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Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001/*
2 * mm/kmemleak.c
3 *
4 * Copyright (C) 2008 ARM Limited
5 * Written by Catalin Marinas <catalin.marinas@arm.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 *
21 * For more information on the algorithm and kmemleak usage, please see
22 * Documentation/kmemleak.txt.
23 *
24 * Notes on locking
25 * ----------------
26 *
27 * The following locks and mutexes are used by kmemleak:
28 *
29 * - kmemleak_lock (rwlock): protects the object_list modifications and
30 * accesses to the object_tree_root. The object_list is the main list
31 * holding the metadata (struct kmemleak_object) for the allocated memory
Michel Lespinasse85d3a312012-10-08 16:31:27 -070032 * blocks. The object_tree_root is a red black tree used to look-up
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010033 * metadata based on a pointer to the corresponding memory block. The
34 * kmemleak_object structures are added to the object_list and
35 * object_tree_root in the create_object() function called from the
36 * kmemleak_alloc() callback and removed in delete_object() called from the
37 * kmemleak_free() callback
38 * - kmemleak_object.lock (spinlock): protects a kmemleak_object. Accesses to
39 * the metadata (e.g. count) are protected by this lock. Note that some
40 * members of this structure may be protected by other means (atomic or
41 * kmemleak_lock). This lock is also held when scanning the corresponding
42 * memory block to avoid the kernel freeing it via the kmemleak_free()
43 * callback. This is less heavyweight than holding a global lock like
44 * kmemleak_lock during scanning
45 * - scan_mutex (mutex): ensures that only one thread may scan the memory for
46 * unreferenced objects at a time. The gray_list contains the objects which
47 * are already referenced or marked as false positives and need to be
48 * scanned. This list is only modified during a scanning episode when the
49 * scan_mutex is held. At the end of a scan, the gray_list is always empty.
50 * Note that the kmemleak_object.use_count is incremented when an object is
Catalin Marinas4698c1f2009-06-26 17:38:27 +010051 * added to the gray_list and therefore cannot be freed. This mutex also
52 * prevents multiple users of the "kmemleak" debugfs file together with
53 * modifications to the memory scanning parameters including the scan_thread
54 * pointer
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010055 *
Catalin Marinas93ada572015-06-24 16:58:37 -070056 * Locks and mutexes are acquired/nested in the following order:
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070057 *
Catalin Marinas93ada572015-06-24 16:58:37 -070058 * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING)
59 *
60 * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex
61 * regions.
Catalin Marinas9d5a4c72015-06-24 16:58:34 -070062 *
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010063 * The kmemleak_object structures have a use_count incremented or decremented
64 * using the get_object()/put_object() functions. When the use_count becomes
65 * 0, this count can no longer be incremented and put_object() schedules the
66 * kmemleak_object freeing via an RCU callback. All calls to the get_object()
67 * function must be protected by rcu_read_lock() to avoid accessing a freed
68 * structure.
69 */
70
Joe Perchesae281062009-06-23 14:40:26 +010071#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
72
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010073#include <linux/init.h>
74#include <linux/kernel.h>
75#include <linux/list.h>
76#include <linux/sched.h>
77#include <linux/jiffies.h>
78#include <linux/delay.h>
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040079#include <linux/export.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010080#include <linux/kthread.h>
Michel Lespinasse85d3a312012-10-08 16:31:27 -070081#include <linux/rbtree.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010082#include <linux/fs.h>
83#include <linux/debugfs.h>
84#include <linux/seq_file.h>
85#include <linux/cpumask.h>
86#include <linux/spinlock.h>
87#include <linux/mutex.h>
88#include <linux/rcupdate.h>
89#include <linux/stacktrace.h>
90#include <linux/cache.h>
91#include <linux/percpu.h>
92#include <linux/hardirq.h>
Catalin Marinas9099dae2016-10-11 13:55:11 -070093#include <linux/bootmem.h>
94#include <linux/pfn.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +010095#include <linux/mmzone.h>
96#include <linux/slab.h>
97#include <linux/thread_info.h>
98#include <linux/err.h>
99#include <linux/uaccess.h>
100#include <linux/string.h>
101#include <linux/nodemask.h>
102#include <linux/mm.h>
Catalin Marinas179a8102009-09-07 10:14:42 +0100103#include <linux/workqueue.h>
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000104#include <linux/crc32.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100105
106#include <asm/sections.h>
107#include <asm/processor.h>
Arun Sharma600634972011-07-26 16:09:06 -0700108#include <linux/atomic.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100109
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -0800110#include <linux/kasan.h>
Pekka Enberg8e019362009-08-27 14:50:00 +0100111#include <linux/kmemcheck.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100112#include <linux/kmemleak.h>
Laura Abbott029aeff2011-11-15 23:49:09 +0000113#include <linux/memory_hotplug.h>
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100114
115/*
116 * Kmemleak configuration and common defines.
117 */
118#define MAX_TRACE 16 /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100119#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100120#define SECS_FIRST_SCAN 60 /* delay before the first scan */
121#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
Catalin Marinasaf986032009-08-27 14:29:12 +0100122#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100123
124#define BYTES_PER_POINTER sizeof(void *)
125
Catalin Marinas216c04b2009-06-17 18:29:02 +0100126/* GFP bitmask for kmemleak internal allocations */
Vladimir Davydov20b5c302016-01-14 15:18:08 -0800127#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000128 __GFP_NORETRY | __GFP_NOMEMALLOC | \
129 __GFP_NOWARN)
Catalin Marinas216c04b2009-06-17 18:29:02 +0100130
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100131/* scanning area inside a memory block */
132struct kmemleak_scan_area {
133 struct hlist_node node;
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000134 unsigned long start;
135 size_t size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100136};
137
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700138#define KMEMLEAK_GREY 0
139#define KMEMLEAK_BLACK -1
140
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100141/*
142 * Structure holding the metadata for each allocated memory block.
143 * Modifications to such objects should be made while holding the
144 * object->lock. Insertions or deletions from object_list, gray_list or
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700145 * rb_node are already protected by the corresponding locks or mutex (see
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100146 * the notes on locking above). These objects are reference-counted
147 * (use_count) and freed using the RCU mechanism.
148 */
149struct kmemleak_object {
150 spinlock_t lock;
151 unsigned long flags; /* object status flags */
152 struct list_head object_list;
153 struct list_head gray_list;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700154 struct rb_node rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100155 struct rcu_head rcu; /* object_list lockless traversal */
156 /* object usage count; object freed when use_count == 0 */
157 atomic_t use_count;
158 unsigned long pointer;
159 size_t size;
160 /* minimum number of a pointers found before it is considered leak */
161 int min_count;
162 /* the total number of pointers found pointing to this object */
163 int count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000164 /* checksum for detecting modified objects */
165 u32 checksum;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100166 /* memory ranges to be scanned inside an object (empty for all) */
167 struct hlist_head area_list;
168 unsigned long trace[MAX_TRACE];
169 unsigned int trace_len;
170 unsigned long jiffies; /* creation timestamp */
171 pid_t pid; /* pid of the current task */
172 char comm[TASK_COMM_LEN]; /* executable name */
173};
174
175/* flag representing the memory block allocation status */
176#define OBJECT_ALLOCATED (1 << 0)
177/* flag set after the first reporting of an unreference object */
178#define OBJECT_REPORTED (1 << 1)
179/* flag set to not scan the object */
180#define OBJECT_NO_SCAN (1 << 2)
181
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100182/* number of bytes to print per line; must be 16 or 32 */
183#define HEX_ROW_SIZE 16
184/* number of bytes to print at a time (1, 2, 4, 8) */
185#define HEX_GROUP_SIZE 1
186/* include ASCII after the hex output */
187#define HEX_ASCII 1
188/* max number of lines to be printed */
189#define HEX_MAX_LINES 2
190
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100191/* the list of all allocated objects */
192static LIST_HEAD(object_list);
193/* the list of gray-colored objects (see color_gray comment below) */
194static LIST_HEAD(gray_list);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700195/* search tree for object boundaries */
196static struct rb_root object_tree_root = RB_ROOT;
197/* rw_lock protecting the access to object_list and object_tree_root */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100198static DEFINE_RWLOCK(kmemleak_lock);
199
200/* allocation caches for kmemleak internal data */
201static struct kmem_cache *object_cache;
202static struct kmem_cache *scan_area_cache;
203
204/* set if tracing memory operations is enabled */
Li Zefan8910ae82014-04-03 14:46:29 -0700205static int kmemleak_enabled;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700206/* same as above but only for the kmemleak_free() callback */
207static int kmemleak_free_enabled;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100208/* set in the late_initcall if there were no errors */
Li Zefan8910ae82014-04-03 14:46:29 -0700209static int kmemleak_initialized;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100210/* enables or disables early logging of the memory operations */
Li Zefan8910ae82014-04-03 14:46:29 -0700211static int kmemleak_early_log = 1;
Catalin Marinas5f790202011-09-28 12:17:03 +0100212/* set if a kmemleak warning was issued */
Li Zefan8910ae82014-04-03 14:46:29 -0700213static int kmemleak_warning;
Catalin Marinas5f790202011-09-28 12:17:03 +0100214/* set if a fatal kmemleak error has occurred */
Li Zefan8910ae82014-04-03 14:46:29 -0700215static int kmemleak_error;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100216
217/* minimum and maximum address that may be valid pointers */
218static unsigned long min_addr = ULONG_MAX;
219static unsigned long max_addr;
220
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100221static struct task_struct *scan_thread;
Catalin Marinasacf49682009-06-26 17:38:29 +0100222/* used to avoid reporting of recently allocated objects */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100223static unsigned long jiffies_min_age;
Catalin Marinasacf49682009-06-26 17:38:29 +0100224static unsigned long jiffies_last_scan;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100225/* delay between automatic memory scannings */
226static signed long jiffies_scan_wait;
Vignesh Radhakrishnand1fdabf2015-01-22 11:43:45 +0530227
228/*
229 * Enables or disables the task stacks scanning.
230 * Set to 1 if at compile time we want it enabled.
231 * Else set to 0 to have it disabled by default.
232 * This can be enabled by writing to "stack=on" using
233 * kmemleak debugfs entry.
234 */
235#ifdef CONFIG_DEBUG_TASK_STACK_SCAN_OFF
236static int kmemleak_stack_scan;
237#else
Catalin Marinase0a2a162009-06-26 17:38:25 +0100238static int kmemleak_stack_scan = 1;
Vignesh Radhakrishnand1fdabf2015-01-22 11:43:45 +0530239#endif
240
Catalin Marinas4698c1f2009-06-26 17:38:27 +0100241/* protects the memory scanning, parameters and debug/kmemleak file access */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100242static DEFINE_MUTEX(scan_mutex);
Jason Baronab0155a2010-07-19 11:54:17 +0100243/* setting kmemleak=on, will set this var, skipping the disable */
244static int kmemleak_skip_disable;
Li Zefandc9b3f42014-04-03 14:46:26 -0700245/* If there are leaks that can be reported */
246static bool kmemleak_found_leaks;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100247
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100248/*
Catalin Marinas20301172009-06-17 18:29:04 +0100249 * Early object allocation/freeing logging. Kmemleak is initialized after the
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100250 * kernel allocator. However, both the kernel allocator and kmemleak may
Catalin Marinas20301172009-06-17 18:29:04 +0100251 * allocate memory blocks which need to be tracked. Kmemleak defines an
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100252 * arbitrary buffer to hold the allocation/freeing information before it is
253 * fully initialized.
254 */
255
256/* kmemleak operation type for early logging */
257enum {
258 KMEMLEAK_ALLOC,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100259 KMEMLEAK_ALLOC_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100260 KMEMLEAK_FREE,
Catalin Marinas53238a62009-07-07 10:33:00 +0100261 KMEMLEAK_FREE_PART,
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100262 KMEMLEAK_FREE_PERCPU,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100263 KMEMLEAK_NOT_LEAK,
264 KMEMLEAK_IGNORE,
265 KMEMLEAK_SCAN_AREA,
266 KMEMLEAK_NO_SCAN
267};
268
269/*
270 * Structure holding the information passed to kmemleak callbacks during the
271 * early logging.
272 */
273struct early_log {
274 int op_type; /* kmemleak operation type */
275 const void *ptr; /* allocated/freed memory block */
276 size_t size; /* memory block size */
277 int min_count; /* minimum reference count */
Catalin Marinasfd678962009-08-27 14:29:17 +0100278 unsigned long trace[MAX_TRACE]; /* stack trace */
279 unsigned int trace_len; /* stack trace length */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100280};
281
282/* early logging buffer and current position */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100283static struct early_log
284 early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
285static int crt_early_log __initdata;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100286
287static void kmemleak_disable(void);
288
289/*
290 * Print a warning and dump the stack trace.
291 */
Catalin Marinas5f790202011-09-28 12:17:03 +0100292#define kmemleak_warn(x...) do { \
Joe Perches598d8092016-03-17 14:19:44 -0700293 pr_warn(x); \
Catalin Marinas5f790202011-09-28 12:17:03 +0100294 dump_stack(); \
Li Zefan8910ae82014-04-03 14:46:29 -0700295 kmemleak_warning = 1; \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100296} while (0)
297
298/*
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300299 * Macro invoked when a serious kmemleak condition occurred and cannot be
Catalin Marinas20301172009-06-17 18:29:04 +0100300 * recovered from. Kmemleak will be disabled and further allocation/freeing
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100301 * tracing no longer available.
302 */
Catalin Marinas000814f2009-06-17 18:29:03 +0100303#define kmemleak_stop(x...) do { \
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100304 kmemleak_warn(x); \
305 kmemleak_disable(); \
306} while (0)
307
308/*
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100309 * Printing of the objects hex dump to the seq file. The number of lines to be
310 * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
311 * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
312 * with the object->lock held.
313 */
314static void hex_dump_object(struct seq_file *seq,
315 struct kmemleak_object *object)
316{
317 const u8 *ptr = (const u8 *)object->pointer;
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700318 size_t len;
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100319
320 /* limit the number of lines to HEX_MAX_LINES */
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700321 len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100322
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700323 seq_printf(seq, " hex dump (first %zu bytes):\n", len);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700324 kasan_disable_current();
Andy Shevchenko6fc37c42015-09-09 15:38:45 -0700325 seq_hex_dump(seq, " ", DUMP_PREFIX_NONE, HEX_ROW_SIZE,
326 HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
Dmitry Vyukov5c335fe2016-06-24 14:50:07 -0700327 kasan_enable_current();
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100328}
329
330/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100331 * Object colors, encoded with count and min_count:
332 * - white - orphan object, not enough references to it (count < min_count)
333 * - gray - not orphan, not marked as false positive (min_count == 0) or
334 * sufficient references to it (count >= min_count)
335 * - black - ignore, it doesn't contain references (e.g. text section)
336 * (min_count == -1). No function defined for this color.
337 * Newly created objects don't have any color assigned (object->count == -1)
338 * before the next memory scan when they become white.
339 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100340static bool color_white(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100341{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700342 return object->count != KMEMLEAK_BLACK &&
343 object->count < object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100344}
345
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100346static bool color_gray(const struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100347{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700348 return object->min_count != KMEMLEAK_BLACK &&
349 object->count >= object->min_count;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100350}
351
352/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100353 * Objects are considered unreferenced only if their color is white, they have
354 * not be deleted and have a minimum age to avoid false positives caused by
355 * pointers temporarily stored in CPU registers.
356 */
Luis R. Rodriguez4a558dd2009-09-08 16:34:50 +0100357static bool unreferenced_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100358{
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000359 return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
Catalin Marinasacf49682009-06-26 17:38:29 +0100360 time_before_eq(object->jiffies + jiffies_min_age,
361 jiffies_last_scan);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100362}
363
364/*
Catalin Marinasbab4a342009-06-26 17:38:26 +0100365 * Printing of the unreferenced objects information to the seq file. The
366 * print_unreferenced function must be called with the object->lock held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100367 */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100368static void print_unreferenced(struct seq_file *seq,
369 struct kmemleak_object *object)
370{
371 int i;
Catalin Marinasfefdd332009-10-28 13:33:12 +0000372 unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100373
Catalin Marinasbab4a342009-06-26 17:38:26 +0100374 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
375 object->pointer, object->size);
Catalin Marinasfefdd332009-10-28 13:33:12 +0000376 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
377 object->comm, object->pid, object->jiffies,
378 msecs_age / 1000, msecs_age % 1000);
Sergey Senozhatsky0494e082009-08-27 14:29:18 +0100379 hex_dump_object(seq, object);
Catalin Marinasbab4a342009-06-26 17:38:26 +0100380 seq_printf(seq, " backtrace:\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100381
382 for (i = 0; i < object->trace_len; i++) {
383 void *ptr = (void *)object->trace[i];
Catalin Marinasbab4a342009-06-26 17:38:26 +0100384 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100385 }
386}
387
388/*
389 * Print the kmemleak_object information. This function is used mainly for
390 * debugging special cases when kmemleak operations. It must be called with
391 * the object->lock held.
392 */
393static void dump_object_info(struct kmemleak_object *object)
394{
395 struct stack_trace trace;
396
397 trace.nr_entries = object->trace_len;
398 trace.entries = object->trace;
399
Joe Perchesae281062009-06-23 14:40:26 +0100400 pr_notice("Object 0x%08lx (size %zu):\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700401 object->pointer, object->size);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100402 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n",
403 object->comm, object->pid, object->jiffies);
404 pr_notice(" min_count = %d\n", object->min_count);
405 pr_notice(" count = %d\n", object->count);
Catalin Marinas189d84e2009-08-27 14:29:15 +0100406 pr_notice(" flags = 0x%lx\n", object->flags);
Jianpeng Maaae0ad72014-06-06 14:38:16 -0700407 pr_notice(" checksum = %u\n", object->checksum);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100408 pr_notice(" backtrace:\n");
409 print_stack_trace(&trace, 4);
410}
411
412/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700413 * Look-up a memory block metadata (kmemleak_object) in the object search
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100414 * tree based on a pointer value. If alias is 0, only values pointing to the
415 * beginning of the memory block are allowed. The kmemleak_lock must be held
416 * when calling this function.
417 */
418static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
419{
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700420 struct rb_node *rb = object_tree_root.rb_node;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100421
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700422 while (rb) {
423 struct kmemleak_object *object =
424 rb_entry(rb, struct kmemleak_object, rb_node);
425 if (ptr < object->pointer)
426 rb = object->rb_node.rb_left;
427 else if (object->pointer + object->size <= ptr)
428 rb = object->rb_node.rb_right;
429 else if (object->pointer == ptr || alias)
430 return object;
431 else {
Catalin Marinas5f790202011-09-28 12:17:03 +0100432 kmemleak_warn("Found object by alias at 0x%08lx\n",
433 ptr);
Catalin Marinasa7686a42010-07-19 11:54:16 +0100434 dump_object_info(object);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700435 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100436 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700437 }
438 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100439}
440
441/*
442 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note
443 * that once an object's use_count reached 0, the RCU freeing was already
444 * registered and the object should no longer be used. This function must be
445 * called under the protection of rcu_read_lock().
446 */
447static int get_object(struct kmemleak_object *object)
448{
449 return atomic_inc_not_zero(&object->use_count);
450}
451
452/*
453 * RCU callback to free a kmemleak_object.
454 */
455static void free_object_rcu(struct rcu_head *rcu)
456{
Sasha Levinb67bfe02013-02-27 17:06:00 -0800457 struct hlist_node *tmp;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100458 struct kmemleak_scan_area *area;
459 struct kmemleak_object *object =
460 container_of(rcu, struct kmemleak_object, rcu);
461
462 /*
463 * Once use_count is 0 (guaranteed by put_object), there is no other
464 * code accessing this object, hence no need for locking.
465 */
Sasha Levinb67bfe02013-02-27 17:06:00 -0800466 hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
467 hlist_del(&area->node);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100468 kmem_cache_free(scan_area_cache, area);
469 }
470 kmem_cache_free(object_cache, object);
471}
472
473/*
474 * Decrement the object use_count. Once the count is 0, free the object using
475 * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
476 * delete_object() path, the delayed RCU freeing ensures that there is no
477 * recursive call to the kernel allocator. Lock-less RCU object_list traversal
478 * is also possible.
479 */
480static void put_object(struct kmemleak_object *object)
481{
482 if (!atomic_dec_and_test(&object->use_count))
483 return;
484
485 /* should only get here after delete_object was called */
486 WARN_ON(object->flags & OBJECT_ALLOCATED);
487
488 call_rcu(&object->rcu, free_object_rcu);
489}
490
491/*
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700492 * Look up an object in the object search tree and increase its use_count.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100493 */
494static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
495{
496 unsigned long flags;
Alexey Klimov9fbed252015-11-05 18:45:57 -0800497 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100498
499 rcu_read_lock();
500 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -0700501 object = lookup_object(ptr, alias);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100502 read_unlock_irqrestore(&kmemleak_lock, flags);
503
504 /* check whether the object is still available */
505 if (object && !get_object(object))
506 object = NULL;
507 rcu_read_unlock();
508
509 return object;
510}
511
512/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700513 * Look up an object in the object search tree and remove it from both
514 * object_tree_root and object_list. The returned object's use_count should be
515 * at least 1, as initially set by create_object().
516 */
517static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
518{
519 unsigned long flags;
520 struct kmemleak_object *object;
521
522 write_lock_irqsave(&kmemleak_lock, flags);
523 object = lookup_object(ptr, alias);
524 if (object) {
525 rb_erase(&object->rb_node, &object_tree_root);
526 list_del_rcu(&object->object_list);
527 }
528 write_unlock_irqrestore(&kmemleak_lock, flags);
529
530 return object;
531}
532
533/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100534 * Save stack trace to the given array of MAX_TRACE size.
535 */
536static int __save_stack_trace(unsigned long *trace)
537{
538 struct stack_trace stack_trace;
539
540 stack_trace.max_entries = MAX_TRACE;
541 stack_trace.nr_entries = 0;
542 stack_trace.entries = trace;
543 stack_trace.skip = 2;
544 save_stack_trace(&stack_trace);
545
546 return stack_trace.nr_entries;
547}
548
549/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100550 * Create the metadata (struct kmemleak_object) corresponding to an allocated
551 * memory block and add it to the object_list and object_tree_root.
552 */
Catalin Marinasfd678962009-08-27 14:29:17 +0100553static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
554 int min_count, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100555{
556 unsigned long flags;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700557 struct kmemleak_object *object, *parent;
558 struct rb_node **link, *rb_parent;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100559
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000560 object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100561 if (!object) {
Joe Perches598d8092016-03-17 14:19:44 -0700562 pr_warn("Cannot allocate a kmemleak_object structure\n");
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000563 kmemleak_disable();
Catalin Marinasfd678962009-08-27 14:29:17 +0100564 return NULL;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100565 }
566
567 INIT_LIST_HEAD(&object->object_list);
568 INIT_LIST_HEAD(&object->gray_list);
569 INIT_HLIST_HEAD(&object->area_list);
570 spin_lock_init(&object->lock);
571 atomic_set(&object->use_count, 1);
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000572 object->flags = OBJECT_ALLOCATED;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100573 object->pointer = ptr;
574 object->size = size;
575 object->min_count = min_count;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000576 object->count = 0; /* white color initially */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100577 object->jiffies = jiffies;
Catalin Marinas04609ccc2009-10-28 13:33:12 +0000578 object->checksum = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100579
580 /* task information */
581 if (in_irq()) {
582 object->pid = 0;
583 strncpy(object->comm, "hardirq", sizeof(object->comm));
584 } else if (in_softirq()) {
585 object->pid = 0;
586 strncpy(object->comm, "softirq", sizeof(object->comm));
587 } else {
588 object->pid = current->pid;
589 /*
590 * There is a small chance of a race with set_task_comm(),
591 * however using get_task_comm() here may cause locking
592 * dependency issues with current->alloc_lock. In the worst
593 * case, the command line is not correct.
594 */
595 strncpy(object->comm, current->comm, sizeof(object->comm));
596 }
597
598 /* kernel backtrace */
Catalin Marinasfd678962009-08-27 14:29:17 +0100599 object->trace_len = __save_stack_trace(object->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100600
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100601 write_lock_irqsave(&kmemleak_lock, flags);
Luis R. Rodriguez0580a182009-09-08 17:32:34 +0100602
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100603 min_addr = min(min_addr, ptr);
604 max_addr = max(max_addr, ptr + size);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700605 link = &object_tree_root.rb_node;
606 rb_parent = NULL;
607 while (*link) {
608 rb_parent = *link;
609 parent = rb_entry(rb_parent, struct kmemleak_object, rb_node);
610 if (ptr + size <= parent->pointer)
611 link = &parent->rb_node.rb_left;
612 else if (parent->pointer + parent->size <= ptr)
613 link = &parent->rb_node.rb_right;
614 else {
Joe Perches756a025f02016-03-17 14:19:47 -0700615 kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700616 ptr);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700617 /*
618 * No need for parent->lock here since "parent" cannot
619 * be freed while the kmemleak_lock is held.
620 */
621 dump_object_info(parent);
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700622 kmem_cache_free(object_cache, object);
Catalin Marinas9d5a4c72015-06-24 16:58:34 -0700623 object = NULL;
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700624 goto out;
625 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100626 }
Michel Lespinasse85d3a312012-10-08 16:31:27 -0700627 rb_link_node(&object->rb_node, rb_parent, link);
628 rb_insert_color(&object->rb_node, &object_tree_root);
629
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100630 list_add_tail_rcu(&object->object_list, &object_list);
631out:
632 write_unlock_irqrestore(&kmemleak_lock, flags);
Catalin Marinasfd678962009-08-27 14:29:17 +0100633 return object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100634}
635
636/*
Catalin Marinase781a9a2015-06-24 16:58:29 -0700637 * Mark the object as not allocated and schedule RCU freeing via put_object().
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100638 */
Catalin Marinas53238a62009-07-07 10:33:00 +0100639static void __delete_object(struct kmemleak_object *object)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100640{
641 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100642
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100643 WARN_ON(!(object->flags & OBJECT_ALLOCATED));
Catalin Marinase781a9a2015-06-24 16:58:29 -0700644 WARN_ON(atomic_read(&object->use_count) < 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100645
646 /*
647 * Locking here also ensures that the corresponding memory block
648 * cannot be freed when it is being scanned.
649 */
650 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100651 object->flags &= ~OBJECT_ALLOCATED;
652 spin_unlock_irqrestore(&object->lock, flags);
653 put_object(object);
654}
655
656/*
Catalin Marinas53238a62009-07-07 10:33:00 +0100657 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
658 * delete it.
659 */
660static void delete_object_full(unsigned long ptr)
661{
662 struct kmemleak_object *object;
663
Catalin Marinase781a9a2015-06-24 16:58:29 -0700664 object = find_and_remove_object(ptr, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100665 if (!object) {
666#ifdef DEBUG
667 kmemleak_warn("Freeing unknown object at 0x%08lx\n",
668 ptr);
669#endif
670 return;
671 }
672 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100673}
674
675/*
676 * Look up the metadata (struct kmemleak_object) corresponding to ptr and
677 * delete it. If the memory block is partially freed, the function may create
678 * additional metadata for the remaining parts of the block.
679 */
680static void delete_object_part(unsigned long ptr, size_t size)
681{
682 struct kmemleak_object *object;
683 unsigned long start, end;
684
Catalin Marinase781a9a2015-06-24 16:58:29 -0700685 object = find_and_remove_object(ptr, 1);
Catalin Marinas53238a62009-07-07 10:33:00 +0100686 if (!object) {
687#ifdef DEBUG
Joe Perches756a025f02016-03-17 14:19:47 -0700688 kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n",
689 ptr, size);
Catalin Marinas53238a62009-07-07 10:33:00 +0100690#endif
691 return;
692 }
Catalin Marinas53238a62009-07-07 10:33:00 +0100693
694 /*
695 * Create one or two objects that may result from the memory block
696 * split. Note that partial freeing is only done by free_bootmem() and
697 * this happens before kmemleak_init() is called. The path below is
698 * only executed during early log recording in kmemleak_init(), so
699 * GFP_KERNEL is enough.
700 */
701 start = object->pointer;
702 end = object->pointer + object->size;
703 if (ptr > start)
704 create_object(start, ptr - start, object->min_count,
705 GFP_KERNEL);
706 if (ptr + size < end)
707 create_object(ptr + size, end - ptr - size, object->min_count,
708 GFP_KERNEL);
709
Catalin Marinase781a9a2015-06-24 16:58:29 -0700710 __delete_object(object);
Catalin Marinas53238a62009-07-07 10:33:00 +0100711}
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700712
713static void __paint_it(struct kmemleak_object *object, int color)
714{
715 object->min_count = color;
716 if (color == KMEMLEAK_BLACK)
717 object->flags |= OBJECT_NO_SCAN;
718}
719
720static void paint_it(struct kmemleak_object *object, int color)
721{
722 unsigned long flags;
723
724 spin_lock_irqsave(&object->lock, flags);
725 __paint_it(object, color);
726 spin_unlock_irqrestore(&object->lock, flags);
727}
728
729static void paint_ptr(unsigned long ptr, int color)
730{
731 struct kmemleak_object *object;
732
733 object = find_and_get_object(ptr, 0);
734 if (!object) {
Joe Perches756a025f02016-03-17 14:19:47 -0700735 kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
736 ptr,
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700737 (color == KMEMLEAK_GREY) ? "Grey" :
738 (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
739 return;
740 }
741 paint_it(object, color);
742 put_object(object);
743}
744
Catalin Marinas53238a62009-07-07 10:33:00 +0100745/*
Holger Hans Peter Freyther145b64b2010-07-22 19:54:13 +0800746 * Mark an object permanently as gray-colored so that it can no longer be
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100747 * reported as a leak. This is used in general to mark a false positive.
748 */
749static void make_gray_object(unsigned long ptr)
750{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700751 paint_ptr(ptr, KMEMLEAK_GREY);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100752}
753
754/*
755 * Mark the object as black-colored so that it is ignored from scans and
756 * reporting.
757 */
758static void make_black_object(unsigned long ptr)
759{
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -0700760 paint_ptr(ptr, KMEMLEAK_BLACK);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100761}
762
763/*
764 * Add a scanning area to the object. If at least one such area is added,
765 * kmemleak will only scan these ranges rather than the whole memory block.
766 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000767static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100768{
769 unsigned long flags;
770 struct kmemleak_object *object;
771 struct kmemleak_scan_area *area;
772
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000773 object = find_and_get_object(ptr, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100774 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100775 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
776 ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100777 return;
778 }
779
Catalin Marinas6ae4bd12011-01-27 10:30:26 +0000780 area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100781 if (!area) {
Joe Perches598d8092016-03-17 14:19:44 -0700782 pr_warn("Cannot allocate a scan area\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100783 goto out;
784 }
785
786 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas7f88f882013-11-12 15:07:45 -0800787 if (size == SIZE_MAX) {
788 size = object->pointer + object->size - ptr;
789 } else if (ptr + size > object->pointer + object->size) {
Joe Perchesae281062009-06-23 14:40:26 +0100790 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100791 dump_object_info(object);
792 kmem_cache_free(scan_area_cache, area);
793 goto out_unlock;
794 }
795
796 INIT_HLIST_NODE(&area->node);
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000797 area->start = ptr;
798 area->size = size;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100799
800 hlist_add_head(&area->node, &object->area_list);
801out_unlock:
802 spin_unlock_irqrestore(&object->lock, flags);
803out:
804 put_object(object);
805}
806
807/*
808 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
809 * pointer. Such object will not be scanned by kmemleak but references to it
810 * are searched.
811 */
812static void object_no_scan(unsigned long ptr)
813{
814 unsigned long flags;
815 struct kmemleak_object *object;
816
817 object = find_and_get_object(ptr, 0);
818 if (!object) {
Joe Perchesae281062009-06-23 14:40:26 +0100819 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100820 return;
821 }
822
823 spin_lock_irqsave(&object->lock, flags);
824 object->flags |= OBJECT_NO_SCAN;
825 spin_unlock_irqrestore(&object->lock, flags);
826 put_object(object);
827}
828
829/*
830 * Log an early kmemleak_* call to the early_log buffer. These calls will be
831 * processed later once kmemleak is fully initialized.
832 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100833static void __init log_early(int op_type, const void *ptr, size_t size,
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000834 int min_count)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100835{
836 unsigned long flags;
837 struct early_log *log;
838
Li Zefan8910ae82014-04-03 14:46:29 -0700839 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +0100840 /* kmemleak stopped recording, just count the requests */
841 crt_early_log++;
842 return;
843 }
844
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100845 if (crt_early_log >= ARRAY_SIZE(early_log)) {
Wang Kai21cd3a62015-09-08 15:03:41 -0700846 crt_early_log++;
Catalin Marinasa9d90582009-06-25 10:16:11 +0100847 kmemleak_disable();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100848 return;
849 }
850
851 /*
852 * There is no need for locking since the kernel is still in UP mode
853 * at this stage. Disabling the IRQs is enough.
854 */
855 local_irq_save(flags);
856 log = &early_log[crt_early_log];
857 log->op_type = op_type;
858 log->ptr = ptr;
859 log->size = size;
860 log->min_count = min_count;
Catalin Marinas5f790202011-09-28 12:17:03 +0100861 log->trace_len = __save_stack_trace(log->trace);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100862 crt_early_log++;
863 local_irq_restore(flags);
864}
865
866/*
Catalin Marinasfd678962009-08-27 14:29:17 +0100867 * Log an early allocated block and populate the stack trace.
868 */
869static void early_alloc(struct early_log *log)
870{
871 struct kmemleak_object *object;
872 unsigned long flags;
873 int i;
874
Li Zefan8910ae82014-04-03 14:46:29 -0700875 if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
Catalin Marinasfd678962009-08-27 14:29:17 +0100876 return;
877
878 /*
879 * RCU locking needed to ensure object is not freed via put_object().
880 */
881 rcu_read_lock();
882 object = create_object((unsigned long)log->ptr, log->size,
Tetsuo Handac1bcd6b2009-10-09 10:39:24 +0100883 log->min_count, GFP_ATOMIC);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100884 if (!object)
885 goto out;
Catalin Marinasfd678962009-08-27 14:29:17 +0100886 spin_lock_irqsave(&object->lock, flags);
887 for (i = 0; i < log->trace_len; i++)
888 object->trace[i] = log->trace[i];
889 object->trace_len = log->trace_len;
890 spin_unlock_irqrestore(&object->lock, flags);
Catalin Marinas0d5d1aa2009-10-09 10:30:34 +0100891out:
Catalin Marinasfd678962009-08-27 14:29:17 +0100892 rcu_read_unlock();
893}
894
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100895/*
896 * Log an early allocated block and populate the stack trace.
897 */
898static void early_alloc_percpu(struct early_log *log)
899{
900 unsigned int cpu;
901 const void __percpu *ptr = log->ptr;
902
903 for_each_possible_cpu(cpu) {
904 log->ptr = per_cpu_ptr(ptr, cpu);
905 early_alloc(log);
906 }
907}
908
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100909/**
910 * kmemleak_alloc - register a newly allocated object
911 * @ptr: pointer to beginning of the object
912 * @size: size of the object
913 * @min_count: minimum number of references to this object. If during memory
914 * scanning a number of references less than @min_count is found,
915 * the object is reported as a memory leak. If @min_count is 0,
916 * the object is never reported as a leak. If @min_count is -1,
917 * the object is ignored (not scanned and not reported as a leak)
918 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
919 *
920 * This function is called from the kernel allocators when a new object
921 * (memory block) is allocated (kmem_cache_alloc, kmalloc, vmalloc etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100922 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100923void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
924 gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100925{
926 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
927
Li Zefan8910ae82014-04-03 14:46:29 -0700928 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100929 create_object((unsigned long)ptr, size, min_count, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700930 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000931 log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100932}
933EXPORT_SYMBOL_GPL(kmemleak_alloc);
934
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100935/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100936 * kmemleak_alloc_percpu - register a newly allocated __percpu object
937 * @ptr: __percpu pointer to beginning of the object
938 * @size: size of the object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700939 * @gfp: flags used for kmemleak internal memory allocations
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100940 *
941 * This function is called from the kernel percpu allocator when a new object
Larry Finger8a8c35f2015-06-24 16:58:51 -0700942 * (memory block) is allocated (alloc_percpu).
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100943 */
Larry Finger8a8c35f2015-06-24 16:58:51 -0700944void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size,
945 gfp_t gfp)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100946{
947 unsigned int cpu;
948
949 pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
950
951 /*
952 * Percpu allocations are only scanned and not reported as leaks
953 * (min_count is set to 0).
954 */
Li Zefan8910ae82014-04-03 14:46:29 -0700955 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100956 for_each_possible_cpu(cpu)
957 create_object((unsigned long)per_cpu_ptr(ptr, cpu),
Larry Finger8a8c35f2015-06-24 16:58:51 -0700958 size, 0, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -0700959 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +0100960 log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
961}
962EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
963
964/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100965 * kmemleak_free - unregister a previously registered object
966 * @ptr: pointer to beginning of the object
967 *
968 * This function is called from the kernel allocators when an object (memory
969 * block) is freed (kmem_cache_free, kfree, vfree etc.).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100970 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100971void __ref kmemleak_free(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100972{
973 pr_debug("%s(0x%p)\n", __func__, ptr);
974
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -0700975 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +0100976 delete_object_full((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -0700977 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000978 log_early(KMEMLEAK_FREE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +0100979}
980EXPORT_SYMBOL_GPL(kmemleak_free);
981
Catalin Marinasa2b6bf62010-07-19 11:54:17 +0100982/**
983 * kmemleak_free_part - partially unregister a previously registered object
984 * @ptr: pointer to the beginning or inside the object. This also
985 * represents the start of the range to be freed
986 * @size: size to be unregistered
987 *
988 * This function is called when only a part of a memory block is freed
989 * (usually from the bootmem allocator).
Catalin Marinas53238a62009-07-07 10:33:00 +0100990 */
Catalin Marinasa6186d82009-08-27 14:29:16 +0100991void __ref kmemleak_free_part(const void *ptr, size_t size)
Catalin Marinas53238a62009-07-07 10:33:00 +0100992{
993 pr_debug("%s(0x%p)\n", __func__, ptr);
994
Li Zefan8910ae82014-04-03 14:46:29 -0700995 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas53238a62009-07-07 10:33:00 +0100996 delete_object_part((unsigned long)ptr, size);
Li Zefan8910ae82014-04-03 14:46:29 -0700997 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +0000998 log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
Catalin Marinas53238a62009-07-07 10:33:00 +0100999}
1000EXPORT_SYMBOL_GPL(kmemleak_free_part);
1001
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001002/**
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001003 * kmemleak_free_percpu - unregister a previously registered __percpu object
1004 * @ptr: __percpu pointer to beginning of the object
1005 *
1006 * This function is called from the kernel percpu allocator when an object
1007 * (memory block) is freed (free_percpu).
1008 */
1009void __ref kmemleak_free_percpu(const void __percpu *ptr)
1010{
1011 unsigned int cpu;
1012
1013 pr_debug("%s(0x%p)\n", __func__, ptr);
1014
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001015 if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001016 for_each_possible_cpu(cpu)
1017 delete_object_full((unsigned long)per_cpu_ptr(ptr,
1018 cpu));
Li Zefan8910ae82014-04-03 14:46:29 -07001019 else if (kmemleak_early_log)
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001020 log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
1021}
1022EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
1023
1024/**
Catalin Marinasffe2c742014-06-06 14:38:17 -07001025 * kmemleak_update_trace - update object allocation stack trace
1026 * @ptr: pointer to beginning of the object
1027 *
1028 * Override the object allocation stack trace for cases where the actual
1029 * allocation place is not always useful.
1030 */
1031void __ref kmemleak_update_trace(const void *ptr)
1032{
1033 struct kmemleak_object *object;
1034 unsigned long flags;
1035
1036 pr_debug("%s(0x%p)\n", __func__, ptr);
1037
1038 if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
1039 return;
1040
1041 object = find_and_get_object((unsigned long)ptr, 1);
1042 if (!object) {
1043#ifdef DEBUG
1044 kmemleak_warn("Updating stack trace for unknown object at %p\n",
1045 ptr);
1046#endif
1047 return;
1048 }
1049
1050 spin_lock_irqsave(&object->lock, flags);
1051 object->trace_len = __save_stack_trace(object->trace);
1052 spin_unlock_irqrestore(&object->lock, flags);
1053
1054 put_object(object);
1055}
1056EXPORT_SYMBOL(kmemleak_update_trace);
1057
1058/**
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001059 * kmemleak_not_leak - mark an allocated object as false positive
1060 * @ptr: pointer to beginning of the object
1061 *
1062 * Calling this function on an object will cause the memory block to no longer
1063 * be reported as leak and always be scanned.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001064 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001065void __ref kmemleak_not_leak(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001066{
1067 pr_debug("%s(0x%p)\n", __func__, ptr);
1068
Li Zefan8910ae82014-04-03 14:46:29 -07001069 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001070 make_gray_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001071 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001072 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001073}
1074EXPORT_SYMBOL(kmemleak_not_leak);
1075
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001076/**
1077 * kmemleak_ignore - ignore an allocated object
1078 * @ptr: pointer to beginning of the object
1079 *
1080 * Calling this function on an object will cause the memory block to be
1081 * ignored (not scanned and not reported as a leak). This is usually done when
1082 * it is known that the corresponding block is not a leak and does not contain
1083 * any references to other allocated memory blocks.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001084 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001085void __ref kmemleak_ignore(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001086{
1087 pr_debug("%s(0x%p)\n", __func__, ptr);
1088
Li Zefan8910ae82014-04-03 14:46:29 -07001089 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001090 make_black_object((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001091 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001092 log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001093}
1094EXPORT_SYMBOL(kmemleak_ignore);
1095
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001096/**
1097 * kmemleak_scan_area - limit the range to be scanned in an allocated object
1098 * @ptr: pointer to beginning or inside the object. This also
1099 * represents the start of the scan area
1100 * @size: size of the scan area
1101 * @gfp: kmalloc() flags used for kmemleak internal memory allocations
1102 *
1103 * This function is used when it is known that only certain parts of an object
1104 * contain references to other objects. Kmemleak will only scan these areas
1105 * reducing the number false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001106 */
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001107void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001108{
1109 pr_debug("%s(0x%p)\n", __func__, ptr);
1110
Li Zefan8910ae82014-04-03 14:46:29 -07001111 if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001112 add_scan_area((unsigned long)ptr, size, gfp);
Li Zefan8910ae82014-04-03 14:46:29 -07001113 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001114 log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001115}
1116EXPORT_SYMBOL(kmemleak_scan_area);
1117
Catalin Marinasa2b6bf62010-07-19 11:54:17 +01001118/**
1119 * kmemleak_no_scan - do not scan an allocated object
1120 * @ptr: pointer to beginning of the object
1121 *
1122 * This function notifies kmemleak not to scan the given memory block. Useful
1123 * in situations where it is known that the given object does not contain any
1124 * references to other objects. Kmemleak will not scan such objects reducing
1125 * the number of false negatives.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001126 */
Catalin Marinasa6186d82009-08-27 14:29:16 +01001127void __ref kmemleak_no_scan(const void *ptr)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001128{
1129 pr_debug("%s(0x%p)\n", __func__, ptr);
1130
Li Zefan8910ae82014-04-03 14:46:29 -07001131 if (kmemleak_enabled && ptr && !IS_ERR(ptr))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001132 object_no_scan((unsigned long)ptr);
Li Zefan8910ae82014-04-03 14:46:29 -07001133 else if (kmemleak_early_log)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001134 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001135}
1136EXPORT_SYMBOL(kmemleak_no_scan);
1137
Catalin Marinas9099dae2016-10-11 13:55:11 -07001138/**
1139 * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
1140 * address argument
1141 */
1142void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
1143 gfp_t gfp)
1144{
1145 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1146 kmemleak_alloc(__va(phys), size, min_count, gfp);
1147}
1148EXPORT_SYMBOL(kmemleak_alloc_phys);
1149
1150/**
1151 * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
1152 * physical address argument
1153 */
1154void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
1155{
1156 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1157 kmemleak_free_part(__va(phys), size);
1158}
1159EXPORT_SYMBOL(kmemleak_free_part_phys);
1160
1161/**
1162 * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
1163 * address argument
1164 */
1165void __ref kmemleak_not_leak_phys(phys_addr_t phys)
1166{
1167 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1168 kmemleak_not_leak(__va(phys));
1169}
1170EXPORT_SYMBOL(kmemleak_not_leak_phys);
1171
1172/**
1173 * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
1174 * address argument
1175 */
1176void __ref kmemleak_ignore_phys(phys_addr_t phys)
1177{
1178 if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
1179 kmemleak_ignore(__va(phys));
1180}
1181EXPORT_SYMBOL(kmemleak_ignore_phys);
1182
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001183/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001184 * Update an object's checksum and return true if it was modified.
1185 */
1186static bool update_checksum(struct kmemleak_object *object)
1187{
1188 u32 old_csum = object->checksum;
1189
1190 if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
1191 return false;
1192
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001193 kasan_disable_current();
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001194 object->checksum = crc32(0, (void *)object->pointer, object->size);
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001195 kasan_enable_current();
1196
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001197 return object->checksum != old_csum;
1198}
1199
1200/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001201 * Memory scanning is a long process and it needs to be interruptable. This
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001202 * function checks whether such interrupt condition occurred.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001203 */
1204static int scan_should_stop(void)
1205{
Li Zefan8910ae82014-04-03 14:46:29 -07001206 if (!kmemleak_enabled)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001207 return 1;
1208
1209 /*
1210 * This function may be called from either process or kthread context,
1211 * hence the need to check for both stop conditions.
1212 */
1213 if (current->mm)
1214 return signal_pending(current);
1215 else
1216 return kthread_should_stop();
1217
1218 return 0;
1219}
1220
1221/*
1222 * Scan a memory block (exclusive range) for valid pointers and add those
1223 * found to the gray list.
1224 */
1225static void scan_block(void *_start, void *_end,
Catalin Marinas93ada572015-06-24 16:58:37 -07001226 struct kmemleak_object *scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001227{
1228 unsigned long *ptr;
1229 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
1230 unsigned long *end = _end - (BYTES_PER_POINTER - 1);
Catalin Marinas93ada572015-06-24 16:58:37 -07001231 unsigned long flags;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001232
Catalin Marinas93ada572015-06-24 16:58:37 -07001233 read_lock_irqsave(&kmemleak_lock, flags);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001234 for (ptr = start; ptr < end; ptr++) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001235 struct kmemleak_object *object;
Pekka Enberg8e019362009-08-27 14:50:00 +01001236 unsigned long pointer;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001237
1238 if (scan_should_stop())
1239 break;
1240
Pekka Enberg8e019362009-08-27 14:50:00 +01001241 /* don't scan uninitialized memory */
1242 if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
1243 BYTES_PER_POINTER))
1244 continue;
1245
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001246 kasan_disable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001247 pointer = *ptr;
Andrey Ryabinine79ed2f2015-02-13 14:39:49 -08001248 kasan_enable_current();
Pekka Enberg8e019362009-08-27 14:50:00 +01001249
Catalin Marinas93ada572015-06-24 16:58:37 -07001250 if (pointer < min_addr || pointer >= max_addr)
1251 continue;
1252
1253 /*
1254 * No need for get_object() here since we hold kmemleak_lock.
1255 * object->use_count cannot be dropped to 0 while the object
1256 * is still present in object_tree_root and object_list
1257 * (with updates protected by kmemleak_lock).
1258 */
1259 object = lookup_object(pointer, 1);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001260 if (!object)
1261 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001262 if (object == scanned)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001263 /* self referenced, ignore */
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001264 continue;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001265
1266 /*
1267 * Avoid the lockdep recursive warning on object->lock being
1268 * previously acquired in scan_object(). These locks are
1269 * enclosed by scan_mutex.
1270 */
Catalin Marinas93ada572015-06-24 16:58:37 -07001271 spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001272 if (!color_white(object)) {
1273 /* non-orphan, ignored or new */
Catalin Marinas93ada572015-06-24 16:58:37 -07001274 spin_unlock(&object->lock);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001275 continue;
1276 }
1277
1278 /*
1279 * Increase the object's reference count (number of pointers
1280 * to the memory block). If this count reaches the required
1281 * minimum, the object's color will become gray and it will be
1282 * added to the gray_list.
1283 */
1284 object->count++;
Catalin Marinas0587da42009-10-28 13:33:11 +00001285 if (color_gray(object)) {
Catalin Marinas93ada572015-06-24 16:58:37 -07001286 /* put_object() called when removing from gray_list */
1287 WARN_ON(!get_object(object));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001288 list_add_tail(&object->gray_list, &gray_list);
Catalin Marinas0587da42009-10-28 13:33:11 +00001289 }
Catalin Marinas93ada572015-06-24 16:58:37 -07001290 spin_unlock(&object->lock);
1291 }
1292 read_unlock_irqrestore(&kmemleak_lock, flags);
1293}
Catalin Marinas0587da42009-10-28 13:33:11 +00001294
Catalin Marinas93ada572015-06-24 16:58:37 -07001295/*
1296 * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
1297 */
1298static void scan_large_block(void *start, void *end)
1299{
1300 void *next;
1301
1302 while (start < end) {
1303 next = min(start + MAX_SCAN_SIZE, end);
1304 scan_block(start, next, NULL);
1305 start = next;
1306 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001307 }
1308}
1309
1310/*
1311 * Scan a memory block corresponding to a kmemleak_object. A condition is
1312 * that object->use_count >= 1.
1313 */
1314static void scan_object(struct kmemleak_object *object)
1315{
1316 struct kmemleak_scan_area *area;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001317 unsigned long flags;
1318
1319 /*
Uwe Kleine-König21ae2952009-10-07 15:21:09 +02001320 * Once the object->lock is acquired, the corresponding memory block
1321 * cannot be freed (the same lock is acquired in delete_object).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001322 */
1323 spin_lock_irqsave(&object->lock, flags);
1324 if (object->flags & OBJECT_NO_SCAN)
1325 goto out;
1326 if (!(object->flags & OBJECT_ALLOCATED))
1327 /* already freed object */
1328 goto out;
Catalin Marinasaf986032009-08-27 14:29:12 +01001329 if (hlist_empty(&object->area_list)) {
1330 void *start = (void *)object->pointer;
1331 void *end = (void *)(object->pointer + object->size);
Catalin Marinas93ada572015-06-24 16:58:37 -07001332 void *next;
Catalin Marinasaf986032009-08-27 14:29:12 +01001333
Catalin Marinas93ada572015-06-24 16:58:37 -07001334 do {
1335 next = min(start + MAX_SCAN_SIZE, end);
1336 scan_block(start, next, object);
1337
1338 start = next;
1339 if (start >= end)
1340 break;
Catalin Marinasaf986032009-08-27 14:29:12 +01001341
1342 spin_unlock_irqrestore(&object->lock, flags);
1343 cond_resched();
1344 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas93ada572015-06-24 16:58:37 -07001345 } while (object->flags & OBJECT_ALLOCATED);
Catalin Marinasaf986032009-08-27 14:29:12 +01001346 } else
Sasha Levinb67bfe02013-02-27 17:06:00 -08001347 hlist_for_each_entry(area, &object->area_list, node)
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001348 scan_block((void *)area->start,
1349 (void *)(area->start + area->size),
Catalin Marinas93ada572015-06-24 16:58:37 -07001350 object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001351out:
1352 spin_unlock_irqrestore(&object->lock, flags);
1353}
1354
1355/*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001356 * Scan the objects already referenced (gray objects). More objects will be
1357 * referenced and, if there are no memory leaks, all the objects are scanned.
1358 */
1359static void scan_gray_list(void)
1360{
1361 struct kmemleak_object *object, *tmp;
1362
1363 /*
1364 * The list traversal is safe for both tail additions and removals
1365 * from inside the loop. The kmemleak objects cannot be freed from
1366 * outside the loop because their use_count was incremented.
1367 */
1368 object = list_entry(gray_list.next, typeof(*object), gray_list);
1369 while (&object->gray_list != &gray_list) {
1370 cond_resched();
1371
1372 /* may add new objects to the list */
1373 if (!scan_should_stop())
1374 scan_object(object);
1375
1376 tmp = list_entry(object->gray_list.next, typeof(*object),
1377 gray_list);
1378
1379 /* remove the object from the list and release it */
1380 list_del(&object->gray_list);
1381 put_object(object);
1382
1383 object = tmp;
1384 }
1385 WARN_ON(!list_empty(&gray_list));
1386}
1387
1388/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001389 * Scan data sections and all the referenced memory blocks allocated via the
1390 * kernel's standard allocators. This function must be called with the
1391 * scan_mutex held.
1392 */
1393static void kmemleak_scan(void)
1394{
1395 unsigned long flags;
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001396 struct kmemleak_object *object;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001397 int i;
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001398 int new_leaks = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001399
Catalin Marinasacf49682009-06-26 17:38:29 +01001400 jiffies_last_scan = jiffies;
1401
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001402 /* prepare the kmemleak_object's */
1403 rcu_read_lock();
1404 list_for_each_entry_rcu(object, &object_list, object_list) {
1405 spin_lock_irqsave(&object->lock, flags);
1406#ifdef DEBUG
1407 /*
1408 * With a few exceptions there should be a maximum of
1409 * 1 reference to any object at this point.
1410 */
1411 if (atomic_read(&object->use_count) > 1) {
Joe Perchesae281062009-06-23 14:40:26 +01001412 pr_debug("object->use_count = %d\n",
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001413 atomic_read(&object->use_count));
1414 dump_object_info(object);
1415 }
1416#endif
1417 /* reset the reference count (whiten the object) */
1418 object->count = 0;
1419 if (color_gray(object) && get_object(object))
1420 list_add_tail(&object->gray_list, &gray_list);
1421
1422 spin_unlock_irqrestore(&object->lock, flags);
1423 }
1424 rcu_read_unlock();
1425
1426 /* data/bss scanning */
Catalin Marinas93ada572015-06-24 16:58:37 -07001427 scan_large_block(_sdata, _edata);
1428 scan_large_block(__bss_start, __bss_stop);
Jakub Kicinskid7c19b02016-11-10 10:46:44 -08001429 scan_large_block(__start_data_ro_after_init, __end_data_ro_after_init);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001430
1431#ifdef CONFIG_SMP
1432 /* per-cpu sections scanning */
1433 for_each_possible_cpu(i)
Catalin Marinas93ada572015-06-24 16:58:37 -07001434 scan_large_block(__per_cpu_start + per_cpu_offset(i),
1435 __per_cpu_end + per_cpu_offset(i));
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001436#endif
1437
1438 /*
Laura Abbott029aeff2011-11-15 23:49:09 +00001439 * Struct page scanning for each node.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001440 */
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001441 get_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001442 for_each_online_node(i) {
Cody P Schafer108bcc92013-02-22 16:35:23 -08001443 unsigned long start_pfn = node_start_pfn(i);
1444 unsigned long end_pfn = node_end_pfn(i);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001445 unsigned long pfn;
1446
1447 for (pfn = start_pfn; pfn < end_pfn; pfn++) {
1448 struct page *page;
1449
1450 if (!pfn_valid(pfn))
1451 continue;
1452 page = pfn_to_page(pfn);
1453 /* only scan if page is in use */
1454 if (page_count(page) == 0)
1455 continue;
Catalin Marinas93ada572015-06-24 16:58:37 -07001456 scan_block(page, page + 1, NULL);
Yisheng Xie7b862382017-11-29 16:11:08 -08001457 if (!(pfn % (MAX_SCAN_SIZE / sizeof(*page))))
1458 cond_resched();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001459 }
1460 }
Vladimir Davydovbfc8c902014-06-04 16:07:18 -07001461 put_online_mems();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001462
1463 /*
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001464 * Scanning the task stacks (may introduce false negatives).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001465 */
1466 if (kmemleak_stack_scan) {
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001467 struct task_struct *p, *g;
1468
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001469 read_lock(&tasklist_lock);
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001470 do_each_thread(g, p) {
Catalin Marinas37df49f2016-10-27 17:46:47 -07001471 void *stack = try_get_task_stack(p);
1472 if (stack) {
1473 scan_block(stack, stack + THREAD_SIZE, NULL);
1474 put_task_stack(p);
1475 }
Catalin Marinas43ed5d62009-09-01 11:12:44 +01001476 } while_each_thread(g, p);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001477 read_unlock(&tasklist_lock);
1478 }
1479
1480 /*
1481 * Scan the objects already referenced from the sections scanned
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001482 * above.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001483 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001484 scan_gray_list();
Catalin Marinas25873622009-07-07 10:32:58 +01001485
1486 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001487 * Check for new or unreferenced objects modified since the previous
1488 * scan and color them gray until the next scan.
Catalin Marinas25873622009-07-07 10:32:58 +01001489 */
1490 rcu_read_lock();
1491 list_for_each_entry_rcu(object, &object_list, object_list) {
1492 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001493 if (color_white(object) && (object->flags & OBJECT_ALLOCATED)
1494 && update_checksum(object) && get_object(object)) {
1495 /* color it gray temporarily */
1496 object->count = object->min_count;
Catalin Marinas25873622009-07-07 10:32:58 +01001497 list_add_tail(&object->gray_list, &gray_list);
1498 }
1499 spin_unlock_irqrestore(&object->lock, flags);
1500 }
1501 rcu_read_unlock();
1502
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001503 /*
1504 * Re-scan the gray list for modified unreferenced objects.
1505 */
1506 scan_gray_list();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001507
1508 /*
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001509 * If scanning was stopped do not report any new unreferenced objects.
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001510 */
Catalin Marinas04609ccc2009-10-28 13:33:12 +00001511 if (scan_should_stop())
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001512 return;
1513
1514 /*
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001515 * Scanning result reporting.
1516 */
1517 rcu_read_lock();
1518 list_for_each_entry_rcu(object, &object_list, object_list) {
1519 spin_lock_irqsave(&object->lock, flags);
1520 if (unreferenced_object(object) &&
1521 !(object->flags & OBJECT_REPORTED)) {
1522 object->flags |= OBJECT_REPORTED;
1523 new_leaks++;
1524 }
1525 spin_unlock_irqrestore(&object->lock, flags);
1526 }
1527 rcu_read_unlock();
1528
Li Zefandc9b3f42014-04-03 14:46:26 -07001529 if (new_leaks) {
1530 kmemleak_found_leaks = true;
1531
Joe Perches756a025f02016-03-17 14:19:47 -07001532 pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
1533 new_leaks);
Li Zefandc9b3f42014-04-03 14:46:26 -07001534 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001535
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001536}
1537
1538/*
1539 * Thread function performing automatic memory scanning. Unreferenced objects
1540 * at the end of a memory scan are reported but only the first time.
1541 */
1542static int kmemleak_scan_thread(void *arg)
1543{
1544 static int first_run = 1;
1545
Joe Perchesae281062009-06-23 14:40:26 +01001546 pr_info("Automatic memory scanning thread started\n");
Catalin Marinasbf2a76b2009-07-07 10:32:55 +01001547 set_user_nice(current, 10);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001548
1549 /*
1550 * Wait before the first scan to allow the system to fully initialize.
1551 */
1552 if (first_run) {
Vegard Nossum98c42d92016-07-28 15:48:32 -07001553 signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001554 first_run = 0;
Vegard Nossum98c42d92016-07-28 15:48:32 -07001555 while (timeout && !kthread_should_stop())
1556 timeout = schedule_timeout_interruptible(timeout);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001557 }
1558
1559 while (!kthread_should_stop()) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001560 signed long timeout = jiffies_scan_wait;
1561
1562 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001563 kmemleak_scan();
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001564 mutex_unlock(&scan_mutex);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001565
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001566 /* wait before the next scan */
1567 while (timeout && !kthread_should_stop())
1568 timeout = schedule_timeout_interruptible(timeout);
1569 }
1570
Joe Perchesae281062009-06-23 14:40:26 +01001571 pr_info("Automatic memory scanning thread ended\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001572
1573 return 0;
1574}
1575
1576/*
1577 * Start the automatic memory scanning thread. This function must be called
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001578 * with the scan_mutex held.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001579 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001580static void start_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001581{
1582 if (scan_thread)
1583 return;
1584 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
1585 if (IS_ERR(scan_thread)) {
Joe Perches598d8092016-03-17 14:19:44 -07001586 pr_warn("Failed to create the scan thread\n");
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001587 scan_thread = NULL;
1588 }
1589}
1590
1591/*
Vinayak Menon1ce03c22018-03-29 10:14:09 +11001592 * Stop the automatic memory scanning thread.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001593 */
Luis R. Rodriguez7eb0d5e2009-09-08 17:31:45 +01001594static void stop_scan_thread(void)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001595{
1596 if (scan_thread) {
1597 kthread_stop(scan_thread);
1598 scan_thread = NULL;
1599 }
1600}
1601
1602/*
1603 * Iterate over the object_list and return the first valid object at or after
1604 * the required position with its use_count incremented. The function triggers
1605 * a memory scanning when the pos argument points to the first position.
1606 */
1607static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
1608{
1609 struct kmemleak_object *object;
1610 loff_t n = *pos;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001611 int err;
1612
1613 err = mutex_lock_interruptible(&scan_mutex);
1614 if (err < 0)
1615 return ERR_PTR(err);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001616
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001617 rcu_read_lock();
1618 list_for_each_entry_rcu(object, &object_list, object_list) {
1619 if (n-- > 0)
1620 continue;
1621 if (get_object(object))
1622 goto out;
1623 }
1624 object = NULL;
1625out:
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001626 return object;
1627}
1628
1629/*
1630 * Return the next object in the object_list. The function decrements the
1631 * use_count of the previous object and increases that of the next one.
1632 */
1633static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1634{
1635 struct kmemleak_object *prev_obj = v;
1636 struct kmemleak_object *next_obj = NULL;
Michael Wang58fac092012-08-17 12:33:34 +08001637 struct kmemleak_object *obj = prev_obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001638
1639 ++(*pos);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001640
Michael Wang58fac092012-08-17 12:33:34 +08001641 list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001642 if (get_object(obj)) {
1643 next_obj = obj;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001644 break;
Catalin Marinas52c3ce42011-04-27 16:44:26 +01001645 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001646 }
Catalin Marinas288c8572009-07-07 10:32:57 +01001647
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001648 put_object(prev_obj);
1649 return next_obj;
1650}
1651
1652/*
1653 * Decrement the use_count of the last object required, if any.
1654 */
1655static void kmemleak_seq_stop(struct seq_file *seq, void *v)
1656{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001657 if (!IS_ERR(v)) {
1658 /*
1659 * kmemleak_seq_start may return ERR_PTR if the scan_mutex
1660 * waiting was interrupted, so only release it if !IS_ERR.
1661 */
Catalin Marinasf5886c72009-07-29 16:26:57 +01001662 rcu_read_unlock();
Catalin Marinasb87324d2009-07-07 10:32:58 +01001663 mutex_unlock(&scan_mutex);
1664 if (v)
1665 put_object(v);
1666 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001667}
1668
1669/*
1670 * Print the information for an unreferenced object to the seq file.
1671 */
1672static int kmemleak_seq_show(struct seq_file *seq, void *v)
1673{
1674 struct kmemleak_object *object = v;
1675 unsigned long flags;
1676
1677 spin_lock_irqsave(&object->lock, flags);
Catalin Marinas288c8572009-07-07 10:32:57 +01001678 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
Catalin Marinas17bb9e02009-06-29 17:13:56 +01001679 print_unreferenced(seq, object);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001680 spin_unlock_irqrestore(&object->lock, flags);
1681 return 0;
1682}
1683
1684static const struct seq_operations kmemleak_seq_ops = {
1685 .start = kmemleak_seq_start,
1686 .next = kmemleak_seq_next,
1687 .stop = kmemleak_seq_stop,
1688 .show = kmemleak_seq_show,
1689};
1690
1691static int kmemleak_open(struct inode *inode, struct file *file)
1692{
Catalin Marinasb87324d2009-07-07 10:32:58 +01001693 return seq_open(file, &kmemleak_seq_ops);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001694}
1695
Catalin Marinas189d84e2009-08-27 14:29:15 +01001696static int dump_str_object_info(const char *str)
1697{
1698 unsigned long flags;
1699 struct kmemleak_object *object;
1700 unsigned long addr;
1701
Abhijit Pawardc053732012-12-18 14:23:27 -08001702 if (kstrtoul(str, 0, &addr))
1703 return -EINVAL;
Catalin Marinas189d84e2009-08-27 14:29:15 +01001704 object = find_and_get_object(addr, 0);
1705 if (!object) {
1706 pr_info("Unknown object at 0x%08lx\n", addr);
1707 return -EINVAL;
1708 }
1709
1710 spin_lock_irqsave(&object->lock, flags);
1711 dump_object_info(object);
1712 spin_unlock_irqrestore(&object->lock, flags);
1713
1714 put_object(object);
1715 return 0;
1716}
1717
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001718/*
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001719 * We use grey instead of black to ensure we can do future scans on the same
1720 * objects. If we did not do future scans these black objects could
1721 * potentially contain references to newly allocated objects in the future and
1722 * we'd end up with false positives.
1723 */
1724static void kmemleak_clear(void)
1725{
1726 struct kmemleak_object *object;
1727 unsigned long flags;
1728
1729 rcu_read_lock();
1730 list_for_each_entry_rcu(object, &object_list, object_list) {
1731 spin_lock_irqsave(&object->lock, flags);
1732 if ((object->flags & OBJECT_REPORTED) &&
1733 unreferenced_object(object))
Luis R. Rodrigueza1084c82009-09-04 17:44:52 -07001734 __paint_it(object, KMEMLEAK_GREY);
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001735 spin_unlock_irqrestore(&object->lock, flags);
1736 }
1737 rcu_read_unlock();
Li Zefandc9b3f42014-04-03 14:46:26 -07001738
1739 kmemleak_found_leaks = false;
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001740}
1741
Li Zefanc89da702014-04-03 14:46:27 -07001742static void __kmemleak_do_cleanup(void);
1743
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001744/*
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001745 * File write operation to configure kmemleak at run-time. The following
1746 * commands can be written to the /sys/kernel/debug/kmemleak file:
1747 * off - disable kmemleak (irreversible)
1748 * stack=on - enable the task stacks scanning
1749 * stack=off - disable the tasks stacks scanning
1750 * scan=on - start the automatic memory scanning thread
1751 * scan=off - stop the automatic memory scanning thread
1752 * scan=... - set the automatic memory scanning period in seconds (0 to
1753 * disable it)
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001754 * scan - trigger a memory scan
Luis R. Rodriguez30b37102009-09-04 17:44:51 -07001755 * clear - mark all current reported unreferenced kmemleak objects as
Li Zefanc89da702014-04-03 14:46:27 -07001756 * grey to ignore printing them, or free all kmemleak objects
1757 * if kmemleak has been disabled.
Catalin Marinas189d84e2009-08-27 14:29:15 +01001758 * dump=... - dump information about the object found at the given address
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001759 */
1760static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
1761 size_t size, loff_t *ppos)
1762{
1763 char buf[64];
1764 int buf_size;
Catalin Marinasb87324d2009-07-07 10:32:58 +01001765 int ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001766
1767 buf_size = min(size, (sizeof(buf) - 1));
1768 if (strncpy_from_user(buf, user_buf, buf_size) < 0)
1769 return -EFAULT;
1770 buf[buf_size] = 0;
1771
Catalin Marinasb87324d2009-07-07 10:32:58 +01001772 ret = mutex_lock_interruptible(&scan_mutex);
1773 if (ret < 0)
1774 return ret;
1775
Li Zefanc89da702014-04-03 14:46:27 -07001776 if (strncmp(buf, "clear", 5) == 0) {
Li Zefan8910ae82014-04-03 14:46:29 -07001777 if (kmemleak_enabled)
Li Zefanc89da702014-04-03 14:46:27 -07001778 kmemleak_clear();
1779 else
1780 __kmemleak_do_cleanup();
1781 goto out;
1782 }
1783
Li Zefan8910ae82014-04-03 14:46:29 -07001784 if (!kmemleak_enabled) {
Li Zefanc89da702014-04-03 14:46:27 -07001785 ret = -EBUSY;
1786 goto out;
1787 }
1788
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001789 if (strncmp(buf, "off", 3) == 0)
1790 kmemleak_disable();
1791 else if (strncmp(buf, "stack=on", 8) == 0)
1792 kmemleak_stack_scan = 1;
1793 else if (strncmp(buf, "stack=off", 9) == 0)
1794 kmemleak_stack_scan = 0;
1795 else if (strncmp(buf, "scan=on", 7) == 0)
1796 start_scan_thread();
1797 else if (strncmp(buf, "scan=off", 8) == 0)
1798 stop_scan_thread();
1799 else if (strncmp(buf, "scan=", 5) == 0) {
1800 unsigned long secs;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001801
Jingoo Han3dbb95f2013-09-11 14:20:25 -07001802 ret = kstrtoul(buf + 5, 0, &secs);
Catalin Marinasb87324d2009-07-07 10:32:58 +01001803 if (ret < 0)
1804 goto out;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001805 stop_scan_thread();
1806 if (secs) {
1807 jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
1808 start_scan_thread();
1809 }
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001810 } else if (strncmp(buf, "scan", 4) == 0)
1811 kmemleak_scan();
Catalin Marinas189d84e2009-08-27 14:29:15 +01001812 else if (strncmp(buf, "dump=", 5) == 0)
1813 ret = dump_str_object_info(buf + 5);
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001814 else
Catalin Marinasb87324d2009-07-07 10:32:58 +01001815 ret = -EINVAL;
1816
1817out:
1818 mutex_unlock(&scan_mutex);
1819 if (ret < 0)
1820 return ret;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001821
1822 /* ignore the rest of the buffer, only one command at a time */
1823 *ppos += size;
1824 return size;
1825}
1826
1827static const struct file_operations kmemleak_fops = {
1828 .owner = THIS_MODULE,
1829 .open = kmemleak_open,
1830 .read = seq_read,
1831 .write = kmemleak_write,
1832 .llseek = seq_lseek,
Li Zefan5f3bf192014-04-03 14:46:28 -07001833 .release = seq_release,
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001834};
1835
Li Zefanc89da702014-04-03 14:46:27 -07001836static void __kmemleak_do_cleanup(void)
1837{
1838 struct kmemleak_object *object;
1839
1840 rcu_read_lock();
1841 list_for_each_entry_rcu(object, &object_list, object_list)
1842 delete_object_full(object->pointer);
1843 rcu_read_unlock();
1844}
1845
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001846/*
Catalin Marinas74341702011-09-29 11:50:07 +01001847 * Stop the memory scanning thread and free the kmemleak internal objects if
1848 * no previous scan thread (otherwise, kmemleak may still have some useful
1849 * information on memory leaks).
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001850 */
Catalin Marinas179a8102009-09-07 10:14:42 +01001851static void kmemleak_do_cleanup(struct work_struct *work)
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001852{
Catalin Marinas4698c1f2009-06-26 17:38:27 +01001853 stop_scan_thread();
1854
Vinayak Menon1ce03c22018-03-29 10:14:09 +11001855 mutex_lock(&scan_mutex);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001856 /*
Vinayak Menon1ce03c22018-03-29 10:14:09 +11001857 * Once it is made sure that kmemleak_scan has stopped, it is safe to no
1858 * longer track object freeing. Ordering of the scan thread stopping and
1859 * the memory accesses below is guaranteed by the kthread_stop()
1860 * function.
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001861 */
1862 kmemleak_free_enabled = 0;
Vinayak Menon1ce03c22018-03-29 10:14:09 +11001863 mutex_unlock(&scan_mutex);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001864
Li Zefanc89da702014-04-03 14:46:27 -07001865 if (!kmemleak_found_leaks)
1866 __kmemleak_do_cleanup();
1867 else
Joe Perches756a025f02016-03-17 14:19:47 -07001868 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 +01001869}
1870
Catalin Marinas179a8102009-09-07 10:14:42 +01001871static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001872
1873/*
1874 * Disable kmemleak. No memory allocation/freeing will be traced once this
1875 * function is called. Disabling kmemleak is an irreversible operation.
1876 */
1877static void kmemleak_disable(void)
1878{
1879 /* atomically check whether it was already invoked */
Li Zefan8910ae82014-04-03 14:46:29 -07001880 if (cmpxchg(&kmemleak_error, 0, 1))
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001881 return;
1882
1883 /* stop any memory operation tracing */
Li Zefan8910ae82014-04-03 14:46:29 -07001884 kmemleak_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001885
1886 /* check whether it is too early for a kernel thread */
Li Zefan8910ae82014-04-03 14:46:29 -07001887 if (kmemleak_initialized)
Catalin Marinas179a8102009-09-07 10:14:42 +01001888 schedule_work(&cleanup_work);
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001889 else
1890 kmemleak_free_enabled = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001891
1892 pr_info("Kernel memory leak detector disabled\n");
1893}
1894
1895/*
1896 * Allow boot-time kmemleak disabling (enabled by default).
1897 */
1898static int kmemleak_boot_config(char *str)
1899{
1900 if (!str)
1901 return -EINVAL;
1902 if (strcmp(str, "off") == 0)
1903 kmemleak_disable();
Jason Baronab0155a2010-07-19 11:54:17 +01001904 else if (strcmp(str, "on") == 0)
1905 kmemleak_skip_disable = 1;
1906 else
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001907 return -EINVAL;
1908 return 0;
1909}
1910early_param("kmemleak", kmemleak_boot_config);
1911
Catalin Marinas5f790202011-09-28 12:17:03 +01001912static void __init print_log_trace(struct early_log *log)
1913{
1914 struct stack_trace trace;
1915
1916 trace.nr_entries = log->trace_len;
1917 trace.entries = log->trace;
1918
1919 pr_notice("Early log backtrace:\n");
1920 print_stack_trace(&trace, 2);
1921}
1922
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001923/*
Catalin Marinas20301172009-06-17 18:29:04 +01001924 * Kmemleak initialization.
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001925 */
1926void __init kmemleak_init(void)
1927{
1928 int i;
1929 unsigned long flags;
1930
Jason Baronab0155a2010-07-19 11:54:17 +01001931#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
1932 if (!kmemleak_skip_disable) {
Catalin Marinas3551a922014-05-09 15:36:59 -07001933 kmemleak_early_log = 0;
Jason Baronab0155a2010-07-19 11:54:17 +01001934 kmemleak_disable();
1935 return;
1936 }
1937#endif
1938
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001939 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
1940 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
1941
1942 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
1943 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001944
Wang Kai21cd3a62015-09-08 15:03:41 -07001945 if (crt_early_log > ARRAY_SIZE(early_log))
Joe Perches598d8092016-03-17 14:19:44 -07001946 pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
1947 crt_early_log);
Catalin Marinasb6693002011-09-28 17:22:56 +01001948
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001949 /* the kernel is still in UP mode, so disabling the IRQs is enough */
1950 local_irq_save(flags);
Catalin Marinas3551a922014-05-09 15:36:59 -07001951 kmemleak_early_log = 0;
Li Zefan8910ae82014-04-03 14:46:29 -07001952 if (kmemleak_error) {
Catalin Marinasb6693002011-09-28 17:22:56 +01001953 local_irq_restore(flags);
1954 return;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001955 } else {
Li Zefan8910ae82014-04-03 14:46:29 -07001956 kmemleak_enabled = 1;
Catalin Marinasc5f3b1a2015-06-24 16:58:26 -07001957 kmemleak_free_enabled = 1;
1958 }
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001959 local_irq_restore(flags);
1960
1961 /*
1962 * This is the point where tracking allocations is safe. Automatic
1963 * scanning is started during the late initcall. Add the early logged
1964 * callbacks to the kmemleak infrastructure.
1965 */
1966 for (i = 0; i < crt_early_log; i++) {
1967 struct early_log *log = &early_log[i];
1968
1969 switch (log->op_type) {
1970 case KMEMLEAK_ALLOC:
Catalin Marinasfd678962009-08-27 14:29:17 +01001971 early_alloc(log);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001972 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001973 case KMEMLEAK_ALLOC_PERCPU:
1974 early_alloc_percpu(log);
1975 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001976 case KMEMLEAK_FREE:
1977 kmemleak_free(log->ptr);
1978 break;
Catalin Marinas53238a62009-07-07 10:33:00 +01001979 case KMEMLEAK_FREE_PART:
1980 kmemleak_free_part(log->ptr, log->size);
1981 break;
Catalin Marinasf528f0b2011-09-26 17:12:53 +01001982 case KMEMLEAK_FREE_PERCPU:
1983 kmemleak_free_percpu(log->ptr);
1984 break;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001985 case KMEMLEAK_NOT_LEAK:
1986 kmemleak_not_leak(log->ptr);
1987 break;
1988 case KMEMLEAK_IGNORE:
1989 kmemleak_ignore(log->ptr);
1990 break;
1991 case KMEMLEAK_SCAN_AREA:
Catalin Marinasc017b4b2009-10-28 13:33:09 +00001992 kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01001993 break;
1994 case KMEMLEAK_NO_SCAN:
1995 kmemleak_no_scan(log->ptr);
1996 break;
1997 default:
Catalin Marinas5f790202011-09-28 12:17:03 +01001998 kmemleak_warn("Unknown early log operation: %d\n",
1999 log->op_type);
2000 }
2001
Li Zefan8910ae82014-04-03 14:46:29 -07002002 if (kmemleak_warning) {
Catalin Marinas5f790202011-09-28 12:17:03 +01002003 print_log_trace(log);
Li Zefan8910ae82014-04-03 14:46:29 -07002004 kmemleak_warning = 0;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002005 }
2006 }
2007}
2008
2009/*
2010 * Late initialization function.
2011 */
2012static int __init kmemleak_late_init(void)
2013{
2014 struct dentry *dentry;
2015
Li Zefan8910ae82014-04-03 14:46:29 -07002016 kmemleak_initialized = 1;
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002017
Li Zefan8910ae82014-04-03 14:46:29 -07002018 if (kmemleak_error) {
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002019 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002020 * Some error occurred and kmemleak was disabled. There is a
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002021 * small chance that kmemleak_disable() was called immediately
2022 * after setting kmemleak_initialized and we may end up with
2023 * two clean-up threads but serialized by scan_mutex.
2024 */
Catalin Marinas179a8102009-09-07 10:14:42 +01002025 schedule_work(&cleanup_work);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002026 return -ENOMEM;
2027 }
2028
2029 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL,
2030 &kmemleak_fops);
2031 if (!dentry)
Joe Perches598d8092016-03-17 14:19:44 -07002032 pr_warn("Failed to create the debugfs kmemleak file\n");
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002033 mutex_lock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002034 start_scan_thread();
Catalin Marinas4698c1f2009-06-26 17:38:27 +01002035 mutex_unlock(&scan_mutex);
Catalin Marinas3c7b4e62009-06-11 13:22:39 +01002036
2037 pr_info("Kernel memory leak detector initialized\n");
2038
2039 return 0;
2040}
2041late_initcall(kmemleak_late_init);