blob: 9a085d525bbce1bd4aabb4599236d2874c964850 [file] [log] [blame]
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>
Catalin Marinas9099dae2016-10-11 13:55:11 -070094#include <linux/bootmem.h>
95#include <linux/pfn.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010096#include <linux/mmzone.h>
97#include <linux/slab.h>
98#include <linux/thread_info.h>
99#include <linux/err.h>
100#include <linux/uaccess.h>
101#include <linux/string.h>
102#include <linux/nodemask.h>
103#include <linux/mm.h>
Catalin Marinas179a8102009-09-07 10:14:42 +0100104#include <linux/workqueue.h>
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000105#include <linux/crc32.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100106
107#include <asm/sections.h>
108#include <asm/processor.h>
Arun Sharma600634972011-07-26 16:09:06 -0700109#include <linux/atomic.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100110
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -0800111#include <linux/kasan.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100112#include <linux/kmemleak.h>
Laura Abbott029aeff2011-11-15 23:49:09 +0000113#include <linux/memory_hotplug.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100114
115/*
116 * Kmemleak configuration and common defines.
117 */
118#define MAX_TRACE 16 /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100119#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100120#define SECS_FIRST_SCAN 60 /* delay before the first scan */
121#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
Catalin Marinasaf986032009-08-27 14:29:12 +0100122#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100123
124#define BYTES_PER_POINTER sizeof(void *)
125
Catalin Marinas216c04b2009-06-17 18:29:02 +0100126/* GFP bitmask for kmemleak internal allocations */
Vladimir Davydov20b5c302016-01-14 15:18:08 -0800127#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000128 __GFP_NORETRY | __GFP_NOMEMALLOC | \
Dmitry Vyukovd9570ee2018-01-12 16:53:10 -0800129 __GFP_NOWARN | __GFP_NOFAIL)
Catalin Marinas216c04b2009-06-17 18:29:02 +0100130
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100131/* scanning area inside a memory block */
132struct kmemleak_scan_area {
133 struct hlist_node node;
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000134 unsigned long start;
135 size_t size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100136};
137
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700138#define KMEMLEAK_GREY 0
139#define KMEMLEAK_BLACK -1
140
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100141/*
142 * Structure holding the metadata for each allocated memory block.
143 * Modifications to such objects should be made while holding the
144 * object->lock. Insertions or deletions from object_list, gray_list or
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700145 * rb_node are already protected by the corresponding locks or mutex (see
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100146 * the notes on locking above). These objects are reference-counted
147 * (use_count) and freed using the RCU mechanism.
148 */
149struct kmemleak_object {
150 spinlock_t lock;
Catalin Marinasf66abf02017-07-06 15:40:16 -0700151 unsigned int flags; /* object status flags */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100152 struct list_head object_list;
153 struct list_head gray_list;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700154 struct rb_node rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100155 struct rcu_head rcu; /* object_list lockless traversal */
156 /* object usage count; object freed when use_count == 0 */
157 atomic_t use_count;
158 unsigned long pointer;
159 size_t size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700160 /* pass surplus references to this pointer */
161 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100162 /* minimum number of a pointers found before it is considered leak */
163 int min_count;
164 /* the total number of pointers found pointing to this object */
165 int count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000166 /* checksum for detecting modified objects */
167 u32 checksum;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100168 /* memory ranges to be scanned inside an object (empty for all) */
169 struct hlist_head area_list;
170 unsigned long trace[MAX_TRACE];
171 unsigned int trace_len;
172 unsigned long jiffies; /* creation timestamp */
173 pid_t pid; /* pid of the current task */
174 char comm[TASK_COMM_LEN]; /* executable name */
175};
176
177/* flag representing the memory block allocation status */
178#define OBJECT_ALLOCATED (1 << 0)
179/* flag set after the first reporting of an unreference object */
180#define OBJECT_REPORTED (1 << 1)
181/* flag set to not scan the object */
182#define OBJECT_NO_SCAN (1 << 2)
183
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100184/* number of bytes to print per line; must be 16 or 32 */
185#define HEX_ROW_SIZE 16
186/* number of bytes to print at a time (1, 2, 4, 8) */
187#define HEX_GROUP_SIZE 1
188/* include ASCII after the hex output */
189#define HEX_ASCII 1
190/* max number of lines to be printed */
191#define HEX_MAX_LINES 2
192
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100193/* the list of all allocated objects */
194static LIST_HEAD(object_list);
195/* the list of gray-colored objects (see color_gray comment below) */
196static LIST_HEAD(gray_list);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700197/* search tree for object boundaries */
198static struct rb_root object_tree_root = RB_ROOT;
199/* rw_lock protecting the access to object_list and object_tree_root */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100200static DEFINE_RWLOCK(kmemleak_lock);
201
202/* allocation caches for kmemleak internal data */
203static struct kmem_cache *object_cache;
204static struct kmem_cache *scan_area_cache;
205
206/* set if tracing memory operations is enabled */
Li Zefan8910ae82014-04-03 14:46:29 -0700207static int kmemleak_enabled;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700208/* same as above but only for the kmemleak_free() callback */
209static int kmemleak_free_enabled;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100210/* set in the late_initcall if there were no errors */
Li Zefan8910ae82014-04-03 14:46:29 -0700211static int kmemleak_initialized;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100212/* enables or disables early logging of the memory operations */
Li Zefan8910ae82014-04-03 14:46:29 -0700213static int kmemleak_early_log = 1;
Catalin Marinas5f790202011-09-28 12:17:03 +0100214/* set if a kmemleak warning was issued */
Li Zefan8910ae82014-04-03 14:46:29 -0700215static int kmemleak_warning;
Catalin Marinas5f790202011-09-28 12:17:03 +0100216/* set if a fatal kmemleak error has occurred */
Li Zefan8910ae82014-04-03 14:46:29 -0700217static int kmemleak_error;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100218
219/* minimum and maximum address that may be valid pointers */
220static unsigned long min_addr = ULONG_MAX;
221static unsigned long max_addr;
222
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100223static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100224/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100225static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100226static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100227/* delay between automatic memory scannings */
228static signed long jiffies_scan_wait;
229/* enables or disables the task stacks scanning */
Catalin Marinase0a2a162009-06-26 17:38:25 +0100230static int kmemleak_stack_scan = 1;
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100231/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100232static DEFINE_MUTEX(scan_mutex);
Jason Baronab0155a2010-07-19 11:54:17 +0100233/* setting kmemleak=on, will set this var, skipping the disable */
234static int kmemleak_skip_disable;
Li Zefandc9b3f42014-04-03 14:46:26 -0700235/* If there are leaks that can be reported */
236static bool kmemleak_found_leaks;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100237
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100238/*
Catalin Marinas20301172009-06-17 18:29:04 +0100239 * Early object allocation/freeing logging. Kmemleak is initialized after the
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100240 * kernel allocator. However, both the kernel allocator and kmemleak may
Catalin Marinas20301172009-06-17 18:29:04 +0100241 * allocate memory blocks which need to be tracked. Kmemleak defines an
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100242 * arbitrary buffer to hold the allocation/freeing information before it is
243 * fully initialized.
244 */
245
246/* kmemleak operation type for early logging */
247enum {
248 KMEMLEAK_ALLOC,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100249 KMEMLEAK_ALLOC_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100250 KMEMLEAK_FREE,
Catalin Marinas53238a62009-07-07 10:33:00 +0100251 KMEMLEAK_FREE_PART,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100252 KMEMLEAK_FREE_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100253 KMEMLEAK_NOT_LEAK,
254 KMEMLEAK_IGNORE,
255 KMEMLEAK_SCAN_AREA,
Catalin Marinas94f4a162017-07-06 15:40:22 -0700256 KMEMLEAK_NO_SCAN,
257 KMEMLEAK_SET_EXCESS_REF
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100258};
259
260/*
261 * Structure holding the information passed to kmemleak callbacks during the
262 * early logging.
263 */
264struct early_log {
265 int op_type; /* kmemleak operation type */
Catalin Marinasf66abf02017-07-06 15:40:16 -0700266 int min_count; /* minimum reference count */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100267 const void *ptr; /* allocated/freed memory block */
Catalin Marinas94f4a162017-07-06 15:40:22 -0700268 union {
269 size_t size; /* memory block size */
270 unsigned long excess_ref; /* surplus reference passing */
271 };
Catalin Marinasfd678962009-08-27 14:29:17 +0100272 unsigned long trace[MAX_TRACE]; /* stack trace */
273 unsigned int trace_len; /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100274};
275
276/* early logging buffer and current position */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100277static struct early_log
278 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
279static int crt_early_log __initdata;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100280
281static void kmemleak_disable(void);
282
283/*
284 * Print a warning and dump the stack trace.
285 */
Catalin Marinas5f790202011-09-28 12:17:03 +0100286#define kmemleak_warn(x...) do { \
Joe Perches598d8092016-03-17 14:19:44 -0700287 pr_warn(x); \
Catalin Marinas5f790202011-09-28 12:17:03 +0100288 dump_stack(); \
Li Zefan8910ae82014-04-03 14:46:29 -0700289 kmemleak_warning = 1; \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100290} while (0)
291
292/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300293 * Macro invoked when a serious kmemleak condition occurred and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100294 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100295 * tracing no longer available.
296 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100297#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100298 kmemleak_warn(x); \
299 kmemleak_disable(); \
300} while (0)
301
302/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100303 * Printing of the objects hex dump to the seq file. The number of lines to be
304 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
305 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
306 * with the object->lock held.
307 */
308static void hex_dump_object(struct seq_file *seq,
309 struct kmemleak_object *object)
310{
311 const u8 *ptr = (const u8 *)object->pointer;
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700312 size_t len;
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100313
314 /* limit the number of lines to HEX_MAX_LINES */
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700315 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100316
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700317 seq_printf(seq, " hex dump (first %zu bytes):\n", len);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700318 kasan_disable_current();
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700319 seq_hex_dump(seq, " ", DUMP_PREFIX_NONE, HEX_ROW_SIZE,
320 HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700321 kasan_enable_current();
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100322}
323
324/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100325 * Object colors, encoded with count and min_count:
326 * - white - orphan object, not enough references to it (count < min_count)
327 * - gray - not orphan, not marked as false positive (min_count == 0) or
328 * sufficient references to it (count >= min_count)
329 * - black - ignore, it doesn't contain references (e.g. text section)
330 * (min_count == -1). No function defined for this color.
331 * Newly created objects don't have any color assigned (object->count == -1)
332 * before the next memory scan when they become white.
333 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100334static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100335{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700336 return object->count != KMEMLEAK_BLACK &&
337 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100338}
339
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100340static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100341{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700342 return object->min_count != KMEMLEAK_BLACK &&
343 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100344}
345
346/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100347 * Objects are considered unreferenced only if their color is white, they have
348 * not be deleted and have a minimum age to avoid false positives caused by
349 * pointers temporarily stored in CPU registers.
350 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100351static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100352{
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000353 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100354 time_before_eq(object->jiffies + jiffies_min_age,
355 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100356}
357
358/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100359 * Printing of the unreferenced objects information to the seq file. The
360 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100361 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100362static void print_unreferenced(struct seq_file *seq,
363 struct kmemleak_object *object)
364{
365 int i;
Catalin Marinasfefdd332009-10-28 13:33:12 +0000366 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100367
Catalin Marinasbab4a342009-06-26 17:38:26 +0100368 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
369 object->pointer, object->size);
Catalin Marinasfefdd332009-10-28 13:33:12 +0000370 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
371 object->comm, object->pid, object->jiffies,
372 msecs_age / 1000, msecs_age % 1000);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100373 hex_dump_object(seq, object);
Catalin Marinasbab4a342009-06-26 17:38:26 +0100374 seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100375
376 for (i = 0; i < object->trace_len; i++) {
377 void *ptr = (void *)object->trace[i];
Catalin Marinasbab4a342009-06-26 17:38:26 +0100378 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100379 }
380}
381
382/*
383 * Print the kmemleak_object information. This function is used mainly for
384 * debugging special cases when kmemleak operations. It must be called with
385 * the object->lock held.
386 */
387static void dump_object_info(struct kmemleak_object *object)
388{
389 struct stack_trace trace;
390
391 trace.nr_entries = object->trace_len;
392 trace.entries = object->trace;
393
Joe Perchesae281062009-06-23 14:40:26 +0100394 pr_notice("Object 0x%08lx (size %zu):\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700395 object->pointer, object->size);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100396 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
397 object->comm, object->pid, object->jiffies);
398 pr_notice(" min_count = %d\n", object->min_count);
399 pr_notice(" count = %d\n", object->count);
Catalin Marinasf66abf02017-07-06 15:40:16 -0700400 pr_notice(" flags = 0x%x\n", object->flags);
Jianpeng Maaae0ad72014-06-06 14:38:16 -0700401 pr_notice(" checksum = %u\n", object->checksum);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100402 pr_notice(" backtrace:\n");
403 print_stack_trace(&trace, 4);
404}
405
406/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700407 * Look-up a memory block metadata (kmemleak_object) in the object search
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100408 * tree based on a pointer value. If alias is 0, only values pointing to the
409 * beginning of the memory block are allowed. The kmemleak_lock must be held
410 * when calling this function.
411 */
412static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
413{
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700414 struct rb_node *rb = object_tree_root.rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100415
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700416 while (rb) {
417 struct kmemleak_object *object =
418 rb_entry(rb, struct kmemleak_object, rb_node);
419 if (ptr < object->pointer)
420 rb = object->rb_node.rb_left;
421 else if (object->pointer + object->size <= ptr)
422 rb = object->rb_node.rb_right;
423 else if (object->pointer == ptr || alias)
424 return object;
425 else {
Catalin Marinas5f790202011-09-28 12:17:03 +0100426 kmemleak_warn("Found object by alias at 0x%08lx\n",
427 ptr);
Catalin Marinasa7686a42010-07-19 11:54:16 +0100428 dump_object_info(object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700429 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100430 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700431 }
432 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100433}
434
435/*
436 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
437 * that once an object's use_count reached 0, the RCU freeing was already
438 * registered and the object should no longer be used. This function must be
439 * called under the protection of rcu_read_lock().
440 */
441static int get_object(struct kmemleak_object *object)
442{
443 return atomic_inc_not_zero(&object->use_count);
444}
445
446/*
447 * RCU callback to free a kmemleak_object.
448 */
449static void free_object_rcu(struct rcu_head *rcu)
450{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800451 struct hlist_node *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100452 struct kmemleak_scan_area *area;
453 struct kmemleak_object *object =
454 container_of(rcu, struct kmemleak_object, rcu);
455
456 /*
457 * Once use_count is 0 (guaranteed by put_object), there is no other
458 * code accessing this object, hence no need for locking.
459 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800460 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
461 hlist_del(&area->node);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100462 kmem_cache_free(scan_area_cache, area);
463 }
464 kmem_cache_free(object_cache, object);
465}
466
467/*
468 * Decrement the object use_count. Once the count is 0, free the object using
469 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
470 * delete_object() path, the delayed RCU freeing ensures that there is no
471 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
472 * is also possible.
473 */
474static void put_object(struct kmemleak_object *object)
475{
476 if (!atomic_dec_and_test(&object->use_count))
477 return;
478
479 /* should only get here after delete_object was called */
480 WARN_ON(object->flags & OBJECT_ALLOCATED);
481
482 call_rcu(&object->rcu, free_object_rcu);
483}
484
485/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700486 * Look up an object in the object search tree and increase its use_count.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100487 */
488static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
489{
490 unsigned long flags;
Alexey Klimov9fbed252015-11-05 18:45:57 -0800491 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100492
493 rcu_read_lock();
494 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -0700495 object = lookup_object(ptr, alias);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100496 read_unlock_irqrestore(&kmemleak_lock, flags);
497
498 /* check whether the object is still available */
499 if (object && !get_object(object))
500 object = NULL;
501 rcu_read_unlock();
502
503 return object;
504}
505
506/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700507 * Look up an object in the object search tree and remove it from both
508 * object_tree_root and object_list. The returned object's use_count should be
509 * at least 1, as initially set by create_object().
510 */
511static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
512{
513 unsigned long flags;
514 struct kmemleak_object *object;
515
516 write_lock_irqsave(&kmemleak_lock, flags);
517 object = lookup_object(ptr, alias);
518 if (object) {
519 rb_erase(&object->rb_node, &object_tree_root);
520 list_del_rcu(&object->object_list);
521 }
522 write_unlock_irqrestore(&kmemleak_lock, flags);
523
524 return object;
525}
526
527/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100528 * Save stack trace to the given array of MAX_TRACE size.
529 */
530static int __save_stack_trace(unsigned long *trace)
531{
532 struct stack_trace stack_trace;
533
534 stack_trace.max_entries = MAX_TRACE;
535 stack_trace.nr_entries = 0;
536 stack_trace.entries = trace;
537 stack_trace.skip = 2;
538 save_stack_trace(&stack_trace);
539
540 return stack_trace.nr_entries;
541}
542
543/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100544 * Create the metadata (struct kmemleak_object) corresponding to an allocated
545 * memory block and add it to the object_list and object_tree_root.
546 */
Catalin Marinasfd678962009-08-27 14:29:17 +0100547static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
548 int min_count, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100549{
550 unsigned long flags;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700551 struct kmemleak_object *object, *parent;
552 struct rb_node **link, *rb_parent;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100553
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000554 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100555 if (!object) {
Joe Perches598d8092016-03-17 14:19:44 -0700556 pr_warn("Cannot allocate a kmemleak_object structure\n");
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000557 kmemleak_disable();
Catalin Marinasfd678962009-08-27 14:29:17 +0100558 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100559 }
560
561 INIT_LIST_HEAD(&object->object_list);
562 INIT_LIST_HEAD(&object->gray_list);
563 INIT_HLIST_HEAD(&object->area_list);
564 spin_lock_init(&object->lock);
565 atomic_set(&object->use_count, 1);
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000566 object->flags = OBJECT_ALLOCATED;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100567 object->pointer = ptr;
568 object->size = size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700569 object->excess_ref = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100570 object->min_count = min_count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000571 object->count = 0; /* white color initially */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100572 object->jiffies = jiffies;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000573 object->checksum = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100574
575 /* task information */
576 if (in_irq()) {
577 object->pid = 0;
578 strncpy(object->comm, "hardirq", sizeof(object->comm));
579 } else if (in_softirq()) {
580 object->pid = 0;
581 strncpy(object->comm, "softirq", sizeof(object->comm));
582 } else {
583 object->pid = current->pid;
584 /*
585 * There is a small chance of a race with set_task_comm(),
586 * however using get_task_comm() here may cause locking
587 * dependency issues with current->alloc_lock. In the worst
588 * case, the command line is not correct.
589 */
590 strncpy(object->comm, current->comm, sizeof(object->comm));
591 }
592
593 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100594 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100595
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100596 write_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100597
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100598 min_addr = min(min_addr, ptr);
599 max_addr = max(max_addr, ptr + size);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700600 link = &object_tree_root.rb_node;
601 rb_parent = NULL;
602 while (*link) {
603 rb_parent = *link;
604 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
605 if (ptr + size <= parent->pointer)
606 link = &parent->rb_node.rb_left;
607 else if (parent->pointer + parent->size <= ptr)
608 link = &parent->rb_node.rb_right;
609 else {
Joe Perches756a0252016-03-17 14:19:47 -0700610 kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700611 ptr);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700612 /*
613 * No need for parent->lock here since "parent" cannot
614 * be freed while the kmemleak_lock is held.
615 */
616 dump_object_info(parent);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700617 kmem_cache_free(object_cache, object);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700618 object = NULL;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700619 goto out;
620 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100621 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700622 rb_link_node(&object->rb_node, rb_parent, link);
623 rb_insert_color(&object->rb_node, &object_tree_root);
624
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100625 list_add_tail_rcu(&object->object_list, &object_list);
626out:
627 write_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinasfd678962009-08-27 14:29:17 +0100628 return object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100629}
630
631/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700632 * Mark the object as not allocated and schedule RCU freeing via put_object().
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100633 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100634static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100635{
636 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100637
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100638 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinase781a9a2015-06-24 16:58:29 -0700639 WARN_ON(atomic_read(&object->use_count) < 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100640
641 /*
642 * Locking here also ensures that the corresponding memory block
643 * cannot be freed when it is being scanned.
644 */
645 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100646 object->flags &= ~OBJECT_ALLOCATED;
647 spin_unlock_irqrestore(&object->lock, flags);
648 put_object(object);
649}
650
651/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100652 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
653 * delete it.
654 */
655static void delete_object_full(unsigned long ptr)
656{
657 struct kmemleak_object *object;
658
Catalin Marinase781a9a2015-06-24 16:58:29 -0700659 object = find_and_remove_object(ptr, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100660 if (!object) {
661#ifdef DEBUG
662 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
663 ptr);
664#endif
665 return;
666 }
667 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100668}
669
670/*
671 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
672 * delete it. If the memory block is partially freed, the function may create
673 * additional metadata for the remaining parts of the block.
674 */
675static void delete_object_part(unsigned long ptr, size_t size)
676{
677 struct kmemleak_object *object;
678 unsigned long start, end;
679
Catalin Marinase781a9a2015-06-24 16:58:29 -0700680 object = find_and_remove_object(ptr, 1);
Catalin Marinas53238a62009-07-07 10:33:00 +0100681 if (!object) {
682#ifdef DEBUG
Joe Perches756a0252016-03-17 14:19:47 -0700683 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
684 ptr, size);
Catalin Marinas53238a62009-07-07 10:33:00 +0100685#endif
686 return;
687 }
Catalin Marinas53238a62009-07-07 10:33:00 +0100688
689 /*
690 * Create one or two objects that may result from the memory block
691 * split. Note that partial freeing is only done by free_bootmem() and
692 * this happens before kmemleak_init() is called. The path below is
693 * only executed during early log recording in kmemleak_init(), so
694 * GFP_KERNEL is enough.
695 */
696 start = object->pointer;
697 end = object->pointer + object->size;
698 if (ptr > start)
699 create_object(start, ptr - start, object->min_count,
700 GFP_KERNEL);
701 if (ptr + size < end)
702 create_object(ptr + size, end - ptr - size, object->min_count,
703 GFP_KERNEL);
704
Catalin Marinase781a9a2015-06-24 16:58:29 -0700705 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100706}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700707
708static void __paint_it(struct kmemleak_object *object, int color)
709{
710 object->min_count = color;
711 if (color == KMEMLEAK_BLACK)
712 object->flags |= OBJECT_NO_SCAN;
713}
714
715static void paint_it(struct kmemleak_object *object, int color)
716{
717 unsigned long flags;
718
719 spin_lock_irqsave(&object->lock, flags);
720 __paint_it(object, color);
721 spin_unlock_irqrestore(&object->lock, flags);
722}
723
724static void paint_ptr(unsigned long ptr, int color)
725{
726 struct kmemleak_object *object;
727
728 object = find_and_get_object(ptr, 0);
729 if (!object) {
Joe Perches756a0252016-03-17 14:19:47 -0700730 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
731 ptr,
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700732 (color == KMEMLEAK_GREY) ? "Grey" :
733 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
734 return;
735 }
736 paint_it(object, color);
737 put_object(object);
738}
739
Catalin Marinas53238a62009-07-07 10:33:00 +0100740/*
Holger Hans Peter Freyther145b64b2010-07-22 19:54:13 +0800741 * Mark an object permanently as gray-colored so that it can no longer be
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100742 * reported as a leak. This is used in general to mark a false positive.
743 */
744static void make_gray_object(unsigned long ptr)
745{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700746 paint_ptr(ptr, KMEMLEAK_GREY);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100747}
748
749/*
750 * Mark the object as black-colored so that it is ignored from scans and
751 * reporting.
752 */
753static void make_black_object(unsigned long ptr)
754{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700755 paint_ptr(ptr, KMEMLEAK_BLACK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100756}
757
758/*
759 * Add a scanning area to the object. If at least one such area is added,
760 * kmemleak will only scan these ranges rather than the whole memory block.
761 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000762static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100763{
764 unsigned long flags;
765 struct kmemleak_object *object;
766 struct kmemleak_scan_area *area;
767
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000768 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100769 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100770 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
771 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100772 return;
773 }
774
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000775 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100776 if (!area) {
Joe Perches598d8092016-03-17 14:19:44 -0700777 pr_warn("Cannot allocate a scan area\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100778 goto out;
779 }
780
781 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas7f88f882013-11-12 15:07:45 -0800782 if (size == SIZE_MAX) {
783 size = object->pointer + object->size - ptr;
784 } else if (ptr + size > object->pointer + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100785 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100786 dump_object_info(object);
787 kmem_cache_free(scan_area_cache, area);
788 goto out_unlock;
789 }
790
791 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000792 area->start = ptr;
793 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100794
795 hlist_add_head(&area->node, &object->area_list);
796out_unlock:
797 spin_unlock_irqrestore(&object->lock, flags);
798out:
799 put_object(object);
800}
801
802/*
Catalin Marinas94f4a162017-07-06 15:40:22 -0700803 * Any surplus references (object already gray) to 'ptr' are passed to
804 * 'excess_ref'. This is used in the vmalloc() case where a pointer to
805 * vm_struct may be used as an alternative reference to the vmalloc'ed object
806 * (see free_thread_stack()).
807 */
808static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
809{
810 unsigned long flags;
811 struct kmemleak_object *object;
812
813 object = find_and_get_object(ptr, 0);
814 if (!object) {
815 kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
816 ptr);
817 return;
818 }
819
820 spin_lock_irqsave(&object->lock, flags);
821 object->excess_ref = excess_ref;
822 spin_unlock_irqrestore(&object->lock, flags);
823 put_object(object);
824}
825
826/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100827 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
828 * pointer. Such object will not be scanned by kmemleak but references to it
829 * are searched.
830 */
831static void object_no_scan(unsigned long ptr)
832{
833 unsigned long flags;
834 struct kmemleak_object *object;
835
836 object = find_and_get_object(ptr, 0);
837 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100838 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100839 return;
840 }
841
842 spin_lock_irqsave(&object->lock, flags);
843 object->flags |= OBJECT_NO_SCAN;
844 spin_unlock_irqrestore(&object->lock, flags);
845 put_object(object);
846}
847
848/*
849 * Log an early kmemleak_* call to the early_log buffer. These calls will be
850 * processed later once kmemleak is fully initialized.
851 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100852static void __init log_early(int op_type, const void *ptr, size_t size,
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000853 int min_count)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100854{
855 unsigned long flags;
856 struct early_log *log;
857
Li Zefan8910ae82014-04-03 14:46:29 -0700858 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +0100859 /* kmemleak stopped recording, just count the requests */
860 crt_early_log++;
861 return;
862 }
863
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100864 if (crt_early_log >= ARRAY_SIZE(early_log)) {
Wang Kai21cd3a62015-09-08 15:03:41 -0700865 crt_early_log++;
Catalin Marinasa9d90582009-06-25 10:16:11 +0100866 kmemleak_disable();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100867 return;
868 }
869
870 /*
871 * There is no need for locking since the kernel is still in UP mode
872 * at this stage. Disabling the IRQs is enough.
873 */
874 local_irq_save(flags);
875 log = &early_log[crt_early_log];
876 log->op_type = op_type;
877 log->ptr = ptr;
878 log->size = size;
879 log->min_count = min_count;
Catalin Marinas5f790202011-09-28 12:17:03 +0100880 log->trace_len = __save_stack_trace(log->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100881 crt_early_log++;
882 local_irq_restore(flags);
883}
884
885/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100886 * Log an early allocated block and populate the stack trace.
887 */
888static void early_alloc(struct early_log *log)
889{
890 struct kmemleak_object *object;
891 unsigned long flags;
892 int i;
893
Li Zefan8910ae82014-04-03 14:46:29 -0700894 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
Catalin Marinasfd678962009-08-27 14:29:17 +0100895 return;
896
897 /*
898 * RCU locking needed to ensure object is not freed via put_object().
899 */
900 rcu_read_lock();
901 object = create_object((unsigned long)log->ptr, log->size,
Tetsuo Handac1bcd6b2009-10-09 10:39:24 +0100902 log->min_count, GFP_ATOMIC);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100903 if (!object)
904 goto out;
Catalin Marinasfd678962009-08-27 14:29:17 +0100905 spin_lock_irqsave(&object->lock, flags);
906 for (i = 0; i < log->trace_len; i++)
907 object->trace[i] = log->trace[i];
908 object->trace_len = log->trace_len;
909 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100910out:
Catalin Marinasfd678962009-08-27 14:29:17 +0100911 rcu_read_unlock();
912}
913
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100914/*
915 * Log an early allocated block and populate the stack trace.
916 */
917static void early_alloc_percpu(struct early_log *log)
918{
919 unsigned int cpu;
920 const void __percpu *ptr = log->ptr;
921
922 for_each_possible_cpu(cpu) {
923 log->ptr = per_cpu_ptr(ptr, cpu);
924 early_alloc(log);
925 }
926}
927
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100928/**
929 * kmemleak_alloc - register a newly allocated object
930 * @ptr: pointer to beginning of the object
931 * @size: size of the object
932 * @min_count: minimum number of references to this object. If during memory
933 * scanning a number of references less than @min_count is found,
934 * the object is reported as a memory leak. If @min_count is 0,
935 * the object is never reported as a leak. If @min_count is -1,
936 * the object is ignored (not scanned and not reported as a leak)
937 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
938 *
939 * This function is called from the kernel allocators when a new object
Catalin Marinas94f4a162017-07-06 15:40:22 -0700940 * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100941 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100942void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
943 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100944{
945 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
946
Li Zefan8910ae82014-04-03 14:46:29 -0700947 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100948 create_object((unsigned long)ptr, size, min_count, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700949 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000950 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100951}
952EXPORT_SYMBOL_GPL(kmemleak_alloc);
953
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100954/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100955 * kmemleak_alloc_percpu - register a newly allocated __percpu object
956 * @ptr: __percpu pointer to beginning of the object
957 * @size: size of the object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700958 * @gfp: flags used for kmemleak internal memory allocations
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100959 *
960 * This function is called from the kernel percpu allocator when a new object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700961 * (memory block) is allocated (alloc_percpu).
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100962 */
Larry Finger8a8c35f2015-06-24 16:58:51 -0700963void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
964 gfp_t gfp)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100965{
966 unsigned int cpu;
967
968 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
969
970 /*
971 * Percpu allocations are only scanned and not reported as leaks
972 * (min_count is set to 0).
973 */
Li Zefan8910ae82014-04-03 14:46:29 -0700974 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100975 for_each_possible_cpu(cpu)
976 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
Larry Finger8a8c35f2015-06-24 16:58:51 -0700977 size, 0, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700978 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100979 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
980}
981EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
982
983/**
Catalin Marinas94f4a162017-07-06 15:40:22 -0700984 * kmemleak_vmalloc - register a newly vmalloc'ed object
985 * @area: pointer to vm_struct
986 * @size: size of the object
987 * @gfp: __vmalloc() flags used for kmemleak internal memory allocations
988 *
989 * This function is called from the vmalloc() kernel allocator when a new
990 * object (memory block) is allocated.
991 */
992void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp)
993{
994 pr_debug("%s(0x%p, %zu)\n", __func__, area, size);
995
996 /*
997 * A min_count = 2 is needed because vm_struct contains a reference to
998 * the virtual address of the vmalloc'ed block.
999 */
1000 if (kmemleak_enabled) {
1001 create_object((unsigned long)area->addr, size, 2, gfp);
1002 object_set_excess_ref((unsigned long)area,
1003 (unsigned long)area->addr);
1004 } else if (kmemleak_early_log) {
1005 log_early(KMEMLEAK_ALLOC, area->addr, size, 2);
1006 /* reusing early_log.size for storing area->addr */
1007 log_early(KMEMLEAK_SET_EXCESS_REF,
1008 area, (unsigned long)area->addr, 0);
1009 }
1010}
1011EXPORT_SYMBOL_GPL(kmemleak_vmalloc);
1012
1013/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001014 * kmemleak_free - unregister a previously registered object
1015 * @ptr: pointer to beginning of the object
1016 *
1017 * This function is called from the kernel allocators when an object (memory
1018 * block) is freed (kmem_cache_free, kfree, vfree etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001019 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001020void __ref kmemleak_free(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001021{
1022 pr_debug("%s(0x%p)\n", __func__, ptr);
1023
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001024 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +01001025 delete_object_full((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001026 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001027 log_early(KMEMLEAK_FREE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001028}
1029EXPORT_SYMBOL_GPL(kmemleak_free);
1030
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001031/**
1032 * kmemleak_free_part - partially unregister a previously registered object
1033 * @ptr: pointer to the beginning or inside the object. This also
1034 * represents the start of the range to be freed
1035 * @size: size to be unregistered
1036 *
1037 * This function is called when only a part of a memory block is freed
1038 * (usually from the bootmem allocator).
Catalin Marinas53238a62009-07-07 10:33:00 +01001039 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001040void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +01001041{
1042 pr_debug("%s(0x%p)\n", __func__, ptr);
1043
Li Zefan8910ae82014-04-03 14:46:29 -07001044 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +01001045 delete_object_part((unsigned long)ptr, size);
Li Zefan8910ae82014-04-03 14:46:29 -07001046 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001047 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +01001048}
1049EXPORT_SYMBOL_GPL(kmemleak_free_part);
1050
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001051/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001052 * kmemleak_free_percpu - unregister a previously registered __percpu object
1053 * @ptr: __percpu pointer to beginning of the object
1054 *
1055 * This function is called from the kernel percpu allocator when an object
1056 * (memory block) is freed (free_percpu).
1057 */
1058void __ref kmemleak_free_percpu(const void __percpu *ptr)
1059{
1060 unsigned int cpu;
1061
1062 pr_debug("%s(0x%p)\n", __func__, ptr);
1063
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001064 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001065 for_each_possible_cpu(cpu)
1066 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1067 cpu));
Li Zefan8910ae82014-04-03 14:46:29 -07001068 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001069 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1070}
1071EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1072
1073/**
Catalin Marinasffe2c742014-06-06 14:38:17 -07001074 * kmemleak_update_trace - update object allocation stack trace
1075 * @ptr: pointer to beginning of the object
1076 *
1077 * Override the object allocation stack trace for cases where the actual
1078 * allocation place is not always useful.
1079 */
1080void __ref kmemleak_update_trace(const void *ptr)
1081{
1082 struct kmemleak_object *object;
1083 unsigned long flags;
1084
1085 pr_debug("%s(0x%p)\n", __func__, ptr);
1086
1087 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1088 return;
1089
1090 object = find_and_get_object((unsigned long)ptr, 1);
1091 if (!object) {
1092#ifdef DEBUG
1093 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1094 ptr);
1095#endif
1096 return;
1097 }
1098
1099 spin_lock_irqsave(&object->lock, flags);
1100 object->trace_len = __save_stack_trace(object->trace);
1101 spin_unlock_irqrestore(&object->lock, flags);
1102
1103 put_object(object);
1104}
1105EXPORT_SYMBOL(kmemleak_update_trace);
1106
1107/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001108 * kmemleak_not_leak - mark an allocated object as false positive
1109 * @ptr: pointer to beginning of the object
1110 *
1111 * Calling this function on an object will cause the memory block to no longer
1112 * be reported as leak and always be scanned.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001113 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001114void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001115{
1116 pr_debug("%s(0x%p)\n", __func__, ptr);
1117
Li Zefan8910ae82014-04-03 14:46:29 -07001118 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001119 make_gray_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001120 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001121 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001122}
1123EXPORT_SYMBOL(kmemleak_not_leak);
1124
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001125/**
1126 * kmemleak_ignore - ignore an allocated object
1127 * @ptr: pointer to beginning of the object
1128 *
1129 * Calling this function on an object will cause the memory block to be
1130 * ignored (not scanned and not reported as a leak). This is usually done when
1131 * it is known that the corresponding block is not a leak and does not contain
1132 * any references to other allocated memory blocks.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001133 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001134void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001135{
1136 pr_debug("%s(0x%p)\n", __func__, ptr);
1137
Li Zefan8910ae82014-04-03 14:46:29 -07001138 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001139 make_black_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001140 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001141 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001142}
1143EXPORT_SYMBOL(kmemleak_ignore);
1144
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001145/**
1146 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1147 * @ptr: pointer to beginning or inside the object. This also
1148 * represents the start of the scan area
1149 * @size: size of the scan area
1150 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1151 *
1152 * This function is used when it is known that only certain parts of an object
1153 * contain references to other objects. Kmemleak will only scan these areas
1154 * reducing the number false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001155 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001156void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001157{
1158 pr_debug("%s(0x%p)\n", __func__, ptr);
1159
Li Zefan8910ae82014-04-03 14:46:29 -07001160 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001161 add_scan_area((unsigned long)ptr, size, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -07001162 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001163 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001164}
1165EXPORT_SYMBOL(kmemleak_scan_area);
1166
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001167/**
1168 * kmemleak_no_scan - do not scan an allocated object
1169 * @ptr: pointer to beginning of the object
1170 *
1171 * This function notifies kmemleak not to scan the given memory block. Useful
1172 * in situations where it is known that the given object does not contain any
1173 * references to other objects. Kmemleak will not scan such objects reducing
1174 * the number of false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001175 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001176void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001177{
1178 pr_debug("%s(0x%p)\n", __func__, ptr);
1179
Li Zefan8910ae82014-04-03 14:46:29 -07001180 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001181 object_no_scan((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001182 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001183 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001184}
1185EXPORT_SYMBOL(kmemleak_no_scan);
1186
Catalin Marinas9099dae2016-10-11 13:55:11 -07001187/**
1188 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1189 * address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001190 * @phys: physical address of the object
1191 * @size: size of the object
1192 * @min_count: minimum number of references to this object.
1193 * See kmemleak_alloc()
1194 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
Catalin Marinas9099dae2016-10-11 13:55:11 -07001195 */
1196void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
1197 gfp_t gfp)
1198{
1199 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1200 kmemleak_alloc(__va(phys), size, min_count, gfp);
1201}
1202EXPORT_SYMBOL(kmemleak_alloc_phys);
1203
1204/**
1205 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1206 * physical address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001207 * @phys: physical address if the beginning or inside an object. This
1208 * also represents the start of the range to be freed
1209 * @size: size to be unregistered
Catalin Marinas9099dae2016-10-11 13:55:11 -07001210 */
1211void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1212{
1213 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1214 kmemleak_free_part(__va(phys), size);
1215}
1216EXPORT_SYMBOL(kmemleak_free_part_phys);
1217
1218/**
1219 * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
1220 * address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001221 * @phys: physical address of the object
Catalin Marinas9099dae2016-10-11 13:55:11 -07001222 */
1223void __ref kmemleak_not_leak_phys(phys_addr_t phys)
1224{
1225 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1226 kmemleak_not_leak(__va(phys));
1227}
1228EXPORT_SYMBOL(kmemleak_not_leak_phys);
1229
1230/**
1231 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1232 * address argument
Mike Rapoporte8b098f2018-04-05 16:24:57 -07001233 * @phys: physical address of the object
Catalin Marinas9099dae2016-10-11 13:55:11 -07001234 */
1235void __ref kmemleak_ignore_phys(phys_addr_t phys)
1236{
1237 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1238 kmemleak_ignore(__va(phys));
1239}
1240EXPORT_SYMBOL(kmemleak_ignore_phys);
1241
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001242/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001243 * Update an object's checksum and return true if it was modified.
1244 */
1245static bool update_checksum(struct kmemleak_object *object)
1246{
1247 u32 old_csum = object->checksum;
1248
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001249 kasan_disable_current();
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001250 object->checksum = crc32(0, (void *)object->pointer, object->size);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001251 kasan_enable_current();
1252
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001253 return object->checksum != old_csum;
1254}
1255
1256/*
Catalin Marinas04f70d12017-07-06 15:40:19 -07001257 * Update an object's references. object->lock must be held by the caller.
1258 */
1259static void update_refs(struct kmemleak_object *object)
1260{
1261 if (!color_white(object)) {
1262 /* non-orphan, ignored or new */
1263 return;
1264 }
1265
1266 /*
1267 * Increase the object's reference count (number of pointers to the
1268 * memory block). If this count reaches the required minimum, the
1269 * object's color will become gray and it will be added to the
1270 * gray_list.
1271 */
1272 object->count++;
1273 if (color_gray(object)) {
1274 /* put_object() called when removing from gray_list */
1275 WARN_ON(!get_object(object));
1276 list_add_tail(&object->gray_list, &gray_list);
1277 }
1278}
1279
1280/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001281 * Memory scanning is a long process and it needs to be interruptable. This
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001282 * function checks whether such interrupt condition occurred.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001283 */
1284static int scan_should_stop(void)
1285{
Li Zefan8910ae82014-04-03 14:46:29 -07001286 if (!kmemleak_enabled)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001287 return 1;
1288
1289 /*
1290 * This function may be called from either process or kthread context,
1291 * hence the need to check for both stop conditions.
1292 */
1293 if (current->mm)
1294 return signal_pending(current);
1295 else
1296 return kthread_should_stop();
1297
1298 return 0;
1299}
1300
1301/*
1302 * Scan a memory block (exclusive range) for valid pointers and add those
1303 * found to the gray list.
1304 */
1305static void scan_block(void *_start, void *_end,
Catalin Marinas93ada572015-06-24 16:58:37 -07001306 struct kmemleak_object *scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001307{
1308 unsigned long *ptr;
1309 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1310 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
Catalin Marinas93ada572015-06-24 16:58:37 -07001311 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001312
Catalin Marinas93ada572015-06-24 16:58:37 -07001313 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001314 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001315 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +01001316 unsigned long pointer;
Catalin Marinas94f4a162017-07-06 15:40:22 -07001317 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001318
1319 if (scan_should_stop())
1320 break;
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);
Andrew Morton13ab183d2017-12-14 15:32:31 -08001535 if (!(pfn & 63))
Yisheng Xiebde5f6b2017-11-29 16:11:08 -08001536 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001537 }
1538 }
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001539 put_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001540
1541 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001542 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001543 */
1544 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001545 struct task_struct *p, *g;
1546
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001547 read_lock(&tasklist_lock);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001548 do_each_thread(g, p) {
Catalin Marinas37df49f2016-10-27 17:46:47 -07001549 void *stack = try_get_task_stack(p);
1550 if (stack) {
1551 scan_block(stack, stack + THREAD_SIZE, NULL);
1552 put_task_stack(p);
1553 }
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001554 } while_each_thread(g, p);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001555 read_unlock(&tasklist_lock);
1556 }
1557
1558 /*
1559 * Scan the objects already referenced from the sections scanned
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001560 * above.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001561 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001562 scan_gray_list();
Catalin Marinas25873622009-07-07 10:32:58 +01001563
1564 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001565 * Check for new or unreferenced objects modified since the previous
1566 * scan and color them gray until the next scan.
Catalin Marinas25873622009-07-07 10:32:58 +01001567 */
1568 rcu_read_lock();
1569 list_for_each_entry_rcu(object, &object_list, object_list) {
1570 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001571 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1572 && update_checksum(object) && get_object(object)) {
1573 /* color it gray temporarily */
1574 object->count = object->min_count;
Catalin Marinas25873622009-07-07 10:32:58 +01001575 list_add_tail(&object->gray_list, &gray_list);
1576 }
1577 spin_unlock_irqrestore(&object->lock, flags);
1578 }
1579 rcu_read_unlock();
1580
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001581 /*
1582 * Re-scan the gray list for modified unreferenced objects.
1583 */
1584 scan_gray_list();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001585
1586 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001587 * If scanning was stopped do not report any new unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001588 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001589 if (scan_should_stop())
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001590 return;
1591
1592 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001593 * Scanning result reporting.
1594 */
1595 rcu_read_lock();
1596 list_for_each_entry_rcu(object, &object_list, object_list) {
1597 spin_lock_irqsave(&object->lock, flags);
1598 if (unreferenced_object(object) &&
1599 !(object->flags & OBJECT_REPORTED)) {
1600 object->flags |= OBJECT_REPORTED;
1601 new_leaks++;
1602 }
1603 spin_unlock_irqrestore(&object->lock, flags);
1604 }
1605 rcu_read_unlock();
1606
Li Zefandc9b3f42014-04-03 14:46:26 -07001607 if (new_leaks) {
1608 kmemleak_found_leaks = true;
1609
Joe Perches756a0252016-03-17 14:19:47 -07001610 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1611 new_leaks);
Li Zefandc9b3f42014-04-03 14:46:26 -07001612 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001613
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001614}
1615
1616/*
1617 * Thread function performing automatic memory scanning. Unreferenced objects
1618 * at the end of a memory scan are reported but only the first time.
1619 */
1620static int kmemleak_scan_thread(void *arg)
1621{
1622 static int first_run = 1;
1623
Joe Perchesae281062009-06-23 14:40:26 +01001624 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001625 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001626
1627 /*
1628 * Wait before the first scan to allow the system to fully initialize.
1629 */
1630 if (first_run) {
Vegard Nossum98c42d92016-07-28 15:48:32 -07001631 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001632 first_run = 0;
Vegard Nossum98c42d92016-07-28 15:48:32 -07001633 while (timeout && !kthread_should_stop())
1634 timeout = schedule_timeout_interruptible(timeout);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001635 }
1636
1637 while (!kthread_should_stop()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001638 signed long timeout = jiffies_scan_wait;
1639
1640 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001641 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001642 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001643
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001644 /* wait before the next scan */
1645 while (timeout && !kthread_should_stop())
1646 timeout = schedule_timeout_interruptible(timeout);
1647 }
1648
Joe Perchesae281062009-06-23 14:40:26 +01001649 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001650
1651 return 0;
1652}
1653
1654/*
1655 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001656 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001657 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001658static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001659{
1660 if (scan_thread)
1661 return;
1662 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1663 if (IS_ERR(scan_thread)) {
Joe Perches598d8092016-03-17 14:19:44 -07001664 pr_warn("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001665 scan_thread = NULL;
1666 }
1667}
1668
1669/*
Vinayak Menon914b6df2018-03-28 16:01:16 -07001670 * Stop the automatic memory scanning thread.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001671 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001672static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001673{
1674 if (scan_thread) {
1675 kthread_stop(scan_thread);
1676 scan_thread = NULL;
1677 }
1678}
1679
1680/*
1681 * Iterate over the object_list and return the first valid object at or after
1682 * the required position with its use_count incremented. The function triggers
1683 * a memory scanning when the pos argument points to the first position.
1684 */
1685static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1686{
1687 struct kmemleak_object *object;
1688 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001689 int err;
1690
1691 err = mutex_lock_interruptible(&scan_mutex);
1692 if (err < 0)
1693 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001694
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001695 rcu_read_lock();
1696 list_for_each_entry_rcu(object, &object_list, object_list) {
1697 if (n-- > 0)
1698 continue;
1699 if (get_object(object))
1700 goto out;
1701 }
1702 object = NULL;
1703out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001704 return object;
1705}
1706
1707/*
1708 * Return the next object in the object_list. The function decrements the
1709 * use_count of the previous object and increases that of the next one.
1710 */
1711static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1712{
1713 struct kmemleak_object *prev_obj = v;
1714 struct kmemleak_object *next_obj = NULL;
Michael Wang58fac092012-08-17 12:33:34 +08001715 struct kmemleak_object *obj = prev_obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001716
1717 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001718
Michael Wang58fac092012-08-17 12:33:34 +08001719 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001720 if (get_object(obj)) {
1721 next_obj = obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001722 break;
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001723 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001724 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001725
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001726 put_object(prev_obj);
1727 return next_obj;
1728}
1729
1730/*
1731 * Decrement the use_count of the last object required, if any.
1732 */
1733static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1734{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001735 if (!IS_ERR(v)) {
1736 /*
1737 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1738 * waiting was interrupted, so only release it if !IS_ERR.
1739 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001740 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001741 mutex_unlock(&scan_mutex);
1742 if (v)
1743 put_object(v);
1744 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001745}
1746
1747/*
1748 * Print the information for an unreferenced object to the seq file.
1749 */
1750static int kmemleak_seq_show(struct seq_file *seq, void *v)
1751{
1752 struct kmemleak_object *object = v;
1753 unsigned long flags;
1754
1755 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001756 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001757 print_unreferenced(seq, object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001758 spin_unlock_irqrestore(&object->lock, flags);
1759 return 0;
1760}
1761
1762static const struct seq_operations kmemleak_seq_ops = {
1763 .start = kmemleak_seq_start,
1764 .next = kmemleak_seq_next,
1765 .stop = kmemleak_seq_stop,
1766 .show = kmemleak_seq_show,
1767};
1768
1769static int kmemleak_open(struct inode *inode, struct file *file)
1770{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001771 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001772}
1773
Catalin Marinas189d84e2009-08-27 14:29:15 +01001774static int dump_str_object_info(const char *str)
1775{
1776 unsigned long flags;
1777 struct kmemleak_object *object;
1778 unsigned long addr;
1779
Abhijit Pawardc053732012-12-18 14:23:27 -08001780 if (kstrtoul(str, 0, &addr))
1781 return -EINVAL;
Catalin Marinas189d84e2009-08-27 14:29:15 +01001782 object = find_and_get_object(addr, 0);
1783 if (!object) {
1784 pr_info("Unknown object at 0x%08lx\n", addr);
1785 return -EINVAL;
1786 }
1787
1788 spin_lock_irqsave(&object->lock, flags);
1789 dump_object_info(object);
1790 spin_unlock_irqrestore(&object->lock, flags);
1791
1792 put_object(object);
1793 return 0;
1794}
1795
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001796/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001797 * We use grey instead of black to ensure we can do future scans on the same
1798 * objects. If we did not do future scans these black objects could
1799 * potentially contain references to newly allocated objects in the future and
1800 * we'd end up with false positives.
1801 */
1802static void kmemleak_clear(void)
1803{
1804 struct kmemleak_object *object;
1805 unsigned long flags;
1806
1807 rcu_read_lock();
1808 list_for_each_entry_rcu(object, &object_list, object_list) {
1809 spin_lock_irqsave(&object->lock, flags);
1810 if ((object->flags & OBJECT_REPORTED) &&
1811 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001812 __paint_it(object, KMEMLEAK_GREY);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001813 spin_unlock_irqrestore(&object->lock, flags);
1814 }
1815 rcu_read_unlock();
Li Zefandc9b3f42014-04-03 14:46:26 -07001816
1817 kmemleak_found_leaks = false;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001818}
1819
Li Zefanc89da702014-04-03 14:46:27 -07001820static void __kmemleak_do_cleanup(void);
1821
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001822/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001823 * File write operation to configure kmemleak at run-time. The following
1824 * commands can be written to the /sys/kernel/debug/kmemleak file:
1825 * off - disable kmemleak (irreversible)
1826 * stack=on - enable the task stacks scanning
1827 * stack=off - disable the tasks stacks scanning
1828 * scan=on - start the automatic memory scanning thread
1829 * scan=off - stop the automatic memory scanning thread
1830 * scan=... - set the automatic memory scanning period in seconds (0 to
1831 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001832 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001833 * clear - mark all current reported unreferenced kmemleak objects as
Li Zefanc89da702014-04-03 14:46:27 -07001834 * grey to ignore printing them, or free all kmemleak objects
1835 * if kmemleak has been disabled.
Catalin Marinas189d84e2009-08-27 14:29:15 +01001836 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001837 */
1838static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1839 size_t size, loff_t *ppos)
1840{
1841 char buf[64];
1842 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001843 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001844
1845 buf_size = min(size, (sizeof(buf) - 1));
1846 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1847 return -EFAULT;
1848 buf[buf_size] = 0;
1849
Catalin Marinasb87324d2009-07-07 10:32:58 +01001850 ret = mutex_lock_interruptible(&scan_mutex);
1851 if (ret < 0)
1852 return ret;
1853
Li Zefanc89da702014-04-03 14:46:27 -07001854 if (strncmp(buf, "clear", 5) == 0) {
Li Zefan8910ae82014-04-03 14:46:29 -07001855 if (kmemleak_enabled)
Li Zefanc89da702014-04-03 14:46:27 -07001856 kmemleak_clear();
1857 else
1858 __kmemleak_do_cleanup();
1859 goto out;
1860 }
1861
Li Zefan8910ae82014-04-03 14:46:29 -07001862 if (!kmemleak_enabled) {
Li Zefanc89da702014-04-03 14:46:27 -07001863 ret = -EBUSY;
1864 goto out;
1865 }
1866
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001867 if (strncmp(buf, "off", 3) == 0)
1868 kmemleak_disable();
1869 else if (strncmp(buf, "stack=on", 8) == 0)
1870 kmemleak_stack_scan = 1;
1871 else if (strncmp(buf, "stack=off", 9) == 0)
1872 kmemleak_stack_scan = 0;
1873 else if (strncmp(buf, "scan=on", 7) == 0)
1874 start_scan_thread();
1875 else if (strncmp(buf, "scan=off", 8) == 0)
1876 stop_scan_thread();
1877 else if (strncmp(buf, "scan=", 5) == 0) {
1878 unsigned long secs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001879
Jingoo Han3dbb95f2013-09-11 14:20:25 -07001880 ret = kstrtoul(buf + 5, 0, &secs);
Catalin Marinasb87324d2009-07-07 10:32:58 +01001881 if (ret < 0)
1882 goto out;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001883 stop_scan_thread();
1884 if (secs) {
1885 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1886 start_scan_thread();
1887 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001888 } else if (strncmp(buf, "scan", 4) == 0)
1889 kmemleak_scan();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001890 else if (strncmp(buf, "dump=", 5) == 0)
1891 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001892 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001893 ret = -EINVAL;
1894
1895out:
1896 mutex_unlock(&scan_mutex);
1897 if (ret < 0)
1898 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001899
1900 /* ignore the rest of the buffer, only one command at a time */
1901 *ppos += size;
1902 return size;
1903}
1904
1905static const struct file_operations kmemleak_fops = {
1906 .owner = THIS_MODULE,
1907 .open = kmemleak_open,
1908 .read = seq_read,
1909 .write = kmemleak_write,
1910 .llseek = seq_lseek,
Li Zefan5f3bf192014-04-03 14:46:28 -07001911 .release = seq_release,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001912};
1913
Li Zefanc89da702014-04-03 14:46:27 -07001914static void __kmemleak_do_cleanup(void)
1915{
1916 struct kmemleak_object *object;
1917
1918 rcu_read_lock();
1919 list_for_each_entry_rcu(object, &object_list, object_list)
1920 delete_object_full(object->pointer);
1921 rcu_read_unlock();
1922}
1923
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001924/*
Catalin Marinas74341702011-09-29 11:50:07 +01001925 * Stop the memory scanning thread and free the kmemleak internal objects if
1926 * no previous scan thread (otherwise, kmemleak may still have some useful
1927 * information on memory leaks).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001928 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001929static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001930{
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001931 stop_scan_thread();
1932
Vinayak Menon914b6df2018-03-28 16:01:16 -07001933 mutex_lock(&scan_mutex);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001934 /*
Vinayak Menon914b6df2018-03-28 16:01:16 -07001935 * Once it is made sure that kmemleak_scan has stopped, it is safe to no
1936 * longer track object freeing. Ordering of the scan thread stopping and
1937 * the memory accesses below is guaranteed by the kthread_stop()
1938 * function.
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001939 */
1940 kmemleak_free_enabled = 0;
Vinayak Menon914b6df2018-03-28 16:01:16 -07001941 mutex_unlock(&scan_mutex);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001942
Li Zefanc89da702014-04-03 14:46:27 -07001943 if (!kmemleak_found_leaks)
1944 __kmemleak_do_cleanup();
1945 else
Joe Perches756a0252016-03-17 14:19:47 -07001946 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 +01001947}
1948
Catalin Marinas179a8102009-09-07 10:14:42 +01001949static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001950
1951/*
1952 * Disable kmemleak. No memory allocation/freeing will be traced once this
1953 * function is called. Disabling kmemleak is an irreversible operation.
1954 */
1955static void kmemleak_disable(void)
1956{
1957 /* atomically check whether it was already invoked */
Li Zefan8910ae82014-04-03 14:46:29 -07001958 if (cmpxchg(&kmemleak_error, 0, 1))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001959 return;
1960
1961 /* stop any memory operation tracing */
Li Zefan8910ae82014-04-03 14:46:29 -07001962 kmemleak_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001963
1964 /* check whether it is too early for a kernel thread */
Li Zefan8910ae82014-04-03 14:46:29 -07001965 if (kmemleak_initialized)
Catalin Marinas179a8102009-09-07 10:14:42 +01001966 schedule_work(&cleanup_work);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001967 else
1968 kmemleak_free_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001969
1970 pr_info("Kernel memory leak detector disabled\n");
1971}
1972
1973/*
1974 * Allow boot-time kmemleak disabling (enabled by default).
1975 */
Dou Liyang8bd30c12018-04-05 16:23:46 -07001976static int __init kmemleak_boot_config(char *str)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001977{
1978 if (!str)
1979 return -EINVAL;
1980 if (strcmp(str, "off") == 0)
1981 kmemleak_disable();
Jason Baronab0155a2010-07-19 11:54:17 +01001982 else if (strcmp(str, "on") == 0)
1983 kmemleak_skip_disable = 1;
1984 else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001985 return -EINVAL;
1986 return 0;
1987}
1988early_param("kmemleak", kmemleak_boot_config);
1989
Catalin Marinas5f790202011-09-28 12:17:03 +01001990static void __init print_log_trace(struct early_log *log)
1991{
1992 struct stack_trace trace;
1993
1994 trace.nr_entries = log->trace_len;
1995 trace.entries = log->trace;
1996
1997 pr_notice("Early log backtrace:\n");
1998 print_stack_trace(&trace, 2);
1999}
2000
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002001/*
Catalin Marinas20301172009-06-17 18:29:04 +01002002 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002003 */
2004void __init kmemleak_init(void)
2005{
2006 int i;
2007 unsigned long flags;
2008
Jason Baronab0155a2010-07-19 11:54:17 +01002009#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
2010 if (!kmemleak_skip_disable) {
Catalin Marinas3551a922014-05-09 15:36:59 -07002011 kmemleak_early_log = 0;
Jason Baronab0155a2010-07-19 11:54:17 +01002012 kmemleak_disable();
2013 return;
2014 }
2015#endif
2016
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002017 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
2018 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
2019
2020 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
2021 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002022
Wang Kai21cd3a62015-09-08 15:03:41 -07002023 if (crt_early_log > ARRAY_SIZE(early_log))
Joe Perches598d8092016-03-17 14:19:44 -07002024 pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
2025 crt_early_log);
Catalin Marinasb6693002011-09-28 17:22:56 +01002026
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002027 /* the kernel is still in UP mode, so disabling the IRQs is enough */
2028 local_irq_save(flags);
Catalin Marinas3551a922014-05-09 15:36:59 -07002029 kmemleak_early_log = 0;
Li Zefan8910ae82014-04-03 14:46:29 -07002030 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +01002031 local_irq_restore(flags);
2032 return;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002033 } else {
Li Zefan8910ae82014-04-03 14:46:29 -07002034 kmemleak_enabled = 1;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002035 kmemleak_free_enabled = 1;
2036 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002037 local_irq_restore(flags);
2038
2039 /*
2040 * This is the point where tracking allocations is safe. Automatic
2041 * scanning is started during the late initcall. Add the early logged
2042 * callbacks to the kmemleak infrastructure.
2043 */
2044 for (i = 0; i < crt_early_log; i++) {
2045 struct early_log *log = &early_log[i];
2046
2047 switch (log->op_type) {
2048 case KMEMLEAK_ALLOC:
Catalin Marinasfd678962009-08-27 14:29:17 +01002049 early_alloc(log);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002050 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002051 case KMEMLEAK_ALLOC_PERCPU:
2052 early_alloc_percpu(log);
2053 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002054 case KMEMLEAK_FREE:
2055 kmemleak_free(log->ptr);
2056 break;
Catalin Marinas53238a62009-07-07 10:33:00 +01002057 case KMEMLEAK_FREE_PART:
2058 kmemleak_free_part(log->ptr, log->size);
2059 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002060 case KMEMLEAK_FREE_PERCPU:
2061 kmemleak_free_percpu(log->ptr);
2062 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002063 case KMEMLEAK_NOT_LEAK:
2064 kmemleak_not_leak(log->ptr);
2065 break;
2066 case KMEMLEAK_IGNORE:
2067 kmemleak_ignore(log->ptr);
2068 break;
2069 case KMEMLEAK_SCAN_AREA:
Catalin Marinasc017b4b2009-10-28 13:33:09 +00002070 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002071 break;
2072 case KMEMLEAK_NO_SCAN:
2073 kmemleak_no_scan(log->ptr);
2074 break;
Catalin Marinas94f4a162017-07-06 15:40:22 -07002075 case KMEMLEAK_SET_EXCESS_REF:
2076 object_set_excess_ref((unsigned long)log->ptr,
2077 log->excess_ref);
2078 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002079 default:
Catalin Marinas5f790202011-09-28 12:17:03 +01002080 kmemleak_warn("Unknown early log operation: %d\n",
2081 log->op_type);
2082 }
2083
Li Zefan8910ae82014-04-03 14:46:29 -07002084 if (kmemleak_warning) {
Catalin Marinas5f790202011-09-28 12:17:03 +01002085 print_log_trace(log);
Li Zefan8910ae82014-04-03 14:46:29 -07002086 kmemleak_warning = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002087 }
2088 }
2089}
2090
2091/*
2092 * Late initialization function.
2093 */
2094static int __init kmemleak_late_init(void)
2095{
2096 struct dentry *dentry;
2097
Li Zefan8910ae82014-04-03 14:46:29 -07002098 kmemleak_initialized = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002099
Li Zefan8910ae82014-04-03 14:46:29 -07002100 if (kmemleak_error) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002101 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002102 * Some error occurred and kmemleak was disabled. There is a
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002103 * small chance that kmemleak_disable() was called immediately
2104 * after setting kmemleak_initialized and we may end up with
2105 * two clean-up threads but serialized by scan_mutex.
2106 */
Catalin Marinas179a8102009-09-07 10:14:42 +01002107 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002108 return -ENOMEM;
2109 }
2110
Konstantin Khlebnikov7d6c4df2017-11-15 17:35:30 -08002111 dentry = debugfs_create_file("kmemleak", 0644, NULL, NULL,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002112 &kmemleak_fops);
2113 if (!dentry)
Joe Perches598d8092016-03-17 14:19:44 -07002114 pr_warn("Failed to create the debugfs kmemleak file\n");
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002115 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002116 start_scan_thread();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002117 mutex_unlock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002118
2119 pr_info("Kernel memory leak detector initialized\n");
2120
2121 return 0;
2122}
2123late_initcall(kmemleak_late_init);