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Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001/*
2 * mm/kmemleak.c
3 *
4 * Copyright (C) 2008 ARM Limited
5 * Written by Catalin Marinas <catalin.marinas@arm.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 *
21 * For more information on the algorithm and kmemleak usage, please see
Andreas Platschek22901c62016-12-12 16:42:01 -080022 * Documentation/dev-tools/kmemleak.rst.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010023 *
24 * Notes on locking
25 * ----------------
26 *
27 * The following locks and mutexes are used by kmemleak:
28 *
29 * - kmemleak_lock (rwlock): protects the object_list modifications and
30 * accesses to the object_tree_root. The object_list is the main list
31 * holding the metadata (struct kmemleak_object) for the allocated memory
Michel Lespinasse85d3a312012-10-08 16:31:27 -070032 * blocks. The object_tree_root is a red black tree used to look-up
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010033 * metadata based on a pointer to the corresponding memory block. The
34 * kmemleak_object structures are added to the object_list and
35 * object_tree_root in the create_object() function called from the
36 * kmemleak_alloc() callback and removed in delete_object() called from the
37 * kmemleak_free() callback
38 * - kmemleak_object.lock (spinlock): protects a kmemleak_object. Accesses to
39 * the metadata (e.g. count) are protected by this lock. Note that some
40 * members of this structure may be protected by other means (atomic or
41 * kmemleak_lock). This lock is also held when scanning the corresponding
42 * memory block to avoid the kernel freeing it via the kmemleak_free()
43 * callback. This is less heavyweight than holding a global lock like
44 * kmemleak_lock during scanning
45 * - scan_mutex (mutex): ensures that only one thread may scan the memory for
46 * unreferenced objects at a time. The gray_list contains the objects which
47 * are already referenced or marked as false positives and need to be
48 * scanned. This list is only modified during a scanning episode when the
49 * scan_mutex is held. At the end of a scan, the gray_list is always empty.
50 * Note that the kmemleak_object.use_count is incremented when an object is
Catalin Marinas4698c1f2009-06-26 17:38:27 +010051 * added to the gray_list and therefore cannot be freed. This mutex also
52 * prevents multiple users of the "kmemleak" debugfs file together with
53 * modifications to the memory scanning parameters including the scan_thread
54 * pointer
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010055 *
Catalin Marinas93ada572015-06-24 16:58:37 -070056 * Locks and mutexes are acquired/nested in the following order:
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070057 *
Catalin Marinas93ada572015-06-24 16:58:37 -070058 * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING)
59 *
60 * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex
61 * regions.
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070062 *
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010063 * The kmemleak_object structures have a use_count incremented or decremented
64 * using the get_object()/put_object() functions. When the use_count becomes
65 * 0, this count can no longer be incremented and put_object() schedules the
66 * kmemleak_object freeing via an RCU callback. All calls to the get_object()
67 * function must be protected by rcu_read_lock() to avoid accessing a freed
68 * structure.
69 */
70
Joe Perchesae281062009-06-23 14:40:26 +010071#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
72
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010073#include <linux/init.h>
74#include <linux/kernel.h>
75#include <linux/list.h>
Ingo Molnar3f07c012017-02-08 18:51:30 +010076#include <linux/sched/signal.h>
Ingo Molnar29930022017-02-08 18:51:36 +010077#include <linux/sched/task.h>
Ingo Molnar68db0cf2017-02-08 18:51:37 +010078#include <linux/sched/task_stack.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010079#include <linux/jiffies.h>
80#include <linux/delay.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040081#include <linux/export.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010082#include <linux/kthread.h>
Michel Lespinasse85d3a312012-10-08 16:31:27 -070083#include <linux/rbtree.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010084#include <linux/fs.h>
85#include <linux/debugfs.h>
86#include <linux/seq_file.h>
87#include <linux/cpumask.h>
88#include <linux/spinlock.h>
89#include <linux/mutex.h>
90#include <linux/rcupdate.h>
91#include <linux/stacktrace.h>
92#include <linux/cache.h>
93#include <linux/percpu.h>
94#include <linux/hardirq.h>
Catalin Marinas9099dae2016-10-11 13:55:11 -070095#include <linux/bootmem.h>
96#include <linux/pfn.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010097#include <linux/mmzone.h>
98#include <linux/slab.h>
99#include <linux/thread_info.h>
100#include <linux/err.h>
101#include <linux/uaccess.h>
102#include <linux/string.h>
103#include <linux/nodemask.h>
104#include <linux/mm.h>
Catalin Marinas179a8102009-09-07 10:14:42 +0100105#include <linux/workqueue.h>
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000106#include <linux/crc32.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100107
108#include <asm/sections.h>
109#include <asm/processor.h>
Arun Sharma600634972011-07-26 16:09:06 -0700110#include <linux/atomic.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100111
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -0800112#include <linux/kasan.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100113#include <linux/kmemleak.h>
Laura Abbott029aeff2011-11-15 23:49:09 +0000114#include <linux/memory_hotplug.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100115
116/*
117 * Kmemleak configuration and common defines.
118 */
119#define MAX_TRACE 16 /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100120#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100121#define SECS_FIRST_SCAN 60 /* delay before the first scan */
122#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
Catalin Marinasaf986032009-08-27 14:29:12 +0100123#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100124
125#define BYTES_PER_POINTER sizeof(void *)
126
Catalin Marinas216c04b2009-06-17 18:29:02 +0100127/* GFP bitmask for kmemleak internal allocations */
Vladimir Davydov20b5c302016-01-14 15:18:08 -0800128#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000129 __GFP_NORETRY | __GFP_NOMEMALLOC | \
130 __GFP_NOWARN)
Catalin Marinas216c04b2009-06-17 18:29:02 +0100131
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100132/* scanning area inside a memory block */
133struct kmemleak_scan_area {
134 struct hlist_node node;
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000135 unsigned long start;
136 size_t size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100137};
138
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700139#define KMEMLEAK_GREY 0
140#define KMEMLEAK_BLACK -1
141
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100142/*
143 * Structure holding the metadata for each allocated memory block.
144 * Modifications to such objects should be made while holding the
145 * object->lock. Insertions or deletions from object_list, gray_list or
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700146 * rb_node are already protected by the corresponding locks or mutex (see
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100147 * the notes on locking above). These objects are reference-counted
148 * (use_count) and freed using the RCU mechanism.
149 */
150struct kmemleak_object {
151 spinlock_t lock;
Catalin Marinasf66abf02017-07-06 15:40:16 -0700152 unsigned int flags; /* object status flags */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100153 struct list_head object_list;
154 struct list_head gray_list;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700155 struct rb_node rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100156 struct rcu_head rcu; /* object_list lockless traversal */
157 /* object usage count; object freed when use_count == 0 */
158 atomic_t use_count;
159 unsigned long pointer;
160 size_t size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700161 /* pass surplus references to this pointer */
162 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100163 /* minimum number of a pointers found before it is considered leak */
164 int min_count;
165 /* the total number of pointers found pointing to this object */
166 int count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000167 /* checksum for detecting modified objects */
168 u32 checksum;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100169 /* memory ranges to be scanned inside an object (empty for all) */
170 struct hlist_head area_list;
171 unsigned long trace[MAX_TRACE];
172 unsigned int trace_len;
173 unsigned long jiffies; /* creation timestamp */
174 pid_t pid; /* pid of the current task */
175 char comm[TASK_COMM_LEN]; /* executable name */
176};
177
178/* flag representing the memory block allocation status */
179#define OBJECT_ALLOCATED (1 << 0)
180/* flag set after the first reporting of an unreference object */
181#define OBJECT_REPORTED (1 << 1)
182/* flag set to not scan the object */
183#define OBJECT_NO_SCAN (1 << 2)
184
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100185/* number of bytes to print per line; must be 16 or 32 */
186#define HEX_ROW_SIZE 16
187/* number of bytes to print at a time (1, 2, 4, 8) */
188#define HEX_GROUP_SIZE 1
189/* include ASCII after the hex output */
190#define HEX_ASCII 1
191/* max number of lines to be printed */
192#define HEX_MAX_LINES 2
193
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100194/* the list of all allocated objects */
195static LIST_HEAD(object_list);
196/* the list of gray-colored objects (see color_gray comment below) */
197static LIST_HEAD(gray_list);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700198/* search tree for object boundaries */
199static struct rb_root object_tree_root = RB_ROOT;
200/* rw_lock protecting the access to object_list and object_tree_root */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100201static DEFINE_RWLOCK(kmemleak_lock);
202
203/* allocation caches for kmemleak internal data */
204static struct kmem_cache *object_cache;
205static struct kmem_cache *scan_area_cache;
206
207/* set if tracing memory operations is enabled */
Li Zefan8910ae82014-04-03 14:46:29 -0700208static int kmemleak_enabled;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700209/* same as above but only for the kmemleak_free() callback */
210static int kmemleak_free_enabled;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100211/* set in the late_initcall if there were no errors */
Li Zefan8910ae82014-04-03 14:46:29 -0700212static int kmemleak_initialized;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100213/* enables or disables early logging of the memory operations */
Li Zefan8910ae82014-04-03 14:46:29 -0700214static int kmemleak_early_log = 1;
Catalin Marinas5f790202011-09-28 12:17:03 +0100215/* set if a kmemleak warning was issued */
Li Zefan8910ae82014-04-03 14:46:29 -0700216static int kmemleak_warning;
Catalin Marinas5f790202011-09-28 12:17:03 +0100217/* set if a fatal kmemleak error has occurred */
Li Zefan8910ae82014-04-03 14:46:29 -0700218static int kmemleak_error;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100219
220/* minimum and maximum address that may be valid pointers */
221static unsigned long min_addr = ULONG_MAX;
222static unsigned long max_addr;
223
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100224static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100225/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100226static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100227static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100228/* delay between automatic memory scannings */
229static signed long jiffies_scan_wait;
230/* enables or disables the task stacks scanning */
Catalin Marinase0a2a162009-06-26 17:38:25 +0100231static int kmemleak_stack_scan = 1;
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100232/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100233static DEFINE_MUTEX(scan_mutex);
Jason Baronab0155a2010-07-19 11:54:17 +0100234/* setting kmemleak=on, will set this var, skipping the disable */
235static int kmemleak_skip_disable;
Li Zefandc9b3f42014-04-03 14:46:26 -0700236/* If there are leaks that can be reported */
237static bool kmemleak_found_leaks;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100238
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100239/*
Catalin Marinas20301172009-06-17 18:29:04 +0100240 * Early object allocation/freeing logging. Kmemleak is initialized after the
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100241 * kernel allocator. However, both the kernel allocator and kmemleak may
Catalin Marinas20301172009-06-17 18:29:04 +0100242 * allocate memory blocks which need to be tracked. Kmemleak defines an
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100243 * arbitrary buffer to hold the allocation/freeing information before it is
244 * fully initialized.
245 */
246
247/* kmemleak operation type for early logging */
248enum {
249 KMEMLEAK_ALLOC,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100250 KMEMLEAK_ALLOC_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100251 KMEMLEAK_FREE,
Catalin Marinas53238a62009-07-07 10:33:00 +0100252 KMEMLEAK_FREE_PART,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100253 KMEMLEAK_FREE_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100254 KMEMLEAK_NOT_LEAK,
255 KMEMLEAK_IGNORE,
256 KMEMLEAK_SCAN_AREA,
Catalin Marinas94f4a162017-07-06 15:40:22 -0700257 KMEMLEAK_NO_SCAN,
258 KMEMLEAK_SET_EXCESS_REF
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100259};
260
261/*
262 * Structure holding the information passed to kmemleak callbacks during the
263 * early logging.
264 */
265struct early_log {
266 int op_type; /* kmemleak operation type */
Catalin Marinasf66abf02017-07-06 15:40:16 -0700267 int min_count; /* minimum reference count */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100268 const void *ptr; /* allocated/freed memory block */
Catalin Marinas94f4a162017-07-06 15:40:22 -0700269 union {
270 size_t size; /* memory block size */
271 unsigned long excess_ref; /* surplus reference passing */
272 };
Catalin Marinasfd678962009-08-27 14:29:17 +0100273 unsigned long trace[MAX_TRACE]; /* stack trace */
274 unsigned int trace_len; /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100275};
276
277/* early logging buffer and current position */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100278static struct early_log
279 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
280static int crt_early_log __initdata;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100281
282static void kmemleak_disable(void);
283
284/*
285 * Print a warning and dump the stack trace.
286 */
Catalin Marinas5f790202011-09-28 12:17:03 +0100287#define kmemleak_warn(x...) do { \
Joe Perches598d8092016-03-17 14:19:44 -0700288 pr_warn(x); \
Catalin Marinas5f790202011-09-28 12:17:03 +0100289 dump_stack(); \
Li Zefan8910ae82014-04-03 14:46:29 -0700290 kmemleak_warning = 1; \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100291} while (0)
292
293/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300294 * Macro invoked when a serious kmemleak condition occurred and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100295 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100296 * tracing no longer available.
297 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100298#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100299 kmemleak_warn(x); \
300 kmemleak_disable(); \
301} while (0)
302
303/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100304 * Printing of the objects hex dump to the seq file. The number of lines to be
305 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
306 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
307 * with the object->lock held.
308 */
309static void hex_dump_object(struct seq_file *seq,
310 struct kmemleak_object *object)
311{
312 const u8 *ptr = (const u8 *)object->pointer;
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700313 size_t len;
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100314
315 /* limit the number of lines to HEX_MAX_LINES */
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700316 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100317
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700318 seq_printf(seq, " hex dump (first %zu bytes):\n", len);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700319 kasan_disable_current();
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700320 seq_hex_dump(seq, " ", DUMP_PREFIX_NONE, HEX_ROW_SIZE,
321 HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700322 kasan_enable_current();
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100323}
324
325/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100326 * Object colors, encoded with count and min_count:
327 * - white - orphan object, not enough references to it (count < min_count)
328 * - gray - not orphan, not marked as false positive (min_count == 0) or
329 * sufficient references to it (count >= min_count)
330 * - black - ignore, it doesn't contain references (e.g. text section)
331 * (min_count == -1). No function defined for this color.
332 * Newly created objects don't have any color assigned (object->count == -1)
333 * before the next memory scan when they become white.
334 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100335static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100336{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700337 return object->count != KMEMLEAK_BLACK &&
338 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100339}
340
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100341static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100342{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700343 return object->min_count != KMEMLEAK_BLACK &&
344 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100345}
346
347/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100348 * Objects are considered unreferenced only if their color is white, they have
349 * not be deleted and have a minimum age to avoid false positives caused by
350 * pointers temporarily stored in CPU registers.
351 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100352static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100353{
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000354 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100355 time_before_eq(object->jiffies + jiffies_min_age,
356 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100357}
358
359/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100360 * Printing of the unreferenced objects information to the seq file. The
361 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100362 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100363static void print_unreferenced(struct seq_file *seq,
364 struct kmemleak_object *object)
365{
366 int i;
Catalin Marinasfefdd332009-10-28 13:33:12 +0000367 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100368
Catalin Marinasbab4a342009-06-26 17:38:26 +0100369 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
370 object->pointer, object->size);
Catalin Marinasfefdd332009-10-28 13:33:12 +0000371 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
372 object->comm, object->pid, object->jiffies,
373 msecs_age / 1000, msecs_age % 1000);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100374 hex_dump_object(seq, object);
Catalin Marinasbab4a342009-06-26 17:38:26 +0100375 seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100376
377 for (i = 0; i < object->trace_len; i++) {
378 void *ptr = (void *)object->trace[i];
Catalin Marinasbab4a342009-06-26 17:38:26 +0100379 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100380 }
381}
382
383/*
384 * Print the kmemleak_object information. This function is used mainly for
385 * debugging special cases when kmemleak operations. It must be called with
386 * the object->lock held.
387 */
388static void dump_object_info(struct kmemleak_object *object)
389{
390 struct stack_trace trace;
391
392 trace.nr_entries = object->trace_len;
393 trace.entries = object->trace;
394
Joe Perchesae281062009-06-23 14:40:26 +0100395 pr_notice("Object 0x%08lx (size %zu):\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700396 object->pointer, object->size);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100397 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
398 object->comm, object->pid, object->jiffies);
399 pr_notice(" min_count = %d\n", object->min_count);
400 pr_notice(" count = %d\n", object->count);
Catalin Marinasf66abf02017-07-06 15:40:16 -0700401 pr_notice(" flags = 0x%x\n", object->flags);
Jianpeng Maaae0ad72014-06-06 14:38:16 -0700402 pr_notice(" checksum = %u\n", object->checksum);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100403 pr_notice(" backtrace:\n");
404 print_stack_trace(&trace, 4);
405}
406
407/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700408 * Look-up a memory block metadata (kmemleak_object) in the object search
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100409 * tree based on a pointer value. If alias is 0, only values pointing to the
410 * beginning of the memory block are allowed. The kmemleak_lock must be held
411 * when calling this function.
412 */
413static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
414{
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700415 struct rb_node *rb = object_tree_root.rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100416
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700417 while (rb) {
418 struct kmemleak_object *object =
419 rb_entry(rb, struct kmemleak_object, rb_node);
420 if (ptr < object->pointer)
421 rb = object->rb_node.rb_left;
422 else if (object->pointer + object->size <= ptr)
423 rb = object->rb_node.rb_right;
424 else if (object->pointer == ptr || alias)
425 return object;
426 else {
Catalin Marinas5f790202011-09-28 12:17:03 +0100427 kmemleak_warn("Found object by alias at 0x%08lx\n",
428 ptr);
Catalin Marinasa7686a42010-07-19 11:54:16 +0100429 dump_object_info(object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700430 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100431 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700432 }
433 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100434}
435
436/*
437 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
438 * that once an object's use_count reached 0, the RCU freeing was already
439 * registered and the object should no longer be used. This function must be
440 * called under the protection of rcu_read_lock().
441 */
442static int get_object(struct kmemleak_object *object)
443{
444 return atomic_inc_not_zero(&object->use_count);
445}
446
447/*
448 * RCU callback to free a kmemleak_object.
449 */
450static void free_object_rcu(struct rcu_head *rcu)
451{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800452 struct hlist_node *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100453 struct kmemleak_scan_area *area;
454 struct kmemleak_object *object =
455 container_of(rcu, struct kmemleak_object, rcu);
456
457 /*
458 * Once use_count is 0 (guaranteed by put_object), there is no other
459 * code accessing this object, hence no need for locking.
460 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800461 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
462 hlist_del(&area->node);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100463 kmem_cache_free(scan_area_cache, area);
464 }
465 kmem_cache_free(object_cache, object);
466}
467
468/*
469 * Decrement the object use_count. Once the count is 0, free the object using
470 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
471 * delete_object() path, the delayed RCU freeing ensures that there is no
472 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
473 * is also possible.
474 */
475static void put_object(struct kmemleak_object *object)
476{
477 if (!atomic_dec_and_test(&object->use_count))
478 return;
479
480 /* should only get here after delete_object was called */
481 WARN_ON(object->flags & OBJECT_ALLOCATED);
482
483 call_rcu(&object->rcu, free_object_rcu);
484}
485
486/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700487 * Look up an object in the object search tree and increase its use_count.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100488 */
489static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
490{
491 unsigned long flags;
Alexey Klimov9fbed252015-11-05 18:45:57 -0800492 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100493
494 rcu_read_lock();
495 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -0700496 object = lookup_object(ptr, alias);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100497 read_unlock_irqrestore(&kmemleak_lock, flags);
498
499 /* check whether the object is still available */
500 if (object && !get_object(object))
501 object = NULL;
502 rcu_read_unlock();
503
504 return object;
505}
506
507/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700508 * Look up an object in the object search tree and remove it from both
509 * object_tree_root and object_list. The returned object's use_count should be
510 * at least 1, as initially set by create_object().
511 */
512static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
513{
514 unsigned long flags;
515 struct kmemleak_object *object;
516
517 write_lock_irqsave(&kmemleak_lock, flags);
518 object = lookup_object(ptr, alias);
519 if (object) {
520 rb_erase(&object->rb_node, &object_tree_root);
521 list_del_rcu(&object->object_list);
522 }
523 write_unlock_irqrestore(&kmemleak_lock, flags);
524
525 return object;
526}
527
528/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100529 * Save stack trace to the given array of MAX_TRACE size.
530 */
531static int __save_stack_trace(unsigned long *trace)
532{
533 struct stack_trace stack_trace;
534
535 stack_trace.max_entries = MAX_TRACE;
536 stack_trace.nr_entries = 0;
537 stack_trace.entries = trace;
538 stack_trace.skip = 2;
539 save_stack_trace(&stack_trace);
540
541 return stack_trace.nr_entries;
542}
543
544/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100545 * Create the metadata (struct kmemleak_object) corresponding to an allocated
546 * memory block and add it to the object_list and object_tree_root.
547 */
Catalin Marinasfd678962009-08-27 14:29:17 +0100548static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
549 int min_count, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100550{
551 unsigned long flags;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700552 struct kmemleak_object *object, *parent;
553 struct rb_node **link, *rb_parent;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100554
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000555 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100556 if (!object) {
Joe Perches598d8092016-03-17 14:19:44 -0700557 pr_warn("Cannot allocate a kmemleak_object structure\n");
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000558 kmemleak_disable();
Catalin Marinasfd678962009-08-27 14:29:17 +0100559 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100560 }
561
562 INIT_LIST_HEAD(&object->object_list);
563 INIT_LIST_HEAD(&object->gray_list);
564 INIT_HLIST_HEAD(&object->area_list);
565 spin_lock_init(&object->lock);
566 atomic_set(&object->use_count, 1);
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000567 object->flags = OBJECT_ALLOCATED;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100568 object->pointer = ptr;
569 object->size = size;
Catalin Marinas94f4a162017-07-06 15:40:22 -0700570 object->excess_ref = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100571 object->min_count = min_count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000572 object->count = 0; /* white color initially */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100573 object->jiffies = jiffies;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000574 object->checksum = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100575
576 /* task information */
577 if (in_irq()) {
578 object->pid = 0;
579 strncpy(object->comm, "hardirq", sizeof(object->comm));
580 } else if (in_softirq()) {
581 object->pid = 0;
582 strncpy(object->comm, "softirq", sizeof(object->comm));
583 } else {
584 object->pid = current->pid;
585 /*
586 * There is a small chance of a race with set_task_comm(),
587 * however using get_task_comm() here may cause locking
588 * dependency issues with current->alloc_lock. In the worst
589 * case, the command line is not correct.
590 */
591 strncpy(object->comm, current->comm, sizeof(object->comm));
592 }
593
594 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100595 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100596
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100597 write_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100598
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100599 min_addr = min(min_addr, ptr);
600 max_addr = max(max_addr, ptr + size);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700601 link = &object_tree_root.rb_node;
602 rb_parent = NULL;
603 while (*link) {
604 rb_parent = *link;
605 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
606 if (ptr + size <= parent->pointer)
607 link = &parent->rb_node.rb_left;
608 else if (parent->pointer + parent->size <= ptr)
609 link = &parent->rb_node.rb_right;
610 else {
Joe Perches756a0252016-03-17 14:19:47 -0700611 kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700612 ptr);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700613 /*
614 * No need for parent->lock here since "parent" cannot
615 * be freed while the kmemleak_lock is held.
616 */
617 dump_object_info(parent);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700618 kmem_cache_free(object_cache, object);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700619 object = NULL;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700620 goto out;
621 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100622 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700623 rb_link_node(&object->rb_node, rb_parent, link);
624 rb_insert_color(&object->rb_node, &object_tree_root);
625
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100626 list_add_tail_rcu(&object->object_list, &object_list);
627out:
628 write_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinasfd678962009-08-27 14:29:17 +0100629 return object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100630}
631
632/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700633 * Mark the object as not allocated and schedule RCU freeing via put_object().
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100634 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100635static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100636{
637 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100638
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100639 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinase781a9a2015-06-24 16:58:29 -0700640 WARN_ON(atomic_read(&object->use_count) < 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100641
642 /*
643 * Locking here also ensures that the corresponding memory block
644 * cannot be freed when it is being scanned.
645 */
646 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100647 object->flags &= ~OBJECT_ALLOCATED;
648 spin_unlock_irqrestore(&object->lock, flags);
649 put_object(object);
650}
651
652/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100653 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
654 * delete it.
655 */
656static void delete_object_full(unsigned long ptr)
657{
658 struct kmemleak_object *object;
659
Catalin Marinase781a9a2015-06-24 16:58:29 -0700660 object = find_and_remove_object(ptr, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100661 if (!object) {
662#ifdef DEBUG
663 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
664 ptr);
665#endif
666 return;
667 }
668 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100669}
670
671/*
672 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
673 * delete it. If the memory block is partially freed, the function may create
674 * additional metadata for the remaining parts of the block.
675 */
676static void delete_object_part(unsigned long ptr, size_t size)
677{
678 struct kmemleak_object *object;
679 unsigned long start, end;
680
Catalin Marinase781a9a2015-06-24 16:58:29 -0700681 object = find_and_remove_object(ptr, 1);
Catalin Marinas53238a62009-07-07 10:33:00 +0100682 if (!object) {
683#ifdef DEBUG
Joe Perches756a0252016-03-17 14:19:47 -0700684 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
685 ptr, size);
Catalin Marinas53238a62009-07-07 10:33:00 +0100686#endif
687 return;
688 }
Catalin Marinas53238a62009-07-07 10:33:00 +0100689
690 /*
691 * Create one or two objects that may result from the memory block
692 * split. Note that partial freeing is only done by free_bootmem() and
693 * this happens before kmemleak_init() is called. The path below is
694 * only executed during early log recording in kmemleak_init(), so
695 * GFP_KERNEL is enough.
696 */
697 start = object->pointer;
698 end = object->pointer + object->size;
699 if (ptr > start)
700 create_object(start, ptr - start, object->min_count,
701 GFP_KERNEL);
702 if (ptr + size < end)
703 create_object(ptr + size, end - ptr - size, object->min_count,
704 GFP_KERNEL);
705
Catalin Marinase781a9a2015-06-24 16:58:29 -0700706 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100707}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700708
709static void __paint_it(struct kmemleak_object *object, int color)
710{
711 object->min_count = color;
712 if (color == KMEMLEAK_BLACK)
713 object->flags |= OBJECT_NO_SCAN;
714}
715
716static void paint_it(struct kmemleak_object *object, int color)
717{
718 unsigned long flags;
719
720 spin_lock_irqsave(&object->lock, flags);
721 __paint_it(object, color);
722 spin_unlock_irqrestore(&object->lock, flags);
723}
724
725static void paint_ptr(unsigned long ptr, int color)
726{
727 struct kmemleak_object *object;
728
729 object = find_and_get_object(ptr, 0);
730 if (!object) {
Joe Perches756a0252016-03-17 14:19:47 -0700731 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
732 ptr,
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700733 (color == KMEMLEAK_GREY) ? "Grey" :
734 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
735 return;
736 }
737 paint_it(object, color);
738 put_object(object);
739}
740
Catalin Marinas53238a62009-07-07 10:33:00 +0100741/*
Holger Hans Peter Freyther145b64b2010-07-22 19:54:13 +0800742 * Mark an object permanently as gray-colored so that it can no longer be
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100743 * reported as a leak. This is used in general to mark a false positive.
744 */
745static void make_gray_object(unsigned long ptr)
746{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700747 paint_ptr(ptr, KMEMLEAK_GREY);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100748}
749
750/*
751 * Mark the object as black-colored so that it is ignored from scans and
752 * reporting.
753 */
754static void make_black_object(unsigned long ptr)
755{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700756 paint_ptr(ptr, KMEMLEAK_BLACK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100757}
758
759/*
760 * Add a scanning area to the object. If at least one such area is added,
761 * kmemleak will only scan these ranges rather than the whole memory block.
762 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000763static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100764{
765 unsigned long flags;
766 struct kmemleak_object *object;
767 struct kmemleak_scan_area *area;
768
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000769 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100770 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100771 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
772 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100773 return;
774 }
775
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000776 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100777 if (!area) {
Joe Perches598d8092016-03-17 14:19:44 -0700778 pr_warn("Cannot allocate a scan area\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100779 goto out;
780 }
781
782 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas7f88f882013-11-12 15:07:45 -0800783 if (size == SIZE_MAX) {
784 size = object->pointer + object->size - ptr;
785 } else if (ptr + size > object->pointer + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100786 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100787 dump_object_info(object);
788 kmem_cache_free(scan_area_cache, area);
789 goto out_unlock;
790 }
791
792 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000793 area->start = ptr;
794 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100795
796 hlist_add_head(&area->node, &object->area_list);
797out_unlock:
798 spin_unlock_irqrestore(&object->lock, flags);
799out:
800 put_object(object);
801}
802
803/*
Catalin Marinas94f4a162017-07-06 15:40:22 -0700804 * Any surplus references (object already gray) to 'ptr' are passed to
805 * 'excess_ref'. This is used in the vmalloc() case where a pointer to
806 * vm_struct may be used as an alternative reference to the vmalloc'ed object
807 * (see free_thread_stack()).
808 */
809static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
810{
811 unsigned long flags;
812 struct kmemleak_object *object;
813
814 object = find_and_get_object(ptr, 0);
815 if (!object) {
816 kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
817 ptr);
818 return;
819 }
820
821 spin_lock_irqsave(&object->lock, flags);
822 object->excess_ref = excess_ref;
823 spin_unlock_irqrestore(&object->lock, flags);
824 put_object(object);
825}
826
827/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100828 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
829 * pointer. Such object will not be scanned by kmemleak but references to it
830 * are searched.
831 */
832static void object_no_scan(unsigned long ptr)
833{
834 unsigned long flags;
835 struct kmemleak_object *object;
836
837 object = find_and_get_object(ptr, 0);
838 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100839 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100840 return;
841 }
842
843 spin_lock_irqsave(&object->lock, flags);
844 object->flags |= OBJECT_NO_SCAN;
845 spin_unlock_irqrestore(&object->lock, flags);
846 put_object(object);
847}
848
849/*
850 * Log an early kmemleak_* call to the early_log buffer. These calls will be
851 * processed later once kmemleak is fully initialized.
852 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100853static void __init log_early(int op_type, const void *ptr, size_t size,
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000854 int min_count)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100855{
856 unsigned long flags;
857 struct early_log *log;
858
Li Zefan8910ae82014-04-03 14:46:29 -0700859 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +0100860 /* kmemleak stopped recording, just count the requests */
861 crt_early_log++;
862 return;
863 }
864
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100865 if (crt_early_log >= ARRAY_SIZE(early_log)) {
Wang Kai21cd3a62015-09-08 15:03:41 -0700866 crt_early_log++;
Catalin Marinasa9d90582009-06-25 10:16:11 +0100867 kmemleak_disable();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100868 return;
869 }
870
871 /*
872 * There is no need for locking since the kernel is still in UP mode
873 * at this stage. Disabling the IRQs is enough.
874 */
875 local_irq_save(flags);
876 log = &early_log[crt_early_log];
877 log->op_type = op_type;
878 log->ptr = ptr;
879 log->size = size;
880 log->min_count = min_count;
Catalin Marinas5f790202011-09-28 12:17:03 +0100881 log->trace_len = __save_stack_trace(log->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100882 crt_early_log++;
883 local_irq_restore(flags);
884}
885
886/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100887 * Log an early allocated block and populate the stack trace.
888 */
889static void early_alloc(struct early_log *log)
890{
891 struct kmemleak_object *object;
892 unsigned long flags;
893 int i;
894
Li Zefan8910ae82014-04-03 14:46:29 -0700895 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
Catalin Marinasfd678962009-08-27 14:29:17 +0100896 return;
897
898 /*
899 * RCU locking needed to ensure object is not freed via put_object().
900 */
901 rcu_read_lock();
902 object = create_object((unsigned long)log->ptr, log->size,
Tetsuo Handac1bcd6b2009-10-09 10:39:24 +0100903 log->min_count, GFP_ATOMIC);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100904 if (!object)
905 goto out;
Catalin Marinasfd678962009-08-27 14:29:17 +0100906 spin_lock_irqsave(&object->lock, flags);
907 for (i = 0; i < log->trace_len; i++)
908 object->trace[i] = log->trace[i];
909 object->trace_len = log->trace_len;
910 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100911out:
Catalin Marinasfd678962009-08-27 14:29:17 +0100912 rcu_read_unlock();
913}
914
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100915/*
916 * Log an early allocated block and populate the stack trace.
917 */
918static void early_alloc_percpu(struct early_log *log)
919{
920 unsigned int cpu;
921 const void __percpu *ptr = log->ptr;
922
923 for_each_possible_cpu(cpu) {
924 log->ptr = per_cpu_ptr(ptr, cpu);
925 early_alloc(log);
926 }
927}
928
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100929/**
930 * kmemleak_alloc - register a newly allocated object
931 * @ptr: pointer to beginning of the object
932 * @size: size of the object
933 * @min_count: minimum number of references to this object. If during memory
934 * scanning a number of references less than @min_count is found,
935 * the object is reported as a memory leak. If @min_count is 0,
936 * the object is never reported as a leak. If @min_count is -1,
937 * the object is ignored (not scanned and not reported as a leak)
938 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
939 *
940 * This function is called from the kernel allocators when a new object
Catalin Marinas94f4a162017-07-06 15:40:22 -0700941 * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100942 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100943void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
944 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100945{
946 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
947
Li Zefan8910ae82014-04-03 14:46:29 -0700948 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100949 create_object((unsigned long)ptr, size, min_count, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700950 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000951 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100952}
953EXPORT_SYMBOL_GPL(kmemleak_alloc);
954
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100955/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100956 * kmemleak_alloc_percpu - register a newly allocated __percpu object
957 * @ptr: __percpu pointer to beginning of the object
958 * @size: size of the object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700959 * @gfp: flags used for kmemleak internal memory allocations
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100960 *
961 * This function is called from the kernel percpu allocator when a new object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700962 * (memory block) is allocated (alloc_percpu).
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100963 */
Larry Finger8a8c35f2015-06-24 16:58:51 -0700964void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
965 gfp_t gfp)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100966{
967 unsigned int cpu;
968
969 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
970
971 /*
972 * Percpu allocations are only scanned and not reported as leaks
973 * (min_count is set to 0).
974 */
Li Zefan8910ae82014-04-03 14:46:29 -0700975 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100976 for_each_possible_cpu(cpu)
977 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
Larry Finger8a8c35f2015-06-24 16:58:51 -0700978 size, 0, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700979 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100980 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
981}
982EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
983
984/**
Catalin Marinas94f4a162017-07-06 15:40:22 -0700985 * kmemleak_vmalloc - register a newly vmalloc'ed object
986 * @area: pointer to vm_struct
987 * @size: size of the object
988 * @gfp: __vmalloc() flags used for kmemleak internal memory allocations
989 *
990 * This function is called from the vmalloc() kernel allocator when a new
991 * object (memory block) is allocated.
992 */
993void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp)
994{
995 pr_debug("%s(0x%p, %zu)\n", __func__, area, size);
996
997 /*
998 * A min_count = 2 is needed because vm_struct contains a reference to
999 * the virtual address of the vmalloc'ed block.
1000 */
1001 if (kmemleak_enabled) {
1002 create_object((unsigned long)area->addr, size, 2, gfp);
1003 object_set_excess_ref((unsigned long)area,
1004 (unsigned long)area->addr);
1005 } else if (kmemleak_early_log) {
1006 log_early(KMEMLEAK_ALLOC, area->addr, size, 2);
1007 /* reusing early_log.size for storing area->addr */
1008 log_early(KMEMLEAK_SET_EXCESS_REF,
1009 area, (unsigned long)area->addr, 0);
1010 }
1011}
1012EXPORT_SYMBOL_GPL(kmemleak_vmalloc);
1013
1014/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001015 * kmemleak_free - unregister a previously registered object
1016 * @ptr: pointer to beginning of the object
1017 *
1018 * This function is called from the kernel allocators when an object (memory
1019 * block) is freed (kmem_cache_free, kfree, vfree etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001020 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001021void __ref kmemleak_free(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001022{
1023 pr_debug("%s(0x%p)\n", __func__, ptr);
1024
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001025 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +01001026 delete_object_full((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001027 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001028 log_early(KMEMLEAK_FREE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001029}
1030EXPORT_SYMBOL_GPL(kmemleak_free);
1031
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001032/**
1033 * kmemleak_free_part - partially unregister a previously registered object
1034 * @ptr: pointer to the beginning or inside the object. This also
1035 * represents the start of the range to be freed
1036 * @size: size to be unregistered
1037 *
1038 * This function is called when only a part of a memory block is freed
1039 * (usually from the bootmem allocator).
Catalin Marinas53238a62009-07-07 10:33:00 +01001040 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001041void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +01001042{
1043 pr_debug("%s(0x%p)\n", __func__, ptr);
1044
Li Zefan8910ae82014-04-03 14:46:29 -07001045 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +01001046 delete_object_part((unsigned long)ptr, size);
Li Zefan8910ae82014-04-03 14:46:29 -07001047 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001048 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +01001049}
1050EXPORT_SYMBOL_GPL(kmemleak_free_part);
1051
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001052/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001053 * kmemleak_free_percpu - unregister a previously registered __percpu object
1054 * @ptr: __percpu pointer to beginning of the object
1055 *
1056 * This function is called from the kernel percpu allocator when an object
1057 * (memory block) is freed (free_percpu).
1058 */
1059void __ref kmemleak_free_percpu(const void __percpu *ptr)
1060{
1061 unsigned int cpu;
1062
1063 pr_debug("%s(0x%p)\n", __func__, ptr);
1064
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001065 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001066 for_each_possible_cpu(cpu)
1067 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1068 cpu));
Li Zefan8910ae82014-04-03 14:46:29 -07001069 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001070 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1071}
1072EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1073
1074/**
Catalin Marinasffe2c742014-06-06 14:38:17 -07001075 * kmemleak_update_trace - update object allocation stack trace
1076 * @ptr: pointer to beginning of the object
1077 *
1078 * Override the object allocation stack trace for cases where the actual
1079 * allocation place is not always useful.
1080 */
1081void __ref kmemleak_update_trace(const void *ptr)
1082{
1083 struct kmemleak_object *object;
1084 unsigned long flags;
1085
1086 pr_debug("%s(0x%p)\n", __func__, ptr);
1087
1088 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1089 return;
1090
1091 object = find_and_get_object((unsigned long)ptr, 1);
1092 if (!object) {
1093#ifdef DEBUG
1094 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1095 ptr);
1096#endif
1097 return;
1098 }
1099
1100 spin_lock_irqsave(&object->lock, flags);
1101 object->trace_len = __save_stack_trace(object->trace);
1102 spin_unlock_irqrestore(&object->lock, flags);
1103
1104 put_object(object);
1105}
1106EXPORT_SYMBOL(kmemleak_update_trace);
1107
1108/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001109 * kmemleak_not_leak - mark an allocated object as false positive
1110 * @ptr: pointer to beginning of the object
1111 *
1112 * Calling this function on an object will cause the memory block to no longer
1113 * be reported as leak and always be scanned.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001114 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001115void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001116{
1117 pr_debug("%s(0x%p)\n", __func__, ptr);
1118
Li Zefan8910ae82014-04-03 14:46:29 -07001119 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001120 make_gray_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001121 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001122 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001123}
1124EXPORT_SYMBOL(kmemleak_not_leak);
1125
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001126/**
1127 * kmemleak_ignore - ignore an allocated object
1128 * @ptr: pointer to beginning of the object
1129 *
1130 * Calling this function on an object will cause the memory block to be
1131 * ignored (not scanned and not reported as a leak). This is usually done when
1132 * it is known that the corresponding block is not a leak and does not contain
1133 * any references to other allocated memory blocks.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001134 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001135void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001136{
1137 pr_debug("%s(0x%p)\n", __func__, ptr);
1138
Li Zefan8910ae82014-04-03 14:46:29 -07001139 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001140 make_black_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001141 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001142 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001143}
1144EXPORT_SYMBOL(kmemleak_ignore);
1145
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001146/**
1147 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1148 * @ptr: pointer to beginning or inside the object. This also
1149 * represents the start of the scan area
1150 * @size: size of the scan area
1151 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1152 *
1153 * This function is used when it is known that only certain parts of an object
1154 * contain references to other objects. Kmemleak will only scan these areas
1155 * reducing the number false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001156 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001157void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001158{
1159 pr_debug("%s(0x%p)\n", __func__, ptr);
1160
Li Zefan8910ae82014-04-03 14:46:29 -07001161 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001162 add_scan_area((unsigned long)ptr, size, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -07001163 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001164 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001165}
1166EXPORT_SYMBOL(kmemleak_scan_area);
1167
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001168/**
1169 * kmemleak_no_scan - do not scan an allocated object
1170 * @ptr: pointer to beginning of the object
1171 *
1172 * This function notifies kmemleak not to scan the given memory block. Useful
1173 * in situations where it is known that the given object does not contain any
1174 * references to other objects. Kmemleak will not scan such objects reducing
1175 * the number of false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001176 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001177void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001178{
1179 pr_debug("%s(0x%p)\n", __func__, ptr);
1180
Li Zefan8910ae82014-04-03 14:46:29 -07001181 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001182 object_no_scan((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001183 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001184 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001185}
1186EXPORT_SYMBOL(kmemleak_no_scan);
1187
Catalin Marinas9099dae2016-10-11 13:55:11 -07001188/**
1189 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1190 * address argument
1191 */
1192void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
1193 gfp_t gfp)
1194{
1195 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1196 kmemleak_alloc(__va(phys), size, min_count, gfp);
1197}
1198EXPORT_SYMBOL(kmemleak_alloc_phys);
1199
1200/**
1201 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1202 * physical address argument
1203 */
1204void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1205{
1206 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1207 kmemleak_free_part(__va(phys), size);
1208}
1209EXPORT_SYMBOL(kmemleak_free_part_phys);
1210
1211/**
1212 * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
1213 * address argument
1214 */
1215void __ref kmemleak_not_leak_phys(phys_addr_t phys)
1216{
1217 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1218 kmemleak_not_leak(__va(phys));
1219}
1220EXPORT_SYMBOL(kmemleak_not_leak_phys);
1221
1222/**
1223 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1224 * address argument
1225 */
1226void __ref kmemleak_ignore_phys(phys_addr_t phys)
1227{
1228 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1229 kmemleak_ignore(__va(phys));
1230}
1231EXPORT_SYMBOL(kmemleak_ignore_phys);
1232
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001233/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001234 * Update an object's checksum and return true if it was modified.
1235 */
1236static bool update_checksum(struct kmemleak_object *object)
1237{
1238 u32 old_csum = object->checksum;
1239
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001240 kasan_disable_current();
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001241 object->checksum = crc32(0, (void *)object->pointer, object->size);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001242 kasan_enable_current();
1243
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001244 return object->checksum != old_csum;
1245}
1246
1247/*
Catalin Marinas04f70d12017-07-06 15:40:19 -07001248 * Update an object's references. object->lock must be held by the caller.
1249 */
1250static void update_refs(struct kmemleak_object *object)
1251{
1252 if (!color_white(object)) {
1253 /* non-orphan, ignored or new */
1254 return;
1255 }
1256
1257 /*
1258 * Increase the object's reference count (number of pointers to the
1259 * memory block). If this count reaches the required minimum, the
1260 * object's color will become gray and it will be added to the
1261 * gray_list.
1262 */
1263 object->count++;
1264 if (color_gray(object)) {
1265 /* put_object() called when removing from gray_list */
1266 WARN_ON(!get_object(object));
1267 list_add_tail(&object->gray_list, &gray_list);
1268 }
1269}
1270
1271/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001272 * Memory scanning is a long process and it needs to be interruptable. This
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001273 * function checks whether such interrupt condition occurred.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001274 */
1275static int scan_should_stop(void)
1276{
Li Zefan8910ae82014-04-03 14:46:29 -07001277 if (!kmemleak_enabled)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001278 return 1;
1279
1280 /*
1281 * This function may be called from either process or kthread context,
1282 * hence the need to check for both stop conditions.
1283 */
1284 if (current->mm)
1285 return signal_pending(current);
1286 else
1287 return kthread_should_stop();
1288
1289 return 0;
1290}
1291
1292/*
1293 * Scan a memory block (exclusive range) for valid pointers and add those
1294 * found to the gray list.
1295 */
1296static void scan_block(void *_start, void *_end,
Catalin Marinas93ada572015-06-24 16:58:37 -07001297 struct kmemleak_object *scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001298{
1299 unsigned long *ptr;
1300 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1301 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
Catalin Marinas93ada572015-06-24 16:58:37 -07001302 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001303
Catalin Marinas93ada572015-06-24 16:58:37 -07001304 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001305 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001306 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +01001307 unsigned long pointer;
Catalin Marinas94f4a162017-07-06 15:40:22 -07001308 unsigned long excess_ref;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001309
1310 if (scan_should_stop())
1311 break;
1312
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001313 kasan_disable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001314 pointer = *ptr;
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001315 kasan_enable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001316
Catalin Marinas93ada572015-06-24 16:58:37 -07001317 if (pointer < min_addr || pointer >= max_addr)
1318 continue;
1319
1320 /*
1321 * No need for get_object() here since we hold kmemleak_lock.
1322 * object->use_count cannot be dropped to 0 while the object
1323 * is still present in object_tree_root and object_list
1324 * (with updates protected by kmemleak_lock).
1325 */
1326 object = lookup_object(pointer, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001327 if (!object)
1328 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001329 if (object == scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001330 /* self referenced, ignore */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001331 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001332
1333 /*
1334 * Avoid the lockdep recursive warning on object->lock being
1335 * previously acquired in scan_object(). These locks are
1336 * enclosed by scan_mutex.
1337 */
Catalin Marinas93ada572015-06-24 16:58:37 -07001338 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001339 /* only pass surplus references (object already gray) */
1340 if (color_gray(object)) {
1341 excess_ref = object->excess_ref;
1342 /* no need for update_refs() if object already gray */
1343 } else {
1344 excess_ref = 0;
1345 update_refs(object);
1346 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001347 spin_unlock(&object->lock);
Catalin Marinas94f4a162017-07-06 15:40:22 -07001348
1349 if (excess_ref) {
1350 object = lookup_object(excess_ref, 0);
1351 if (!object)
1352 continue;
1353 if (object == scanned)
1354 /* circular reference, ignore */
1355 continue;
1356 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
1357 update_refs(object);
1358 spin_unlock(&object->lock);
1359 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001360 }
1361 read_unlock_irqrestore(&kmemleak_lock, flags);
1362}
Catalin Marinas0587da42009-10-28 13:33:11 +00001363
Catalin Marinas93ada572015-06-24 16:58:37 -07001364/*
1365 * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1366 */
1367static void scan_large_block(void *start, void *end)
1368{
1369 void *next;
1370
1371 while (start < end) {
1372 next = min(start + MAX_SCAN_SIZE, end);
1373 scan_block(start, next, NULL);
1374 start = next;
1375 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001376 }
1377}
1378
1379/*
1380 * Scan a memory block corresponding to a kmemleak_object. A condition is
1381 * that object->use_count >= 1.
1382 */
1383static void scan_object(struct kmemleak_object *object)
1384{
1385 struct kmemleak_scan_area *area;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001386 unsigned long flags;
1387
1388 /*
Uwe Kleine-König21ae2952009-10-07 15:21:09 +02001389 * Once the object->lock is acquired, the corresponding memory block
1390 * cannot be freed (the same lock is acquired in delete_object).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001391 */
1392 spin_lock_irqsave(&object->lock, flags);
1393 if (object->flags & OBJECT_NO_SCAN)
1394 goto out;
1395 if (!(object->flags & OBJECT_ALLOCATED))
1396 /* already freed object */
1397 goto out;
Catalin Marinasaf986032009-08-27 14:29:12 +01001398 if (hlist_empty(&object->area_list)) {
1399 void *start = (void *)object->pointer;
1400 void *end = (void *)(object->pointer + object->size);
Catalin Marinas93ada572015-06-24 16:58:37 -07001401 void *next;
Catalin Marinasaf986032009-08-27 14:29:12 +01001402
Catalin Marinas93ada572015-06-24 16:58:37 -07001403 do {
1404 next = min(start + MAX_SCAN_SIZE, end);
1405 scan_block(start, next, object);
1406
1407 start = next;
1408 if (start >= end)
1409 break;
Catalin Marinasaf986032009-08-27 14:29:12 +01001410
1411 spin_unlock_irqrestore(&object->lock, flags);
1412 cond_resched();
1413 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -07001414 } while (object->flags & OBJECT_ALLOCATED);
Catalin Marinasaf986032009-08-27 14:29:12 +01001415 } else
Sasha Levinb67bfe02013-02-27 17:06:00 -08001416 hlist_for_each_entry(area, &object->area_list, node)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001417 scan_block((void *)area->start,
1418 (void *)(area->start + area->size),
Catalin Marinas93ada572015-06-24 16:58:37 -07001419 object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001420out:
1421 spin_unlock_irqrestore(&object->lock, flags);
1422}
1423
1424/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001425 * Scan the objects already referenced (gray objects). More objects will be
1426 * referenced and, if there are no memory leaks, all the objects are scanned.
1427 */
1428static void scan_gray_list(void)
1429{
1430 struct kmemleak_object *object, *tmp;
1431
1432 /*
1433 * The list traversal is safe for both tail additions and removals
1434 * from inside the loop. The kmemleak objects cannot be freed from
1435 * outside the loop because their use_count was incremented.
1436 */
1437 object = list_entry(gray_list.next, typeof(*object), gray_list);
1438 while (&object->gray_list != &gray_list) {
1439 cond_resched();
1440
1441 /* may add new objects to the list */
1442 if (!scan_should_stop())
1443 scan_object(object);
1444
1445 tmp = list_entry(object->gray_list.next, typeof(*object),
1446 gray_list);
1447
1448 /* remove the object from the list and release it */
1449 list_del(&object->gray_list);
1450 put_object(object);
1451
1452 object = tmp;
1453 }
1454 WARN_ON(!list_empty(&gray_list));
1455}
1456
1457/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001458 * Scan data sections and all the referenced memory blocks allocated via the
1459 * kernel's standard allocators. This function must be called with the
1460 * scan_mutex held.
1461 */
1462static void kmemleak_scan(void)
1463{
1464 unsigned long flags;
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001465 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001466 int i;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001467 int new_leaks = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001468
Catalin Marinasacf49682009-06-26 17:38:29 +01001469 jiffies_last_scan = jiffies;
1470
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001471 /* prepare the kmemleak_object's */
1472 rcu_read_lock();
1473 list_for_each_entry_rcu(object, &object_list, object_list) {
1474 spin_lock_irqsave(&object->lock, flags);
1475#ifdef DEBUG
1476 /*
1477 * With a few exceptions there should be a maximum of
1478 * 1 reference to any object at this point.
1479 */
1480 if (atomic_read(&object->use_count) > 1) {
Joe Perchesae281062009-06-23 14:40:26 +01001481 pr_debug("object->use_count = %d\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001482 atomic_read(&object->use_count));
1483 dump_object_info(object);
1484 }
1485#endif
1486 /* reset the reference count (whiten the object) */
1487 object->count = 0;
1488 if (color_gray(object) && get_object(object))
1489 list_add_tail(&object->gray_list, &gray_list);
1490
1491 spin_unlock_irqrestore(&object->lock, flags);
1492 }
1493 rcu_read_unlock();
1494
1495 /* data/bss scanning */
Catalin Marinas93ada572015-06-24 16:58:37 -07001496 scan_large_block(_sdata, _edata);
1497 scan_large_block(__bss_start, __bss_stop);
Kees Cook906f2a52017-03-31 15:11:58 -07001498 scan_large_block(__start_ro_after_init, __end_ro_after_init);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001499
1500#ifdef CONFIG_SMP
1501 /* per-cpu sections scanning */
1502 for_each_possible_cpu(i)
Catalin Marinas93ada572015-06-24 16:58:37 -07001503 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1504 __per_cpu_end + per_cpu_offset(i));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001505#endif
1506
1507 /*
Laura Abbott029aeff2011-11-15 23:49:09 +00001508 * Struct page scanning for each node.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001509 */
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001510 get_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001511 for_each_online_node(i) {
Cody P Schafer108bcc92013-02-22 16:35:23 -08001512 unsigned long start_pfn = node_start_pfn(i);
1513 unsigned long end_pfn = node_end_pfn(i);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001514 unsigned long pfn;
1515
1516 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1517 struct page *page;
1518
1519 if (!pfn_valid(pfn))
1520 continue;
1521 page = pfn_to_page(pfn);
1522 /* only scan if page is in use */
1523 if (page_count(page) == 0)
1524 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001525 scan_block(page, page + 1, NULL);
Yisheng Xiebde5f6b2017-11-29 16:11:08 -08001526 if (!(pfn % (MAX_SCAN_SIZE / sizeof(*page))))
1527 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001528 }
1529 }
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001530 put_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001531
1532 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001533 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001534 */
1535 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001536 struct task_struct *p, *g;
1537
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001538 read_lock(&tasklist_lock);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001539 do_each_thread(g, p) {
Catalin Marinas37df49f2016-10-27 17:46:47 -07001540 void *stack = try_get_task_stack(p);
1541 if (stack) {
1542 scan_block(stack, stack + THREAD_SIZE, NULL);
1543 put_task_stack(p);
1544 }
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001545 } while_each_thread(g, p);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001546 read_unlock(&tasklist_lock);
1547 }
1548
1549 /*
1550 * Scan the objects already referenced from the sections scanned
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001551 * above.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001552 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001553 scan_gray_list();
Catalin Marinas25873622009-07-07 10:32:58 +01001554
1555 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001556 * Check for new or unreferenced objects modified since the previous
1557 * scan and color them gray until the next scan.
Catalin Marinas25873622009-07-07 10:32:58 +01001558 */
1559 rcu_read_lock();
1560 list_for_each_entry_rcu(object, &object_list, object_list) {
1561 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001562 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1563 && update_checksum(object) && get_object(object)) {
1564 /* color it gray temporarily */
1565 object->count = object->min_count;
Catalin Marinas25873622009-07-07 10:32:58 +01001566 list_add_tail(&object->gray_list, &gray_list);
1567 }
1568 spin_unlock_irqrestore(&object->lock, flags);
1569 }
1570 rcu_read_unlock();
1571
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001572 /*
1573 * Re-scan the gray list for modified unreferenced objects.
1574 */
1575 scan_gray_list();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001576
1577 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001578 * If scanning was stopped do not report any new unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001579 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001580 if (scan_should_stop())
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001581 return;
1582
1583 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001584 * Scanning result reporting.
1585 */
1586 rcu_read_lock();
1587 list_for_each_entry_rcu(object, &object_list, object_list) {
1588 spin_lock_irqsave(&object->lock, flags);
1589 if (unreferenced_object(object) &&
1590 !(object->flags & OBJECT_REPORTED)) {
1591 object->flags |= OBJECT_REPORTED;
1592 new_leaks++;
1593 }
1594 spin_unlock_irqrestore(&object->lock, flags);
1595 }
1596 rcu_read_unlock();
1597
Li Zefandc9b3f42014-04-03 14:46:26 -07001598 if (new_leaks) {
1599 kmemleak_found_leaks = true;
1600
Joe Perches756a0252016-03-17 14:19:47 -07001601 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1602 new_leaks);
Li Zefandc9b3f42014-04-03 14:46:26 -07001603 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001604
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001605}
1606
1607/*
1608 * Thread function performing automatic memory scanning. Unreferenced objects
1609 * at the end of a memory scan are reported but only the first time.
1610 */
1611static int kmemleak_scan_thread(void *arg)
1612{
1613 static int first_run = 1;
1614
Joe Perchesae281062009-06-23 14:40:26 +01001615 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001616 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001617
1618 /*
1619 * Wait before the first scan to allow the system to fully initialize.
1620 */
1621 if (first_run) {
Vegard Nossum98c42d92016-07-28 15:48:32 -07001622 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001623 first_run = 0;
Vegard Nossum98c42d92016-07-28 15:48:32 -07001624 while (timeout && !kthread_should_stop())
1625 timeout = schedule_timeout_interruptible(timeout);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001626 }
1627
1628 while (!kthread_should_stop()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001629 signed long timeout = jiffies_scan_wait;
1630
1631 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001632 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001633 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001634
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001635 /* wait before the next scan */
1636 while (timeout && !kthread_should_stop())
1637 timeout = schedule_timeout_interruptible(timeout);
1638 }
1639
Joe Perchesae281062009-06-23 14:40:26 +01001640 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001641
1642 return 0;
1643}
1644
1645/*
1646 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001647 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001648 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001649static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001650{
1651 if (scan_thread)
1652 return;
1653 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1654 if (IS_ERR(scan_thread)) {
Joe Perches598d8092016-03-17 14:19:44 -07001655 pr_warn("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001656 scan_thread = NULL;
1657 }
1658}
1659
1660/*
1661 * Stop the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001662 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001663 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001664static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001665{
1666 if (scan_thread) {
1667 kthread_stop(scan_thread);
1668 scan_thread = NULL;
1669 }
1670}
1671
1672/*
1673 * Iterate over the object_list and return the first valid object at or after
1674 * the required position with its use_count incremented. The function triggers
1675 * a memory scanning when the pos argument points to the first position.
1676 */
1677static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1678{
1679 struct kmemleak_object *object;
1680 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001681 int err;
1682
1683 err = mutex_lock_interruptible(&scan_mutex);
1684 if (err < 0)
1685 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001686
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001687 rcu_read_lock();
1688 list_for_each_entry_rcu(object, &object_list, object_list) {
1689 if (n-- > 0)
1690 continue;
1691 if (get_object(object))
1692 goto out;
1693 }
1694 object = NULL;
1695out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001696 return object;
1697}
1698
1699/*
1700 * Return the next object in the object_list. The function decrements the
1701 * use_count of the previous object and increases that of the next one.
1702 */
1703static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1704{
1705 struct kmemleak_object *prev_obj = v;
1706 struct kmemleak_object *next_obj = NULL;
Michael Wang58fac092012-08-17 12:33:34 +08001707 struct kmemleak_object *obj = prev_obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001708
1709 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001710
Michael Wang58fac092012-08-17 12:33:34 +08001711 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001712 if (get_object(obj)) {
1713 next_obj = obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001714 break;
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001715 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001716 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001717
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001718 put_object(prev_obj);
1719 return next_obj;
1720}
1721
1722/*
1723 * Decrement the use_count of the last object required, if any.
1724 */
1725static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1726{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001727 if (!IS_ERR(v)) {
1728 /*
1729 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1730 * waiting was interrupted, so only release it if !IS_ERR.
1731 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001732 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001733 mutex_unlock(&scan_mutex);
1734 if (v)
1735 put_object(v);
1736 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001737}
1738
1739/*
1740 * Print the information for an unreferenced object to the seq file.
1741 */
1742static int kmemleak_seq_show(struct seq_file *seq, void *v)
1743{
1744 struct kmemleak_object *object = v;
1745 unsigned long flags;
1746
1747 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001748 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001749 print_unreferenced(seq, object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001750 spin_unlock_irqrestore(&object->lock, flags);
1751 return 0;
1752}
1753
1754static const struct seq_operations kmemleak_seq_ops = {
1755 .start = kmemleak_seq_start,
1756 .next = kmemleak_seq_next,
1757 .stop = kmemleak_seq_stop,
1758 .show = kmemleak_seq_show,
1759};
1760
1761static int kmemleak_open(struct inode *inode, struct file *file)
1762{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001763 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001764}
1765
Catalin Marinas189d84e2009-08-27 14:29:15 +01001766static int dump_str_object_info(const char *str)
1767{
1768 unsigned long flags;
1769 struct kmemleak_object *object;
1770 unsigned long addr;
1771
Abhijit Pawardc053732012-12-18 14:23:27 -08001772 if (kstrtoul(str, 0, &addr))
1773 return -EINVAL;
Catalin Marinas189d84e2009-08-27 14:29:15 +01001774 object = find_and_get_object(addr, 0);
1775 if (!object) {
1776 pr_info("Unknown object at 0x%08lx\n", addr);
1777 return -EINVAL;
1778 }
1779
1780 spin_lock_irqsave(&object->lock, flags);
1781 dump_object_info(object);
1782 spin_unlock_irqrestore(&object->lock, flags);
1783
1784 put_object(object);
1785 return 0;
1786}
1787
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001788/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001789 * We use grey instead of black to ensure we can do future scans on the same
1790 * objects. If we did not do future scans these black objects could
1791 * potentially contain references to newly allocated objects in the future and
1792 * we'd end up with false positives.
1793 */
1794static void kmemleak_clear(void)
1795{
1796 struct kmemleak_object *object;
1797 unsigned long flags;
1798
1799 rcu_read_lock();
1800 list_for_each_entry_rcu(object, &object_list, object_list) {
1801 spin_lock_irqsave(&object->lock, flags);
1802 if ((object->flags & OBJECT_REPORTED) &&
1803 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001804 __paint_it(object, KMEMLEAK_GREY);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001805 spin_unlock_irqrestore(&object->lock, flags);
1806 }
1807 rcu_read_unlock();
Li Zefandc9b3f42014-04-03 14:46:26 -07001808
1809 kmemleak_found_leaks = false;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001810}
1811
Li Zefanc89da702014-04-03 14:46:27 -07001812static void __kmemleak_do_cleanup(void);
1813
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001814/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001815 * File write operation to configure kmemleak at run-time. The following
1816 * commands can be written to the /sys/kernel/debug/kmemleak file:
1817 * off - disable kmemleak (irreversible)
1818 * stack=on - enable the task stacks scanning
1819 * stack=off - disable the tasks stacks scanning
1820 * scan=on - start the automatic memory scanning thread
1821 * scan=off - stop the automatic memory scanning thread
1822 * scan=... - set the automatic memory scanning period in seconds (0 to
1823 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001824 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001825 * clear - mark all current reported unreferenced kmemleak objects as
Li Zefanc89da702014-04-03 14:46:27 -07001826 * grey to ignore printing them, or free all kmemleak objects
1827 * if kmemleak has been disabled.
Catalin Marinas189d84e2009-08-27 14:29:15 +01001828 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001829 */
1830static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1831 size_t size, loff_t *ppos)
1832{
1833 char buf[64];
1834 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001835 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001836
1837 buf_size = min(size, (sizeof(buf) - 1));
1838 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1839 return -EFAULT;
1840 buf[buf_size] = 0;
1841
Catalin Marinasb87324d2009-07-07 10:32:58 +01001842 ret = mutex_lock_interruptible(&scan_mutex);
1843 if (ret < 0)
1844 return ret;
1845
Li Zefanc89da702014-04-03 14:46:27 -07001846 if (strncmp(buf, "clear", 5) == 0) {
Li Zefan8910ae82014-04-03 14:46:29 -07001847 if (kmemleak_enabled)
Li Zefanc89da702014-04-03 14:46:27 -07001848 kmemleak_clear();
1849 else
1850 __kmemleak_do_cleanup();
1851 goto out;
1852 }
1853
Li Zefan8910ae82014-04-03 14:46:29 -07001854 if (!kmemleak_enabled) {
Li Zefanc89da702014-04-03 14:46:27 -07001855 ret = -EBUSY;
1856 goto out;
1857 }
1858
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001859 if (strncmp(buf, "off", 3) == 0)
1860 kmemleak_disable();
1861 else if (strncmp(buf, "stack=on", 8) == 0)
1862 kmemleak_stack_scan = 1;
1863 else if (strncmp(buf, "stack=off", 9) == 0)
1864 kmemleak_stack_scan = 0;
1865 else if (strncmp(buf, "scan=on", 7) == 0)
1866 start_scan_thread();
1867 else if (strncmp(buf, "scan=off", 8) == 0)
1868 stop_scan_thread();
1869 else if (strncmp(buf, "scan=", 5) == 0) {
1870 unsigned long secs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001871
Jingoo Han3dbb95f2013-09-11 14:20:25 -07001872 ret = kstrtoul(buf + 5, 0, &secs);
Catalin Marinasb87324d2009-07-07 10:32:58 +01001873 if (ret < 0)
1874 goto out;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001875 stop_scan_thread();
1876 if (secs) {
1877 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1878 start_scan_thread();
1879 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001880 } else if (strncmp(buf, "scan", 4) == 0)
1881 kmemleak_scan();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001882 else if (strncmp(buf, "dump=", 5) == 0)
1883 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001884 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001885 ret = -EINVAL;
1886
1887out:
1888 mutex_unlock(&scan_mutex);
1889 if (ret < 0)
1890 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001891
1892 /* ignore the rest of the buffer, only one command at a time */
1893 *ppos += size;
1894 return size;
1895}
1896
1897static const struct file_operations kmemleak_fops = {
1898 .owner = THIS_MODULE,
1899 .open = kmemleak_open,
1900 .read = seq_read,
1901 .write = kmemleak_write,
1902 .llseek = seq_lseek,
Li Zefan5f3bf192014-04-03 14:46:28 -07001903 .release = seq_release,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001904};
1905
Li Zefanc89da702014-04-03 14:46:27 -07001906static void __kmemleak_do_cleanup(void)
1907{
1908 struct kmemleak_object *object;
1909
1910 rcu_read_lock();
1911 list_for_each_entry_rcu(object, &object_list, object_list)
1912 delete_object_full(object->pointer);
1913 rcu_read_unlock();
1914}
1915
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001916/*
Catalin Marinas74341702011-09-29 11:50:07 +01001917 * Stop the memory scanning thread and free the kmemleak internal objects if
1918 * no previous scan thread (otherwise, kmemleak may still have some useful
1919 * information on memory leaks).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001920 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001921static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001922{
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001923 stop_scan_thread();
1924
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001925 /*
1926 * Once the scan thread has stopped, it is safe to no longer track
1927 * object freeing. Ordering of the scan thread stopping and the memory
1928 * accesses below is guaranteed by the kthread_stop() function.
1929 */
1930 kmemleak_free_enabled = 0;
1931
Li Zefanc89da702014-04-03 14:46:27 -07001932 if (!kmemleak_found_leaks)
1933 __kmemleak_do_cleanup();
1934 else
Joe Perches756a0252016-03-17 14:19:47 -07001935 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 +01001936}
1937
Catalin Marinas179a8102009-09-07 10:14:42 +01001938static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001939
1940/*
1941 * Disable kmemleak. No memory allocation/freeing will be traced once this
1942 * function is called. Disabling kmemleak is an irreversible operation.
1943 */
1944static void kmemleak_disable(void)
1945{
1946 /* atomically check whether it was already invoked */
Li Zefan8910ae82014-04-03 14:46:29 -07001947 if (cmpxchg(&kmemleak_error, 0, 1))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001948 return;
1949
1950 /* stop any memory operation tracing */
Li Zefan8910ae82014-04-03 14:46:29 -07001951 kmemleak_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001952
1953 /* check whether it is too early for a kernel thread */
Li Zefan8910ae82014-04-03 14:46:29 -07001954 if (kmemleak_initialized)
Catalin Marinas179a8102009-09-07 10:14:42 +01001955 schedule_work(&cleanup_work);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001956 else
1957 kmemleak_free_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001958
1959 pr_info("Kernel memory leak detector disabled\n");
1960}
1961
1962/*
1963 * Allow boot-time kmemleak disabling (enabled by default).
1964 */
1965static int kmemleak_boot_config(char *str)
1966{
1967 if (!str)
1968 return -EINVAL;
1969 if (strcmp(str, "off") == 0)
1970 kmemleak_disable();
Jason Baronab0155a2010-07-19 11:54:17 +01001971 else if (strcmp(str, "on") == 0)
1972 kmemleak_skip_disable = 1;
1973 else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001974 return -EINVAL;
1975 return 0;
1976}
1977early_param("kmemleak", kmemleak_boot_config);
1978
Catalin Marinas5f790202011-09-28 12:17:03 +01001979static void __init print_log_trace(struct early_log *log)
1980{
1981 struct stack_trace trace;
1982
1983 trace.nr_entries = log->trace_len;
1984 trace.entries = log->trace;
1985
1986 pr_notice("Early log backtrace:\n");
1987 print_stack_trace(&trace, 2);
1988}
1989
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001990/*
Catalin Marinas20301172009-06-17 18:29:04 +01001991 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001992 */
1993void __init kmemleak_init(void)
1994{
1995 int i;
1996 unsigned long flags;
1997
Jason Baronab0155a2010-07-19 11:54:17 +01001998#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
1999 if (!kmemleak_skip_disable) {
Catalin Marinas3551a922014-05-09 15:36:59 -07002000 kmemleak_early_log = 0;
Jason Baronab0155a2010-07-19 11:54:17 +01002001 kmemleak_disable();
2002 return;
2003 }
2004#endif
2005
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002006 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
2007 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
2008
2009 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
2010 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002011
Wang Kai21cd3a62015-09-08 15:03:41 -07002012 if (crt_early_log > ARRAY_SIZE(early_log))
Joe Perches598d8092016-03-17 14:19:44 -07002013 pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
2014 crt_early_log);
Catalin Marinasb6693002011-09-28 17:22:56 +01002015
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002016 /* the kernel is still in UP mode, so disabling the IRQs is enough */
2017 local_irq_save(flags);
Catalin Marinas3551a922014-05-09 15:36:59 -07002018 kmemleak_early_log = 0;
Li Zefan8910ae82014-04-03 14:46:29 -07002019 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +01002020 local_irq_restore(flags);
2021 return;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002022 } else {
Li Zefan8910ae82014-04-03 14:46:29 -07002023 kmemleak_enabled = 1;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07002024 kmemleak_free_enabled = 1;
2025 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002026 local_irq_restore(flags);
2027
2028 /*
2029 * This is the point where tracking allocations is safe. Automatic
2030 * scanning is started during the late initcall. Add the early logged
2031 * callbacks to the kmemleak infrastructure.
2032 */
2033 for (i = 0; i < crt_early_log; i++) {
2034 struct early_log *log = &early_log[i];
2035
2036 switch (log->op_type) {
2037 case KMEMLEAK_ALLOC:
Catalin Marinasfd678962009-08-27 14:29:17 +01002038 early_alloc(log);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002039 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002040 case KMEMLEAK_ALLOC_PERCPU:
2041 early_alloc_percpu(log);
2042 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002043 case KMEMLEAK_FREE:
2044 kmemleak_free(log->ptr);
2045 break;
Catalin Marinas53238a62009-07-07 10:33:00 +01002046 case KMEMLEAK_FREE_PART:
2047 kmemleak_free_part(log->ptr, log->size);
2048 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01002049 case KMEMLEAK_FREE_PERCPU:
2050 kmemleak_free_percpu(log->ptr);
2051 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002052 case KMEMLEAK_NOT_LEAK:
2053 kmemleak_not_leak(log->ptr);
2054 break;
2055 case KMEMLEAK_IGNORE:
2056 kmemleak_ignore(log->ptr);
2057 break;
2058 case KMEMLEAK_SCAN_AREA:
Catalin Marinasc017b4b2009-10-28 13:33:09 +00002059 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002060 break;
2061 case KMEMLEAK_NO_SCAN:
2062 kmemleak_no_scan(log->ptr);
2063 break;
Catalin Marinas94f4a162017-07-06 15:40:22 -07002064 case KMEMLEAK_SET_EXCESS_REF:
2065 object_set_excess_ref((unsigned long)log->ptr,
2066 log->excess_ref);
2067 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002068 default:
Catalin Marinas5f790202011-09-28 12:17:03 +01002069 kmemleak_warn("Unknown early log operation: %d\n",
2070 log->op_type);
2071 }
2072
Li Zefan8910ae82014-04-03 14:46:29 -07002073 if (kmemleak_warning) {
Catalin Marinas5f790202011-09-28 12:17:03 +01002074 print_log_trace(log);
Li Zefan8910ae82014-04-03 14:46:29 -07002075 kmemleak_warning = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002076 }
2077 }
2078}
2079
2080/*
2081 * Late initialization function.
2082 */
2083static int __init kmemleak_late_init(void)
2084{
2085 struct dentry *dentry;
2086
Li Zefan8910ae82014-04-03 14:46:29 -07002087 kmemleak_initialized = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002088
Li Zefan8910ae82014-04-03 14:46:29 -07002089 if (kmemleak_error) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002090 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002091 * Some error occurred and kmemleak was disabled. There is a
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002092 * small chance that kmemleak_disable() was called immediately
2093 * after setting kmemleak_initialized and we may end up with
2094 * two clean-up threads but serialized by scan_mutex.
2095 */
Catalin Marinas179a8102009-09-07 10:14:42 +01002096 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002097 return -ENOMEM;
2098 }
2099
Konstantin Khlebnikov7d6c4df2017-11-15 17:35:30 -08002100 dentry = debugfs_create_file("kmemleak", 0644, NULL, NULL,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002101 &kmemleak_fops);
2102 if (!dentry)
Joe Perches598d8092016-03-17 14:19:44 -07002103 pr_warn("Failed to create the debugfs kmemleak file\n");
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002104 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002105 start_scan_thread();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002106 mutex_unlock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002107
2108 pr_info("Kernel memory leak detector initialized\n");
2109
2110 return 0;
2111}
2112late_initcall(kmemleak_late_init);