1994 print_stack_trace(&trace, 2);
1995}
1996
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001997/*
Catalin Marinas20301172009-06-17 18:29:04 +01001998 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001999 */
2000void __init kmemleak_init(void)
2001{
2002 int i;
2003 unsigned long flags;
2004
Jason Baronab0155a2010-07-19 11:54:17 +01002005#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
2006 if (!kmemleak_skip_disable) {
Catalin Marinas3551a922014-05-09 15:36:59 -07002007 kmemleak_early_log = 0;
Jason Baronab0155a2010-07-19 11:54:17 +01002008 kmemleak_disable();
2009 return;
2010 }
2011#endif
2012
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002013 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
2014 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
2015
2016 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
2017 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002018
Wang Kai21cd3a62015-09-08 15:03:41 -07002019 if (crt_early_log > ARRAY_SIZE(early_log))
Joe Perches598d8092016-03-17 14:19:44 -07002020 pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
2021 crt_early_log);
Catalin Marinasb6693002011-09-28 17:22:56 +01002022
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002023 /* the kernel is still in UP mode, so disabling the IRQs is enough */
2024 local_irq_save(flags);
Catalin Marinas3551a922014-05-09 15:36:59 -07002025 kmemleak_early_log = 0;
Li Zefan8910ae82014-04-03 14:46:29 -07002026 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +01002027 local_irq_restore(flags);
2028 return;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002029 } else {
Li Zefan8910ae82014-04-03 14:46:29 -07002030 kmemleak_enabled = 1;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002031 kmemleak_free_enabled = 1;
2032 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002033 local_irq_restore(flags);
2034
2035 /*
2036 * This is the point where tracking allocations is safe. Automatic
2037 * scanning is started during the late initcall. Add the early logged
2038 * callbacks to the kmemleak infrastructure.
2039 */
2040 for (i = 0; i < crt_early_log; i++) {
2041 struct early_log *log = &early_log[i];
2042
2043 switch (log->op_type) {
2044 case KMEMLEAK_ALLOC:
Catalin Marinasfd678962009-08-27 14:29:17 +01002045 early_alloc(log);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002046 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002047 case KMEMLEAK_ALLOC_PERCPU:
2048 early_alloc_percpu(log);
2049 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002050 case KMEMLEAK_FREE:
2051 kmemleak_free(log->ptr);
2052 break;
Catalin Marinas53238a62009-07-07 10:33:00 +01002053 case KMEMLEAK_FREE_PART:
2054 kmemleak_free_part(log->ptr, log->size);
2055 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002056 case KMEMLEAK_FREE_PERCPU:
2057 kmemleak_free_percpu(log->ptr);
2058 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002059 case KMEMLEAK_NOT_LEAK:
2060 kmemleak_not_leak(log->ptr);
2061 break;
2062 case KMEMLEAK_IGNORE:
2063 kmemleak_ignore(log->ptr);
2064 break;
2065 case KMEMLEAK_SCAN_AREA:
Catalin Marinasc017b4b2009-10-28 13:33:09 +00002066 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002067 break;
2068 case KMEMLEAK_NO_SCAN:
2069 kmemleak_no_scan(log->ptr);
2070 break;
Catalin Marinas94f4a162017-07-06 15:40:22 -07002071 case KMEMLEAK_SET_EXCESS_REF:
2072 object_set_excess_ref((unsigned long)log->ptr,
2073 log->excess_ref);
2074 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002075 default:
Catalin Marinas5f790202011-09-28 12:17:03 +01002076 kmemleak_warn("Unknown early log operation: %d\n",
2077 log->op_type);
2078 }
2079
Li Zefan8910ae82014-04-03 14:46:29 -07002080 if (kmemleak_warning) {
Catalin Marinas5f790202011-09-28 12:17:03 +01002081 print_log_trace(log);
Li Zefan8910ae82014-04-03 14:46:29 -07002082 kmemleak_warning = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002083 }
2084 }
2085}
2086
2087/*
2088 * Late initialization function.
2089 */
2090static int __init kmemleak_late_init(void)
2091{
2092 struct dentry *dentry;
2093
Li Zefan8910ae82014-04-03 14:46:29 -07002094 kmemleak_initialized = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002095
Li Zefan8910ae82014-04-03 14:46:29 -07002096 if (kmemleak_error) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002097 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002098 * Some error occurred and kmemleak was disabled. There is a
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002099 * small chance that kmemleak_disable() was called immediately
2100 * after setting kmemleak_initialized and we may end up with
2101 * two clean-up threads but serialized by scan_mutex.
2102 */
Catalin Marinas179a8102009-09-07 10:14:42 +01002103 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002104 return -ENOMEM;
2105 }
2106
2107 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
2108 &kmemleak_fops);
2109 if (!dentry)
Joe Perches598d8092016-03-17 14:19:44 -07002110 pr_warn("Failed to create the debugfs kmemleak file\n");
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002111 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002112 start_scan_thread();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002113 mutex_unlock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002114
2115 pr_info("Kernel memory leak detector initialized\n");
2116
2117 return 0;
2118}
2119late_initcall(kmemleak_late_init);