Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1 | /* |
| 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 |
| 32 | * blocks. The object_tree_root is a priority search tree used to look-up |
| 33 | * 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 Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 51 | * 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 Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 55 | * |
| 56 | * The kmemleak_object structures have a use_count incremented or decremented |
| 57 | * using the get_object()/put_object() functions. When the use_count becomes |
| 58 | * 0, this count can no longer be incremented and put_object() schedules the |
| 59 | * kmemleak_object freeing via an RCU callback. All calls to the get_object() |
| 60 | * function must be protected by rcu_read_lock() to avoid accessing a freed |
| 61 | * structure. |
| 62 | */ |
| 63 | |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 64 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 65 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 66 | #include <linux/init.h> |
| 67 | #include <linux/kernel.h> |
| 68 | #include <linux/list.h> |
| 69 | #include <linux/sched.h> |
| 70 | #include <linux/jiffies.h> |
| 71 | #include <linux/delay.h> |
| 72 | #include <linux/module.h> |
| 73 | #include <linux/kthread.h> |
| 74 | #include <linux/prio_tree.h> |
| 75 | #include <linux/gfp.h> |
| 76 | #include <linux/fs.h> |
| 77 | #include <linux/debugfs.h> |
| 78 | #include <linux/seq_file.h> |
| 79 | #include <linux/cpumask.h> |
| 80 | #include <linux/spinlock.h> |
| 81 | #include <linux/mutex.h> |
| 82 | #include <linux/rcupdate.h> |
| 83 | #include <linux/stacktrace.h> |
| 84 | #include <linux/cache.h> |
| 85 | #include <linux/percpu.h> |
| 86 | #include <linux/hardirq.h> |
| 87 | #include <linux/mmzone.h> |
| 88 | #include <linux/slab.h> |
| 89 | #include <linux/thread_info.h> |
| 90 | #include <linux/err.h> |
| 91 | #include <linux/uaccess.h> |
| 92 | #include <linux/string.h> |
| 93 | #include <linux/nodemask.h> |
| 94 | #include <linux/mm.h> |
| 95 | |
| 96 | #include <asm/sections.h> |
| 97 | #include <asm/processor.h> |
| 98 | #include <asm/atomic.h> |
| 99 | |
| 100 | #include <linux/kmemleak.h> |
| 101 | |
| 102 | /* |
| 103 | * Kmemleak configuration and common defines. |
| 104 | */ |
| 105 | #define MAX_TRACE 16 /* stack trace length */ |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 106 | #define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 107 | #define SECS_FIRST_SCAN 60 /* delay before the first scan */ |
| 108 | #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 109 | #define GRAY_LIST_PASSES 25 /* maximum number of gray list scans */ |
Catalin Marinas | af98603 | 2009-08-27 14:29:12 +0100 | [diff] [blame] | 110 | #define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 111 | |
| 112 | #define BYTES_PER_POINTER sizeof(void *) |
| 113 | |
Catalin Marinas | 216c04b | 2009-06-17 18:29:02 +0100 | [diff] [blame] | 114 | /* GFP bitmask for kmemleak internal allocations */ |
| 115 | #define GFP_KMEMLEAK_MASK (GFP_KERNEL | GFP_ATOMIC) |
| 116 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 117 | /* scanning area inside a memory block */ |
| 118 | struct kmemleak_scan_area { |
| 119 | struct hlist_node node; |
| 120 | unsigned long offset; |
| 121 | size_t length; |
| 122 | }; |
| 123 | |
| 124 | /* |
| 125 | * Structure holding the metadata for each allocated memory block. |
| 126 | * Modifications to such objects should be made while holding the |
| 127 | * object->lock. Insertions or deletions from object_list, gray_list or |
| 128 | * tree_node are already protected by the corresponding locks or mutex (see |
| 129 | * the notes on locking above). These objects are reference-counted |
| 130 | * (use_count) and freed using the RCU mechanism. |
| 131 | */ |
| 132 | struct kmemleak_object { |
| 133 | spinlock_t lock; |
| 134 | unsigned long flags; /* object status flags */ |
| 135 | struct list_head object_list; |
| 136 | struct list_head gray_list; |
| 137 | struct prio_tree_node tree_node; |
| 138 | struct rcu_head rcu; /* object_list lockless traversal */ |
| 139 | /* object usage count; object freed when use_count == 0 */ |
| 140 | atomic_t use_count; |
| 141 | unsigned long pointer; |
| 142 | size_t size; |
| 143 | /* minimum number of a pointers found before it is considered leak */ |
| 144 | int min_count; |
| 145 | /* the total number of pointers found pointing to this object */ |
| 146 | int count; |
| 147 | /* memory ranges to be scanned inside an object (empty for all) */ |
| 148 | struct hlist_head area_list; |
| 149 | unsigned long trace[MAX_TRACE]; |
| 150 | unsigned int trace_len; |
| 151 | unsigned long jiffies; /* creation timestamp */ |
| 152 | pid_t pid; /* pid of the current task */ |
| 153 | char comm[TASK_COMM_LEN]; /* executable name */ |
| 154 | }; |
| 155 | |
| 156 | /* flag representing the memory block allocation status */ |
| 157 | #define OBJECT_ALLOCATED (1 << 0) |
| 158 | /* flag set after the first reporting of an unreference object */ |
| 159 | #define OBJECT_REPORTED (1 << 1) |
| 160 | /* flag set to not scan the object */ |
| 161 | #define OBJECT_NO_SCAN (1 << 2) |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 162 | /* flag set on newly allocated objects */ |
| 163 | #define OBJECT_NEW (1 << 3) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 164 | |
| 165 | /* the list of all allocated objects */ |
| 166 | static LIST_HEAD(object_list); |
| 167 | /* the list of gray-colored objects (see color_gray comment below) */ |
| 168 | static LIST_HEAD(gray_list); |
| 169 | /* prio search tree for object boundaries */ |
| 170 | static struct prio_tree_root object_tree_root; |
| 171 | /* rw_lock protecting the access to object_list and prio_tree_root */ |
| 172 | static DEFINE_RWLOCK(kmemleak_lock); |
| 173 | |
| 174 | /* allocation caches for kmemleak internal data */ |
| 175 | static struct kmem_cache *object_cache; |
| 176 | static struct kmem_cache *scan_area_cache; |
| 177 | |
| 178 | /* set if tracing memory operations is enabled */ |
| 179 | static atomic_t kmemleak_enabled = ATOMIC_INIT(0); |
| 180 | /* set in the late_initcall if there were no errors */ |
| 181 | static atomic_t kmemleak_initialized = ATOMIC_INIT(0); |
| 182 | /* enables or disables early logging of the memory operations */ |
| 183 | static atomic_t kmemleak_early_log = ATOMIC_INIT(1); |
| 184 | /* set if a fata kmemleak error has occurred */ |
| 185 | static atomic_t kmemleak_error = ATOMIC_INIT(0); |
| 186 | |
| 187 | /* minimum and maximum address that may be valid pointers */ |
| 188 | static unsigned long min_addr = ULONG_MAX; |
| 189 | static unsigned long max_addr; |
| 190 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 191 | static struct task_struct *scan_thread; |
Catalin Marinas | acf4968 | 2009-06-26 17:38:29 +0100 | [diff] [blame] | 192 | /* used to avoid reporting of recently allocated objects */ |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 193 | static unsigned long jiffies_min_age; |
Catalin Marinas | acf4968 | 2009-06-26 17:38:29 +0100 | [diff] [blame] | 194 | static unsigned long jiffies_last_scan; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 195 | /* delay between automatic memory scannings */ |
| 196 | static signed long jiffies_scan_wait; |
| 197 | /* enables or disables the task stacks scanning */ |
Catalin Marinas | e0a2a16 | 2009-06-26 17:38:25 +0100 | [diff] [blame] | 198 | static int kmemleak_stack_scan = 1; |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 199 | /* protects the memory scanning, parameters and debug/kmemleak file access */ |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 200 | static DEFINE_MUTEX(scan_mutex); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 201 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 202 | /* |
Catalin Marinas | 2030117 | 2009-06-17 18:29:04 +0100 | [diff] [blame] | 203 | * Early object allocation/freeing logging. Kmemleak is initialized after the |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 204 | * kernel allocator. However, both the kernel allocator and kmemleak may |
Catalin Marinas | 2030117 | 2009-06-17 18:29:04 +0100 | [diff] [blame] | 205 | * allocate memory blocks which need to be tracked. Kmemleak defines an |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 206 | * arbitrary buffer to hold the allocation/freeing information before it is |
| 207 | * fully initialized. |
| 208 | */ |
| 209 | |
| 210 | /* kmemleak operation type for early logging */ |
| 211 | enum { |
| 212 | KMEMLEAK_ALLOC, |
| 213 | KMEMLEAK_FREE, |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 214 | KMEMLEAK_FREE_PART, |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 215 | KMEMLEAK_NOT_LEAK, |
| 216 | KMEMLEAK_IGNORE, |
| 217 | KMEMLEAK_SCAN_AREA, |
| 218 | KMEMLEAK_NO_SCAN |
| 219 | }; |
| 220 | |
| 221 | /* |
| 222 | * Structure holding the information passed to kmemleak callbacks during the |
| 223 | * early logging. |
| 224 | */ |
| 225 | struct early_log { |
| 226 | int op_type; /* kmemleak operation type */ |
| 227 | const void *ptr; /* allocated/freed memory block */ |
| 228 | size_t size; /* memory block size */ |
| 229 | int min_count; /* minimum reference count */ |
| 230 | unsigned long offset; /* scan area offset */ |
| 231 | size_t length; /* scan area length */ |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 232 | unsigned long trace[MAX_TRACE]; /* stack trace */ |
| 233 | unsigned int trace_len; /* stack trace length */ |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 234 | }; |
| 235 | |
| 236 | /* early logging buffer and current position */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 237 | static struct early_log |
| 238 | early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata; |
| 239 | static int crt_early_log __initdata; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 240 | |
| 241 | static void kmemleak_disable(void); |
| 242 | |
| 243 | /* |
| 244 | * Print a warning and dump the stack trace. |
| 245 | */ |
| 246 | #define kmemleak_warn(x...) do { \ |
| 247 | pr_warning(x); \ |
| 248 | dump_stack(); \ |
| 249 | } while (0) |
| 250 | |
| 251 | /* |
| 252 | * Macro invoked when a serious kmemleak condition occured and cannot be |
Catalin Marinas | 2030117 | 2009-06-17 18:29:04 +0100 | [diff] [blame] | 253 | * recovered from. Kmemleak will be disabled and further allocation/freeing |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 254 | * tracing no longer available. |
| 255 | */ |
Catalin Marinas | 000814f | 2009-06-17 18:29:03 +0100 | [diff] [blame] | 256 | #define kmemleak_stop(x...) do { \ |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 257 | kmemleak_warn(x); \ |
| 258 | kmemleak_disable(); \ |
| 259 | } while (0) |
| 260 | |
| 261 | /* |
| 262 | * Object colors, encoded with count and min_count: |
| 263 | * - white - orphan object, not enough references to it (count < min_count) |
| 264 | * - gray - not orphan, not marked as false positive (min_count == 0) or |
| 265 | * sufficient references to it (count >= min_count) |
| 266 | * - black - ignore, it doesn't contain references (e.g. text section) |
| 267 | * (min_count == -1). No function defined for this color. |
| 268 | * Newly created objects don't have any color assigned (object->count == -1) |
| 269 | * before the next memory scan when they become white. |
| 270 | */ |
| 271 | static int color_white(const struct kmemleak_object *object) |
| 272 | { |
| 273 | return object->count != -1 && object->count < object->min_count; |
| 274 | } |
| 275 | |
| 276 | static int color_gray(const struct kmemleak_object *object) |
| 277 | { |
| 278 | return object->min_count != -1 && object->count >= object->min_count; |
| 279 | } |
| 280 | |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 281 | static int color_black(const struct kmemleak_object *object) |
| 282 | { |
| 283 | return object->min_count == -1; |
| 284 | } |
| 285 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 286 | /* |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 287 | * Objects are considered unreferenced only if their color is white, they have |
| 288 | * not be deleted and have a minimum age to avoid false positives caused by |
| 289 | * pointers temporarily stored in CPU registers. |
| 290 | */ |
| 291 | static int unreferenced_object(struct kmemleak_object *object) |
| 292 | { |
| 293 | return (object->flags & OBJECT_ALLOCATED) && color_white(object) && |
Catalin Marinas | acf4968 | 2009-06-26 17:38:29 +0100 | [diff] [blame] | 294 | time_before_eq(object->jiffies + jiffies_min_age, |
| 295 | jiffies_last_scan); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 296 | } |
| 297 | |
| 298 | /* |
Catalin Marinas | bab4a34 | 2009-06-26 17:38:26 +0100 | [diff] [blame] | 299 | * Printing of the unreferenced objects information to the seq file. The |
| 300 | * print_unreferenced function must be called with the object->lock held. |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 301 | */ |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 302 | static void print_unreferenced(struct seq_file *seq, |
| 303 | struct kmemleak_object *object) |
| 304 | { |
| 305 | int i; |
| 306 | |
Catalin Marinas | bab4a34 | 2009-06-26 17:38:26 +0100 | [diff] [blame] | 307 | seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", |
| 308 | object->pointer, object->size); |
| 309 | seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", |
| 310 | object->comm, object->pid, object->jiffies); |
| 311 | seq_printf(seq, " backtrace:\n"); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 312 | |
| 313 | for (i = 0; i < object->trace_len; i++) { |
| 314 | void *ptr = (void *)object->trace[i]; |
Catalin Marinas | bab4a34 | 2009-06-26 17:38:26 +0100 | [diff] [blame] | 315 | seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 316 | } |
| 317 | } |
| 318 | |
| 319 | /* |
| 320 | * Print the kmemleak_object information. This function is used mainly for |
| 321 | * debugging special cases when kmemleak operations. It must be called with |
| 322 | * the object->lock held. |
| 323 | */ |
| 324 | static void dump_object_info(struct kmemleak_object *object) |
| 325 | { |
| 326 | struct stack_trace trace; |
| 327 | |
| 328 | trace.nr_entries = object->trace_len; |
| 329 | trace.entries = object->trace; |
| 330 | |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 331 | pr_notice("Object 0x%08lx (size %zu):\n", |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 332 | object->tree_node.start, object->size); |
| 333 | pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", |
| 334 | object->comm, object->pid, object->jiffies); |
| 335 | pr_notice(" min_count = %d\n", object->min_count); |
| 336 | pr_notice(" count = %d\n", object->count); |
Catalin Marinas | 189d84e | 2009-08-27 14:29:15 +0100 | [diff] [blame] | 337 | pr_notice(" flags = 0x%lx\n", object->flags); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 338 | pr_notice(" backtrace:\n"); |
| 339 | print_stack_trace(&trace, 4); |
| 340 | } |
| 341 | |
| 342 | /* |
| 343 | * Look-up a memory block metadata (kmemleak_object) in the priority search |
| 344 | * tree based on a pointer value. If alias is 0, only values pointing to the |
| 345 | * beginning of the memory block are allowed. The kmemleak_lock must be held |
| 346 | * when calling this function. |
| 347 | */ |
| 348 | static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) |
| 349 | { |
| 350 | struct prio_tree_node *node; |
| 351 | struct prio_tree_iter iter; |
| 352 | struct kmemleak_object *object; |
| 353 | |
| 354 | prio_tree_iter_init(&iter, &object_tree_root, ptr, ptr); |
| 355 | node = prio_tree_next(&iter); |
| 356 | if (node) { |
| 357 | object = prio_tree_entry(node, struct kmemleak_object, |
| 358 | tree_node); |
| 359 | if (!alias && object->pointer != ptr) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 360 | kmemleak_warn("Found object by alias"); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 361 | object = NULL; |
| 362 | } |
| 363 | } else |
| 364 | object = NULL; |
| 365 | |
| 366 | return object; |
| 367 | } |
| 368 | |
| 369 | /* |
| 370 | * Increment the object use_count. Return 1 if successful or 0 otherwise. Note |
| 371 | * that once an object's use_count reached 0, the RCU freeing was already |
| 372 | * registered and the object should no longer be used. This function must be |
| 373 | * called under the protection of rcu_read_lock(). |
| 374 | */ |
| 375 | static int get_object(struct kmemleak_object *object) |
| 376 | { |
| 377 | return atomic_inc_not_zero(&object->use_count); |
| 378 | } |
| 379 | |
| 380 | /* |
| 381 | * RCU callback to free a kmemleak_object. |
| 382 | */ |
| 383 | static void free_object_rcu(struct rcu_head *rcu) |
| 384 | { |
| 385 | struct hlist_node *elem, *tmp; |
| 386 | struct kmemleak_scan_area *area; |
| 387 | struct kmemleak_object *object = |
| 388 | container_of(rcu, struct kmemleak_object, rcu); |
| 389 | |
| 390 | /* |
| 391 | * Once use_count is 0 (guaranteed by put_object), there is no other |
| 392 | * code accessing this object, hence no need for locking. |
| 393 | */ |
| 394 | hlist_for_each_entry_safe(area, elem, tmp, &object->area_list, node) { |
| 395 | hlist_del(elem); |
| 396 | kmem_cache_free(scan_area_cache, area); |
| 397 | } |
| 398 | kmem_cache_free(object_cache, object); |
| 399 | } |
| 400 | |
| 401 | /* |
| 402 | * Decrement the object use_count. Once the count is 0, free the object using |
| 403 | * an RCU callback. Since put_object() may be called via the kmemleak_free() -> |
| 404 | * delete_object() path, the delayed RCU freeing ensures that there is no |
| 405 | * recursive call to the kernel allocator. Lock-less RCU object_list traversal |
| 406 | * is also possible. |
| 407 | */ |
| 408 | static void put_object(struct kmemleak_object *object) |
| 409 | { |
| 410 | if (!atomic_dec_and_test(&object->use_count)) |
| 411 | return; |
| 412 | |
| 413 | /* should only get here after delete_object was called */ |
| 414 | WARN_ON(object->flags & OBJECT_ALLOCATED); |
| 415 | |
| 416 | call_rcu(&object->rcu, free_object_rcu); |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * Look up an object in the prio search tree and increase its use_count. |
| 421 | */ |
| 422 | static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) |
| 423 | { |
| 424 | unsigned long flags; |
| 425 | struct kmemleak_object *object = NULL; |
| 426 | |
| 427 | rcu_read_lock(); |
| 428 | read_lock_irqsave(&kmemleak_lock, flags); |
| 429 | if (ptr >= min_addr && ptr < max_addr) |
| 430 | object = lookup_object(ptr, alias); |
| 431 | read_unlock_irqrestore(&kmemleak_lock, flags); |
| 432 | |
| 433 | /* check whether the object is still available */ |
| 434 | if (object && !get_object(object)) |
| 435 | object = NULL; |
| 436 | rcu_read_unlock(); |
| 437 | |
| 438 | return object; |
| 439 | } |
| 440 | |
| 441 | /* |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 442 | * Save stack trace to the given array of MAX_TRACE size. |
| 443 | */ |
| 444 | static int __save_stack_trace(unsigned long *trace) |
| 445 | { |
| 446 | struct stack_trace stack_trace; |
| 447 | |
| 448 | stack_trace.max_entries = MAX_TRACE; |
| 449 | stack_trace.nr_entries = 0; |
| 450 | stack_trace.entries = trace; |
| 451 | stack_trace.skip = 2; |
| 452 | save_stack_trace(&stack_trace); |
| 453 | |
| 454 | return stack_trace.nr_entries; |
| 455 | } |
| 456 | |
| 457 | /* |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 458 | * Create the metadata (struct kmemleak_object) corresponding to an allocated |
| 459 | * memory block and add it to the object_list and object_tree_root. |
| 460 | */ |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 461 | static struct kmemleak_object *create_object(unsigned long ptr, size_t size, |
| 462 | int min_count, gfp_t gfp) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 463 | { |
| 464 | unsigned long flags; |
| 465 | struct kmemleak_object *object; |
| 466 | struct prio_tree_node *node; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 467 | |
Catalin Marinas | 216c04b | 2009-06-17 18:29:02 +0100 | [diff] [blame] | 468 | object = kmem_cache_alloc(object_cache, gfp & GFP_KMEMLEAK_MASK); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 469 | if (!object) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 470 | kmemleak_stop("Cannot allocate a kmemleak_object structure\n"); |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 471 | return NULL; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 472 | } |
| 473 | |
| 474 | INIT_LIST_HEAD(&object->object_list); |
| 475 | INIT_LIST_HEAD(&object->gray_list); |
| 476 | INIT_HLIST_HEAD(&object->area_list); |
| 477 | spin_lock_init(&object->lock); |
| 478 | atomic_set(&object->use_count, 1); |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 479 | object->flags = OBJECT_ALLOCATED | OBJECT_NEW; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 480 | object->pointer = ptr; |
| 481 | object->size = size; |
| 482 | object->min_count = min_count; |
| 483 | object->count = -1; /* no color initially */ |
| 484 | object->jiffies = jiffies; |
| 485 | |
| 486 | /* task information */ |
| 487 | if (in_irq()) { |
| 488 | object->pid = 0; |
| 489 | strncpy(object->comm, "hardirq", sizeof(object->comm)); |
| 490 | } else if (in_softirq()) { |
| 491 | object->pid = 0; |
| 492 | strncpy(object->comm, "softirq", sizeof(object->comm)); |
| 493 | } else { |
| 494 | object->pid = current->pid; |
| 495 | /* |
| 496 | * There is a small chance of a race with set_task_comm(), |
| 497 | * however using get_task_comm() here may cause locking |
| 498 | * dependency issues with current->alloc_lock. In the worst |
| 499 | * case, the command line is not correct. |
| 500 | */ |
| 501 | strncpy(object->comm, current->comm, sizeof(object->comm)); |
| 502 | } |
| 503 | |
| 504 | /* kernel backtrace */ |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 505 | object->trace_len = __save_stack_trace(object->trace); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 506 | |
| 507 | INIT_PRIO_TREE_NODE(&object->tree_node); |
| 508 | object->tree_node.start = ptr; |
| 509 | object->tree_node.last = ptr + size - 1; |
| 510 | |
| 511 | write_lock_irqsave(&kmemleak_lock, flags); |
| 512 | min_addr = min(min_addr, ptr); |
| 513 | max_addr = max(max_addr, ptr + size); |
| 514 | node = prio_tree_insert(&object_tree_root, &object->tree_node); |
| 515 | /* |
| 516 | * The code calling the kernel does not yet have the pointer to the |
| 517 | * memory block to be able to free it. However, we still hold the |
| 518 | * kmemleak_lock here in case parts of the kernel started freeing |
| 519 | * random memory blocks. |
| 520 | */ |
| 521 | if (node != &object->tree_node) { |
| 522 | unsigned long flags; |
| 523 | |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 524 | kmemleak_stop("Cannot insert 0x%lx into the object search tree " |
| 525 | "(already existing)\n", ptr); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 526 | object = lookup_object(ptr, 1); |
| 527 | spin_lock_irqsave(&object->lock, flags); |
| 528 | dump_object_info(object); |
| 529 | spin_unlock_irqrestore(&object->lock, flags); |
| 530 | |
| 531 | goto out; |
| 532 | } |
| 533 | list_add_tail_rcu(&object->object_list, &object_list); |
| 534 | out: |
| 535 | write_unlock_irqrestore(&kmemleak_lock, flags); |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 536 | return object; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 537 | } |
| 538 | |
| 539 | /* |
| 540 | * Remove the metadata (struct kmemleak_object) for a memory block from the |
| 541 | * object_list and object_tree_root and decrement its use_count. |
| 542 | */ |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 543 | static void __delete_object(struct kmemleak_object *object) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 544 | { |
| 545 | unsigned long flags; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 546 | |
| 547 | write_lock_irqsave(&kmemleak_lock, flags); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 548 | prio_tree_remove(&object_tree_root, &object->tree_node); |
| 549 | list_del_rcu(&object->object_list); |
| 550 | write_unlock_irqrestore(&kmemleak_lock, flags); |
| 551 | |
| 552 | WARN_ON(!(object->flags & OBJECT_ALLOCATED)); |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 553 | WARN_ON(atomic_read(&object->use_count) < 2); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 554 | |
| 555 | /* |
| 556 | * Locking here also ensures that the corresponding memory block |
| 557 | * cannot be freed when it is being scanned. |
| 558 | */ |
| 559 | spin_lock_irqsave(&object->lock, flags); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 560 | object->flags &= ~OBJECT_ALLOCATED; |
| 561 | spin_unlock_irqrestore(&object->lock, flags); |
| 562 | put_object(object); |
| 563 | } |
| 564 | |
| 565 | /* |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 566 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and |
| 567 | * delete it. |
| 568 | */ |
| 569 | static void delete_object_full(unsigned long ptr) |
| 570 | { |
| 571 | struct kmemleak_object *object; |
| 572 | |
| 573 | object = find_and_get_object(ptr, 0); |
| 574 | if (!object) { |
| 575 | #ifdef DEBUG |
| 576 | kmemleak_warn("Freeing unknown object at 0x%08lx\n", |
| 577 | ptr); |
| 578 | #endif |
| 579 | return; |
| 580 | } |
| 581 | __delete_object(object); |
| 582 | put_object(object); |
| 583 | } |
| 584 | |
| 585 | /* |
| 586 | * Look up the metadata (struct kmemleak_object) corresponding to ptr and |
| 587 | * delete it. If the memory block is partially freed, the function may create |
| 588 | * additional metadata for the remaining parts of the block. |
| 589 | */ |
| 590 | static void delete_object_part(unsigned long ptr, size_t size) |
| 591 | { |
| 592 | struct kmemleak_object *object; |
| 593 | unsigned long start, end; |
| 594 | |
| 595 | object = find_and_get_object(ptr, 1); |
| 596 | if (!object) { |
| 597 | #ifdef DEBUG |
| 598 | kmemleak_warn("Partially freeing unknown object at 0x%08lx " |
| 599 | "(size %zu)\n", ptr, size); |
| 600 | #endif |
| 601 | return; |
| 602 | } |
| 603 | __delete_object(object); |
| 604 | |
| 605 | /* |
| 606 | * Create one or two objects that may result from the memory block |
| 607 | * split. Note that partial freeing is only done by free_bootmem() and |
| 608 | * this happens before kmemleak_init() is called. The path below is |
| 609 | * only executed during early log recording in kmemleak_init(), so |
| 610 | * GFP_KERNEL is enough. |
| 611 | */ |
| 612 | start = object->pointer; |
| 613 | end = object->pointer + object->size; |
| 614 | if (ptr > start) |
| 615 | create_object(start, ptr - start, object->min_count, |
| 616 | GFP_KERNEL); |
| 617 | if (ptr + size < end) |
| 618 | create_object(ptr + size, end - ptr - size, object->min_count, |
| 619 | GFP_KERNEL); |
| 620 | |
| 621 | put_object(object); |
| 622 | } |
| 623 | /* |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 624 | * Make a object permanently as gray-colored so that it can no longer be |
| 625 | * reported as a leak. This is used in general to mark a false positive. |
| 626 | */ |
| 627 | static void make_gray_object(unsigned long ptr) |
| 628 | { |
| 629 | unsigned long flags; |
| 630 | struct kmemleak_object *object; |
| 631 | |
| 632 | object = find_and_get_object(ptr, 0); |
| 633 | if (!object) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 634 | kmemleak_warn("Graying unknown object at 0x%08lx\n", ptr); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 635 | return; |
| 636 | } |
| 637 | |
| 638 | spin_lock_irqsave(&object->lock, flags); |
| 639 | object->min_count = 0; |
| 640 | spin_unlock_irqrestore(&object->lock, flags); |
| 641 | put_object(object); |
| 642 | } |
| 643 | |
| 644 | /* |
| 645 | * Mark the object as black-colored so that it is ignored from scans and |
| 646 | * reporting. |
| 647 | */ |
| 648 | static void make_black_object(unsigned long ptr) |
| 649 | { |
| 650 | unsigned long flags; |
| 651 | struct kmemleak_object *object; |
| 652 | |
| 653 | object = find_and_get_object(ptr, 0); |
| 654 | if (!object) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 655 | kmemleak_warn("Blacking unknown object at 0x%08lx\n", ptr); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 656 | return; |
| 657 | } |
| 658 | |
| 659 | spin_lock_irqsave(&object->lock, flags); |
| 660 | object->min_count = -1; |
Catalin Marinas | af98603 | 2009-08-27 14:29:12 +0100 | [diff] [blame] | 661 | object->flags |= OBJECT_NO_SCAN; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 662 | spin_unlock_irqrestore(&object->lock, flags); |
| 663 | put_object(object); |
| 664 | } |
| 665 | |
| 666 | /* |
| 667 | * Add a scanning area to the object. If at least one such area is added, |
| 668 | * kmemleak will only scan these ranges rather than the whole memory block. |
| 669 | */ |
| 670 | static void add_scan_area(unsigned long ptr, unsigned long offset, |
| 671 | size_t length, gfp_t gfp) |
| 672 | { |
| 673 | unsigned long flags; |
| 674 | struct kmemleak_object *object; |
| 675 | struct kmemleak_scan_area *area; |
| 676 | |
| 677 | object = find_and_get_object(ptr, 0); |
| 678 | if (!object) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 679 | kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", |
| 680 | ptr); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 681 | return; |
| 682 | } |
| 683 | |
Catalin Marinas | 216c04b | 2009-06-17 18:29:02 +0100 | [diff] [blame] | 684 | area = kmem_cache_alloc(scan_area_cache, gfp & GFP_KMEMLEAK_MASK); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 685 | if (!area) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 686 | kmemleak_warn("Cannot allocate a scan area\n"); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 687 | goto out; |
| 688 | } |
| 689 | |
| 690 | spin_lock_irqsave(&object->lock, flags); |
| 691 | if (offset + length > object->size) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 692 | kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 693 | dump_object_info(object); |
| 694 | kmem_cache_free(scan_area_cache, area); |
| 695 | goto out_unlock; |
| 696 | } |
| 697 | |
| 698 | INIT_HLIST_NODE(&area->node); |
| 699 | area->offset = offset; |
| 700 | area->length = length; |
| 701 | |
| 702 | hlist_add_head(&area->node, &object->area_list); |
| 703 | out_unlock: |
| 704 | spin_unlock_irqrestore(&object->lock, flags); |
| 705 | out: |
| 706 | put_object(object); |
| 707 | } |
| 708 | |
| 709 | /* |
| 710 | * Set the OBJECT_NO_SCAN flag for the object corresponding to the give |
| 711 | * pointer. Such object will not be scanned by kmemleak but references to it |
| 712 | * are searched. |
| 713 | */ |
| 714 | static void object_no_scan(unsigned long ptr) |
| 715 | { |
| 716 | unsigned long flags; |
| 717 | struct kmemleak_object *object; |
| 718 | |
| 719 | object = find_and_get_object(ptr, 0); |
| 720 | if (!object) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 721 | kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 722 | return; |
| 723 | } |
| 724 | |
| 725 | spin_lock_irqsave(&object->lock, flags); |
| 726 | object->flags |= OBJECT_NO_SCAN; |
| 727 | spin_unlock_irqrestore(&object->lock, flags); |
| 728 | put_object(object); |
| 729 | } |
| 730 | |
| 731 | /* |
| 732 | * Log an early kmemleak_* call to the early_log buffer. These calls will be |
| 733 | * processed later once kmemleak is fully initialized. |
| 734 | */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 735 | static void __init log_early(int op_type, const void *ptr, size_t size, |
| 736 | int min_count, unsigned long offset, size_t length) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 737 | { |
| 738 | unsigned long flags; |
| 739 | struct early_log *log; |
| 740 | |
| 741 | if (crt_early_log >= ARRAY_SIZE(early_log)) { |
Catalin Marinas | a9d9058 | 2009-06-25 10:16:11 +0100 | [diff] [blame] | 742 | pr_warning("Early log buffer exceeded\n"); |
| 743 | kmemleak_disable(); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 744 | return; |
| 745 | } |
| 746 | |
| 747 | /* |
| 748 | * There is no need for locking since the kernel is still in UP mode |
| 749 | * at this stage. Disabling the IRQs is enough. |
| 750 | */ |
| 751 | local_irq_save(flags); |
| 752 | log = &early_log[crt_early_log]; |
| 753 | log->op_type = op_type; |
| 754 | log->ptr = ptr; |
| 755 | log->size = size; |
| 756 | log->min_count = min_count; |
| 757 | log->offset = offset; |
| 758 | log->length = length; |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 759 | if (op_type == KMEMLEAK_ALLOC) |
| 760 | log->trace_len = __save_stack_trace(log->trace); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 761 | crt_early_log++; |
| 762 | local_irq_restore(flags); |
| 763 | } |
| 764 | |
| 765 | /* |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 766 | * Log an early allocated block and populate the stack trace. |
| 767 | */ |
| 768 | static void early_alloc(struct early_log *log) |
| 769 | { |
| 770 | struct kmemleak_object *object; |
| 771 | unsigned long flags; |
| 772 | int i; |
| 773 | |
| 774 | if (!atomic_read(&kmemleak_enabled) || !log->ptr || IS_ERR(log->ptr)) |
| 775 | return; |
| 776 | |
| 777 | /* |
| 778 | * RCU locking needed to ensure object is not freed via put_object(). |
| 779 | */ |
| 780 | rcu_read_lock(); |
| 781 | object = create_object((unsigned long)log->ptr, log->size, |
| 782 | log->min_count, GFP_KERNEL); |
| 783 | spin_lock_irqsave(&object->lock, flags); |
| 784 | for (i = 0; i < log->trace_len; i++) |
| 785 | object->trace[i] = log->trace[i]; |
| 786 | object->trace_len = log->trace_len; |
| 787 | spin_unlock_irqrestore(&object->lock, flags); |
| 788 | rcu_read_unlock(); |
| 789 | } |
| 790 | |
| 791 | /* |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 792 | * Memory allocation function callback. This function is called from the |
| 793 | * kernel allocators when a new block is allocated (kmem_cache_alloc, kmalloc, |
| 794 | * vmalloc etc.). |
| 795 | */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 796 | void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, |
| 797 | gfp_t gfp) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 798 | { |
| 799 | pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count); |
| 800 | |
| 801 | if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) |
| 802 | create_object((unsigned long)ptr, size, min_count, gfp); |
| 803 | else if (atomic_read(&kmemleak_early_log)) |
| 804 | log_early(KMEMLEAK_ALLOC, ptr, size, min_count, 0, 0); |
| 805 | } |
| 806 | EXPORT_SYMBOL_GPL(kmemleak_alloc); |
| 807 | |
| 808 | /* |
| 809 | * Memory freeing function callback. This function is called from the kernel |
| 810 | * allocators when a block is freed (kmem_cache_free, kfree, vfree etc.). |
| 811 | */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 812 | void __ref kmemleak_free(const void *ptr) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 813 | { |
| 814 | pr_debug("%s(0x%p)\n", __func__, ptr); |
| 815 | |
| 816 | if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 817 | delete_object_full((unsigned long)ptr); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 818 | else if (atomic_read(&kmemleak_early_log)) |
| 819 | log_early(KMEMLEAK_FREE, ptr, 0, 0, 0, 0); |
| 820 | } |
| 821 | EXPORT_SYMBOL_GPL(kmemleak_free); |
| 822 | |
| 823 | /* |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 824 | * Partial memory freeing function callback. This function is usually called |
| 825 | * from bootmem allocator when (part of) a memory block is freed. |
| 826 | */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 827 | void __ref kmemleak_free_part(const void *ptr, size_t size) |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 828 | { |
| 829 | pr_debug("%s(0x%p)\n", __func__, ptr); |
| 830 | |
| 831 | if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) |
| 832 | delete_object_part((unsigned long)ptr, size); |
| 833 | else if (atomic_read(&kmemleak_early_log)) |
| 834 | log_early(KMEMLEAK_FREE_PART, ptr, size, 0, 0, 0); |
| 835 | } |
| 836 | EXPORT_SYMBOL_GPL(kmemleak_free_part); |
| 837 | |
| 838 | /* |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 839 | * Mark an already allocated memory block as a false positive. This will cause |
| 840 | * the block to no longer be reported as leak and always be scanned. |
| 841 | */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 842 | void __ref kmemleak_not_leak(const void *ptr) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 843 | { |
| 844 | pr_debug("%s(0x%p)\n", __func__, ptr); |
| 845 | |
| 846 | if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) |
| 847 | make_gray_object((unsigned long)ptr); |
| 848 | else if (atomic_read(&kmemleak_early_log)) |
| 849 | log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0, 0, 0); |
| 850 | } |
| 851 | EXPORT_SYMBOL(kmemleak_not_leak); |
| 852 | |
| 853 | /* |
| 854 | * Ignore a memory block. This is usually done when it is known that the |
| 855 | * corresponding block is not a leak and does not contain any references to |
| 856 | * other allocated memory blocks. |
| 857 | */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 858 | void __ref kmemleak_ignore(const void *ptr) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 859 | { |
| 860 | pr_debug("%s(0x%p)\n", __func__, ptr); |
| 861 | |
| 862 | if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) |
| 863 | make_black_object((unsigned long)ptr); |
| 864 | else if (atomic_read(&kmemleak_early_log)) |
| 865 | log_early(KMEMLEAK_IGNORE, ptr, 0, 0, 0, 0); |
| 866 | } |
| 867 | EXPORT_SYMBOL(kmemleak_ignore); |
| 868 | |
| 869 | /* |
| 870 | * Limit the range to be scanned in an allocated memory block. |
| 871 | */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 872 | void __ref kmemleak_scan_area(const void *ptr, unsigned long offset, |
| 873 | size_t length, gfp_t gfp) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 874 | { |
| 875 | pr_debug("%s(0x%p)\n", __func__, ptr); |
| 876 | |
| 877 | if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) |
| 878 | add_scan_area((unsigned long)ptr, offset, length, gfp); |
| 879 | else if (atomic_read(&kmemleak_early_log)) |
| 880 | log_early(KMEMLEAK_SCAN_AREA, ptr, 0, 0, offset, length); |
| 881 | } |
| 882 | EXPORT_SYMBOL(kmemleak_scan_area); |
| 883 | |
| 884 | /* |
| 885 | * Inform kmemleak not to scan the given memory block. |
| 886 | */ |
Catalin Marinas | a6186d8 | 2009-08-27 14:29:16 +0100 | [diff] [blame] | 887 | void __ref kmemleak_no_scan(const void *ptr) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 888 | { |
| 889 | pr_debug("%s(0x%p)\n", __func__, ptr); |
| 890 | |
| 891 | if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) |
| 892 | object_no_scan((unsigned long)ptr); |
| 893 | else if (atomic_read(&kmemleak_early_log)) |
| 894 | log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0, 0, 0); |
| 895 | } |
| 896 | EXPORT_SYMBOL(kmemleak_no_scan); |
| 897 | |
| 898 | /* |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 899 | * Memory scanning is a long process and it needs to be interruptable. This |
| 900 | * function checks whether such interrupt condition occured. |
| 901 | */ |
| 902 | static int scan_should_stop(void) |
| 903 | { |
| 904 | if (!atomic_read(&kmemleak_enabled)) |
| 905 | return 1; |
| 906 | |
| 907 | /* |
| 908 | * This function may be called from either process or kthread context, |
| 909 | * hence the need to check for both stop conditions. |
| 910 | */ |
| 911 | if (current->mm) |
| 912 | return signal_pending(current); |
| 913 | else |
| 914 | return kthread_should_stop(); |
| 915 | |
| 916 | return 0; |
| 917 | } |
| 918 | |
| 919 | /* |
| 920 | * Scan a memory block (exclusive range) for valid pointers and add those |
| 921 | * found to the gray list. |
| 922 | */ |
| 923 | static void scan_block(void *_start, void *_end, |
Catalin Marinas | 4b8a967 | 2009-07-07 10:32:56 +0100 | [diff] [blame] | 924 | struct kmemleak_object *scanned, int allow_resched) |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 925 | { |
| 926 | unsigned long *ptr; |
| 927 | unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); |
| 928 | unsigned long *end = _end - (BYTES_PER_POINTER - 1); |
| 929 | |
| 930 | for (ptr = start; ptr < end; ptr++) { |
| 931 | unsigned long flags; |
| 932 | unsigned long pointer = *ptr; |
| 933 | struct kmemleak_object *object; |
| 934 | |
Catalin Marinas | 4b8a967 | 2009-07-07 10:32:56 +0100 | [diff] [blame] | 935 | if (allow_resched) |
| 936 | cond_resched(); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 937 | if (scan_should_stop()) |
| 938 | break; |
| 939 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 940 | object = find_and_get_object(pointer, 1); |
| 941 | if (!object) |
| 942 | continue; |
| 943 | if (object == scanned) { |
| 944 | /* self referenced, ignore */ |
| 945 | put_object(object); |
| 946 | continue; |
| 947 | } |
| 948 | |
| 949 | /* |
| 950 | * Avoid the lockdep recursive warning on object->lock being |
| 951 | * previously acquired in scan_object(). These locks are |
| 952 | * enclosed by scan_mutex. |
| 953 | */ |
| 954 | spin_lock_irqsave_nested(&object->lock, flags, |
| 955 | SINGLE_DEPTH_NESTING); |
| 956 | if (!color_white(object)) { |
| 957 | /* non-orphan, ignored or new */ |
| 958 | spin_unlock_irqrestore(&object->lock, flags); |
| 959 | put_object(object); |
| 960 | continue; |
| 961 | } |
| 962 | |
| 963 | /* |
| 964 | * Increase the object's reference count (number of pointers |
| 965 | * to the memory block). If this count reaches the required |
| 966 | * minimum, the object's color will become gray and it will be |
| 967 | * added to the gray_list. |
| 968 | */ |
| 969 | object->count++; |
| 970 | if (color_gray(object)) |
| 971 | list_add_tail(&object->gray_list, &gray_list); |
| 972 | else |
| 973 | put_object(object); |
| 974 | spin_unlock_irqrestore(&object->lock, flags); |
| 975 | } |
| 976 | } |
| 977 | |
| 978 | /* |
| 979 | * Scan a memory block corresponding to a kmemleak_object. A condition is |
| 980 | * that object->use_count >= 1. |
| 981 | */ |
| 982 | static void scan_object(struct kmemleak_object *object) |
| 983 | { |
| 984 | struct kmemleak_scan_area *area; |
| 985 | struct hlist_node *elem; |
| 986 | unsigned long flags; |
| 987 | |
| 988 | /* |
| 989 | * Once the object->lock is aquired, the corresponding memory block |
| 990 | * cannot be freed (the same lock is aquired in delete_object). |
| 991 | */ |
| 992 | spin_lock_irqsave(&object->lock, flags); |
| 993 | if (object->flags & OBJECT_NO_SCAN) |
| 994 | goto out; |
| 995 | if (!(object->flags & OBJECT_ALLOCATED)) |
| 996 | /* already freed object */ |
| 997 | goto out; |
Catalin Marinas | af98603 | 2009-08-27 14:29:12 +0100 | [diff] [blame] | 998 | if (hlist_empty(&object->area_list)) { |
| 999 | void *start = (void *)object->pointer; |
| 1000 | void *end = (void *)(object->pointer + object->size); |
| 1001 | |
| 1002 | while (start < end && (object->flags & OBJECT_ALLOCATED) && |
| 1003 | !(object->flags & OBJECT_NO_SCAN)) { |
| 1004 | scan_block(start, min(start + MAX_SCAN_SIZE, end), |
| 1005 | object, 0); |
| 1006 | start += MAX_SCAN_SIZE; |
| 1007 | |
| 1008 | spin_unlock_irqrestore(&object->lock, flags); |
| 1009 | cond_resched(); |
| 1010 | spin_lock_irqsave(&object->lock, flags); |
| 1011 | } |
| 1012 | } else |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1013 | hlist_for_each_entry(area, elem, &object->area_list, node) |
| 1014 | scan_block((void *)(object->pointer + area->offset), |
| 1015 | (void *)(object->pointer + area->offset |
Catalin Marinas | 4b8a967 | 2009-07-07 10:32:56 +0100 | [diff] [blame] | 1016 | + area->length), object, 0); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1017 | out: |
| 1018 | spin_unlock_irqrestore(&object->lock, flags); |
| 1019 | } |
| 1020 | |
| 1021 | /* |
| 1022 | * Scan data sections and all the referenced memory blocks allocated via the |
| 1023 | * kernel's standard allocators. This function must be called with the |
| 1024 | * scan_mutex held. |
| 1025 | */ |
| 1026 | static void kmemleak_scan(void) |
| 1027 | { |
| 1028 | unsigned long flags; |
| 1029 | struct kmemleak_object *object, *tmp; |
| 1030 | struct task_struct *task; |
| 1031 | int i; |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1032 | int new_leaks = 0; |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1033 | int gray_list_pass = 0; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1034 | |
Catalin Marinas | acf4968 | 2009-06-26 17:38:29 +0100 | [diff] [blame] | 1035 | jiffies_last_scan = jiffies; |
| 1036 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1037 | /* prepare the kmemleak_object's */ |
| 1038 | rcu_read_lock(); |
| 1039 | list_for_each_entry_rcu(object, &object_list, object_list) { |
| 1040 | spin_lock_irqsave(&object->lock, flags); |
| 1041 | #ifdef DEBUG |
| 1042 | /* |
| 1043 | * With a few exceptions there should be a maximum of |
| 1044 | * 1 reference to any object at this point. |
| 1045 | */ |
| 1046 | if (atomic_read(&object->use_count) > 1) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 1047 | pr_debug("object->use_count = %d\n", |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1048 | atomic_read(&object->use_count)); |
| 1049 | dump_object_info(object); |
| 1050 | } |
| 1051 | #endif |
| 1052 | /* reset the reference count (whiten the object) */ |
| 1053 | object->count = 0; |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1054 | object->flags &= ~OBJECT_NEW; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1055 | if (color_gray(object) && get_object(object)) |
| 1056 | list_add_tail(&object->gray_list, &gray_list); |
| 1057 | |
| 1058 | spin_unlock_irqrestore(&object->lock, flags); |
| 1059 | } |
| 1060 | rcu_read_unlock(); |
| 1061 | |
| 1062 | /* data/bss scanning */ |
Catalin Marinas | 4b8a967 | 2009-07-07 10:32:56 +0100 | [diff] [blame] | 1063 | scan_block(_sdata, _edata, NULL, 1); |
| 1064 | scan_block(__bss_start, __bss_stop, NULL, 1); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1065 | |
| 1066 | #ifdef CONFIG_SMP |
| 1067 | /* per-cpu sections scanning */ |
| 1068 | for_each_possible_cpu(i) |
| 1069 | scan_block(__per_cpu_start + per_cpu_offset(i), |
Catalin Marinas | 4b8a967 | 2009-07-07 10:32:56 +0100 | [diff] [blame] | 1070 | __per_cpu_end + per_cpu_offset(i), NULL, 1); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1071 | #endif |
| 1072 | |
| 1073 | /* |
| 1074 | * Struct page scanning for each node. The code below is not yet safe |
| 1075 | * with MEMORY_HOTPLUG. |
| 1076 | */ |
| 1077 | for_each_online_node(i) { |
| 1078 | pg_data_t *pgdat = NODE_DATA(i); |
| 1079 | unsigned long start_pfn = pgdat->node_start_pfn; |
| 1080 | unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages; |
| 1081 | unsigned long pfn; |
| 1082 | |
| 1083 | for (pfn = start_pfn; pfn < end_pfn; pfn++) { |
| 1084 | struct page *page; |
| 1085 | |
| 1086 | if (!pfn_valid(pfn)) |
| 1087 | continue; |
| 1088 | page = pfn_to_page(pfn); |
| 1089 | /* only scan if page is in use */ |
| 1090 | if (page_count(page) == 0) |
| 1091 | continue; |
Catalin Marinas | 4b8a967 | 2009-07-07 10:32:56 +0100 | [diff] [blame] | 1092 | scan_block(page, page + 1, NULL, 1); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1093 | } |
| 1094 | } |
| 1095 | |
| 1096 | /* |
| 1097 | * Scanning the task stacks may introduce false negatives and it is |
| 1098 | * not enabled by default. |
| 1099 | */ |
| 1100 | if (kmemleak_stack_scan) { |
| 1101 | read_lock(&tasklist_lock); |
| 1102 | for_each_process(task) |
| 1103 | scan_block(task_stack_page(task), |
Catalin Marinas | 4b8a967 | 2009-07-07 10:32:56 +0100 | [diff] [blame] | 1104 | task_stack_page(task) + THREAD_SIZE, |
| 1105 | NULL, 0); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1106 | read_unlock(&tasklist_lock); |
| 1107 | } |
| 1108 | |
| 1109 | /* |
| 1110 | * Scan the objects already referenced from the sections scanned |
| 1111 | * above. More objects will be referenced and, if there are no memory |
| 1112 | * leaks, all the objects will be scanned. The list traversal is safe |
| 1113 | * for both tail additions and removals from inside the loop. The |
| 1114 | * kmemleak objects cannot be freed from outside the loop because their |
| 1115 | * use_count was increased. |
| 1116 | */ |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1117 | repeat: |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1118 | object = list_entry(gray_list.next, typeof(*object), gray_list); |
| 1119 | while (&object->gray_list != &gray_list) { |
Ingo Molnar | 57d81f6 | 2009-07-01 09:43:53 +0200 | [diff] [blame] | 1120 | cond_resched(); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1121 | |
| 1122 | /* may add new objects to the list */ |
| 1123 | if (!scan_should_stop()) |
| 1124 | scan_object(object); |
| 1125 | |
| 1126 | tmp = list_entry(object->gray_list.next, typeof(*object), |
| 1127 | gray_list); |
| 1128 | |
| 1129 | /* remove the object from the list and release it */ |
| 1130 | list_del(&object->gray_list); |
| 1131 | put_object(object); |
| 1132 | |
| 1133 | object = tmp; |
| 1134 | } |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1135 | |
| 1136 | if (scan_should_stop() || ++gray_list_pass >= GRAY_LIST_PASSES) |
| 1137 | goto scan_end; |
| 1138 | |
| 1139 | /* |
| 1140 | * Check for new objects allocated during this scanning and add them |
| 1141 | * to the gray list. |
| 1142 | */ |
| 1143 | rcu_read_lock(); |
| 1144 | list_for_each_entry_rcu(object, &object_list, object_list) { |
| 1145 | spin_lock_irqsave(&object->lock, flags); |
| 1146 | if ((object->flags & OBJECT_NEW) && !color_black(object) && |
| 1147 | get_object(object)) { |
| 1148 | object->flags &= ~OBJECT_NEW; |
| 1149 | list_add_tail(&object->gray_list, &gray_list); |
| 1150 | } |
| 1151 | spin_unlock_irqrestore(&object->lock, flags); |
| 1152 | } |
| 1153 | rcu_read_unlock(); |
| 1154 | |
| 1155 | if (!list_empty(&gray_list)) |
| 1156 | goto repeat; |
| 1157 | |
| 1158 | scan_end: |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1159 | WARN_ON(!list_empty(&gray_list)); |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1160 | |
| 1161 | /* |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1162 | * If scanning was stopped or new objects were being allocated at a |
| 1163 | * higher rate than gray list scanning, do not report any new |
| 1164 | * unreferenced objects. |
Catalin Marinas | 17bb9e0 | 2009-06-29 17:13:56 +0100 | [diff] [blame] | 1165 | */ |
Catalin Marinas | 2587362 | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1166 | if (scan_should_stop() || gray_list_pass >= GRAY_LIST_PASSES) |
Catalin Marinas | 17bb9e0 | 2009-06-29 17:13:56 +0100 | [diff] [blame] | 1167 | return; |
| 1168 | |
| 1169 | /* |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1170 | * Scanning result reporting. |
| 1171 | */ |
| 1172 | rcu_read_lock(); |
| 1173 | list_for_each_entry_rcu(object, &object_list, object_list) { |
| 1174 | spin_lock_irqsave(&object->lock, flags); |
| 1175 | if (unreferenced_object(object) && |
| 1176 | !(object->flags & OBJECT_REPORTED)) { |
| 1177 | object->flags |= OBJECT_REPORTED; |
| 1178 | new_leaks++; |
| 1179 | } |
| 1180 | spin_unlock_irqrestore(&object->lock, flags); |
| 1181 | } |
| 1182 | rcu_read_unlock(); |
| 1183 | |
| 1184 | if (new_leaks) |
| 1185 | pr_info("%d new suspected memory leaks (see " |
| 1186 | "/sys/kernel/debug/kmemleak)\n", new_leaks); |
| 1187 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1188 | } |
| 1189 | |
| 1190 | /* |
| 1191 | * Thread function performing automatic memory scanning. Unreferenced objects |
| 1192 | * at the end of a memory scan are reported but only the first time. |
| 1193 | */ |
| 1194 | static int kmemleak_scan_thread(void *arg) |
| 1195 | { |
| 1196 | static int first_run = 1; |
| 1197 | |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 1198 | pr_info("Automatic memory scanning thread started\n"); |
Catalin Marinas | bf2a76b | 2009-07-07 10:32:55 +0100 | [diff] [blame] | 1199 | set_user_nice(current, 10); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1200 | |
| 1201 | /* |
| 1202 | * Wait before the first scan to allow the system to fully initialize. |
| 1203 | */ |
| 1204 | if (first_run) { |
| 1205 | first_run = 0; |
| 1206 | ssleep(SECS_FIRST_SCAN); |
| 1207 | } |
| 1208 | |
| 1209 | while (!kthread_should_stop()) { |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1210 | signed long timeout = jiffies_scan_wait; |
| 1211 | |
| 1212 | mutex_lock(&scan_mutex); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1213 | kmemleak_scan(); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1214 | mutex_unlock(&scan_mutex); |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1215 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1216 | /* wait before the next scan */ |
| 1217 | while (timeout && !kthread_should_stop()) |
| 1218 | timeout = schedule_timeout_interruptible(timeout); |
| 1219 | } |
| 1220 | |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 1221 | pr_info("Automatic memory scanning thread ended\n"); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1222 | |
| 1223 | return 0; |
| 1224 | } |
| 1225 | |
| 1226 | /* |
| 1227 | * Start the automatic memory scanning thread. This function must be called |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1228 | * with the scan_mutex held. |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1229 | */ |
| 1230 | void start_scan_thread(void) |
| 1231 | { |
| 1232 | if (scan_thread) |
| 1233 | return; |
| 1234 | scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); |
| 1235 | if (IS_ERR(scan_thread)) { |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 1236 | pr_warning("Failed to create the scan thread\n"); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1237 | scan_thread = NULL; |
| 1238 | } |
| 1239 | } |
| 1240 | |
| 1241 | /* |
| 1242 | * Stop the automatic memory scanning thread. This function must be called |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1243 | * with the scan_mutex held. |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1244 | */ |
| 1245 | void stop_scan_thread(void) |
| 1246 | { |
| 1247 | if (scan_thread) { |
| 1248 | kthread_stop(scan_thread); |
| 1249 | scan_thread = NULL; |
| 1250 | } |
| 1251 | } |
| 1252 | |
| 1253 | /* |
| 1254 | * Iterate over the object_list and return the first valid object at or after |
| 1255 | * the required position with its use_count incremented. The function triggers |
| 1256 | * a memory scanning when the pos argument points to the first position. |
| 1257 | */ |
| 1258 | static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) |
| 1259 | { |
| 1260 | struct kmemleak_object *object; |
| 1261 | loff_t n = *pos; |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1262 | int err; |
| 1263 | |
| 1264 | err = mutex_lock_interruptible(&scan_mutex); |
| 1265 | if (err < 0) |
| 1266 | return ERR_PTR(err); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1267 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1268 | rcu_read_lock(); |
| 1269 | list_for_each_entry_rcu(object, &object_list, object_list) { |
| 1270 | if (n-- > 0) |
| 1271 | continue; |
| 1272 | if (get_object(object)) |
| 1273 | goto out; |
| 1274 | } |
| 1275 | object = NULL; |
| 1276 | out: |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1277 | return object; |
| 1278 | } |
| 1279 | |
| 1280 | /* |
| 1281 | * Return the next object in the object_list. The function decrements the |
| 1282 | * use_count of the previous object and increases that of the next one. |
| 1283 | */ |
| 1284 | static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
| 1285 | { |
| 1286 | struct kmemleak_object *prev_obj = v; |
| 1287 | struct kmemleak_object *next_obj = NULL; |
| 1288 | struct list_head *n = &prev_obj->object_list; |
| 1289 | |
| 1290 | ++(*pos); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1291 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1292 | list_for_each_continue_rcu(n, &object_list) { |
| 1293 | next_obj = list_entry(n, struct kmemleak_object, object_list); |
| 1294 | if (get_object(next_obj)) |
| 1295 | break; |
| 1296 | } |
Catalin Marinas | 288c857 | 2009-07-07 10:32:57 +0100 | [diff] [blame] | 1297 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1298 | put_object(prev_obj); |
| 1299 | return next_obj; |
| 1300 | } |
| 1301 | |
| 1302 | /* |
| 1303 | * Decrement the use_count of the last object required, if any. |
| 1304 | */ |
| 1305 | static void kmemleak_seq_stop(struct seq_file *seq, void *v) |
| 1306 | { |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1307 | if (!IS_ERR(v)) { |
| 1308 | /* |
| 1309 | * kmemleak_seq_start may return ERR_PTR if the scan_mutex |
| 1310 | * waiting was interrupted, so only release it if !IS_ERR. |
| 1311 | */ |
Catalin Marinas | f5886c7 | 2009-07-29 16:26:57 +0100 | [diff] [blame] | 1312 | rcu_read_unlock(); |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1313 | mutex_unlock(&scan_mutex); |
| 1314 | if (v) |
| 1315 | put_object(v); |
| 1316 | } |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1317 | } |
| 1318 | |
| 1319 | /* |
| 1320 | * Print the information for an unreferenced object to the seq file. |
| 1321 | */ |
| 1322 | static int kmemleak_seq_show(struct seq_file *seq, void *v) |
| 1323 | { |
| 1324 | struct kmemleak_object *object = v; |
| 1325 | unsigned long flags; |
| 1326 | |
| 1327 | spin_lock_irqsave(&object->lock, flags); |
Catalin Marinas | 288c857 | 2009-07-07 10:32:57 +0100 | [diff] [blame] | 1328 | if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) |
Catalin Marinas | 17bb9e0 | 2009-06-29 17:13:56 +0100 | [diff] [blame] | 1329 | print_unreferenced(seq, object); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1330 | spin_unlock_irqrestore(&object->lock, flags); |
| 1331 | return 0; |
| 1332 | } |
| 1333 | |
| 1334 | static const struct seq_operations kmemleak_seq_ops = { |
| 1335 | .start = kmemleak_seq_start, |
| 1336 | .next = kmemleak_seq_next, |
| 1337 | .stop = kmemleak_seq_stop, |
| 1338 | .show = kmemleak_seq_show, |
| 1339 | }; |
| 1340 | |
| 1341 | static int kmemleak_open(struct inode *inode, struct file *file) |
| 1342 | { |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1343 | if (!atomic_read(&kmemleak_enabled)) |
| 1344 | return -EBUSY; |
| 1345 | |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1346 | return seq_open(file, &kmemleak_seq_ops); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1347 | } |
| 1348 | |
| 1349 | static int kmemleak_release(struct inode *inode, struct file *file) |
| 1350 | { |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1351 | return seq_release(inode, file); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1352 | } |
| 1353 | |
Catalin Marinas | 189d84e | 2009-08-27 14:29:15 +0100 | [diff] [blame] | 1354 | static int dump_str_object_info(const char *str) |
| 1355 | { |
| 1356 | unsigned long flags; |
| 1357 | struct kmemleak_object *object; |
| 1358 | unsigned long addr; |
| 1359 | |
| 1360 | addr= simple_strtoul(str, NULL, 0); |
| 1361 | object = find_and_get_object(addr, 0); |
| 1362 | if (!object) { |
| 1363 | pr_info("Unknown object at 0x%08lx\n", addr); |
| 1364 | return -EINVAL; |
| 1365 | } |
| 1366 | |
| 1367 | spin_lock_irqsave(&object->lock, flags); |
| 1368 | dump_object_info(object); |
| 1369 | spin_unlock_irqrestore(&object->lock, flags); |
| 1370 | |
| 1371 | put_object(object); |
| 1372 | return 0; |
| 1373 | } |
| 1374 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1375 | /* |
| 1376 | * File write operation to configure kmemleak at run-time. The following |
| 1377 | * commands can be written to the /sys/kernel/debug/kmemleak file: |
| 1378 | * off - disable kmemleak (irreversible) |
| 1379 | * stack=on - enable the task stacks scanning |
| 1380 | * stack=off - disable the tasks stacks scanning |
| 1381 | * scan=on - start the automatic memory scanning thread |
| 1382 | * scan=off - stop the automatic memory scanning thread |
| 1383 | * scan=... - set the automatic memory scanning period in seconds (0 to |
| 1384 | * disable it) |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1385 | * scan - trigger a memory scan |
Catalin Marinas | 189d84e | 2009-08-27 14:29:15 +0100 | [diff] [blame] | 1386 | * dump=... - dump information about the object found at the given address |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1387 | */ |
| 1388 | static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, |
| 1389 | size_t size, loff_t *ppos) |
| 1390 | { |
| 1391 | char buf[64]; |
| 1392 | int buf_size; |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1393 | int ret; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1394 | |
| 1395 | buf_size = min(size, (sizeof(buf) - 1)); |
| 1396 | if (strncpy_from_user(buf, user_buf, buf_size) < 0) |
| 1397 | return -EFAULT; |
| 1398 | buf[buf_size] = 0; |
| 1399 | |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1400 | ret = mutex_lock_interruptible(&scan_mutex); |
| 1401 | if (ret < 0) |
| 1402 | return ret; |
| 1403 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1404 | if (strncmp(buf, "off", 3) == 0) |
| 1405 | kmemleak_disable(); |
| 1406 | else if (strncmp(buf, "stack=on", 8) == 0) |
| 1407 | kmemleak_stack_scan = 1; |
| 1408 | else if (strncmp(buf, "stack=off", 9) == 0) |
| 1409 | kmemleak_stack_scan = 0; |
| 1410 | else if (strncmp(buf, "scan=on", 7) == 0) |
| 1411 | start_scan_thread(); |
| 1412 | else if (strncmp(buf, "scan=off", 8) == 0) |
| 1413 | stop_scan_thread(); |
| 1414 | else if (strncmp(buf, "scan=", 5) == 0) { |
| 1415 | unsigned long secs; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1416 | |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1417 | ret = strict_strtoul(buf + 5, 0, &secs); |
| 1418 | if (ret < 0) |
| 1419 | goto out; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1420 | stop_scan_thread(); |
| 1421 | if (secs) { |
| 1422 | jiffies_scan_wait = msecs_to_jiffies(secs * 1000); |
| 1423 | start_scan_thread(); |
| 1424 | } |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1425 | } else if (strncmp(buf, "scan", 4) == 0) |
| 1426 | kmemleak_scan(); |
Catalin Marinas | 189d84e | 2009-08-27 14:29:15 +0100 | [diff] [blame] | 1427 | else if (strncmp(buf, "dump=", 5) == 0) |
| 1428 | ret = dump_str_object_info(buf + 5); |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1429 | else |
Catalin Marinas | b87324d | 2009-07-07 10:32:58 +0100 | [diff] [blame] | 1430 | ret = -EINVAL; |
| 1431 | |
| 1432 | out: |
| 1433 | mutex_unlock(&scan_mutex); |
| 1434 | if (ret < 0) |
| 1435 | return ret; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1436 | |
| 1437 | /* ignore the rest of the buffer, only one command at a time */ |
| 1438 | *ppos += size; |
| 1439 | return size; |
| 1440 | } |
| 1441 | |
| 1442 | static const struct file_operations kmemleak_fops = { |
| 1443 | .owner = THIS_MODULE, |
| 1444 | .open = kmemleak_open, |
| 1445 | .read = seq_read, |
| 1446 | .write = kmemleak_write, |
| 1447 | .llseek = seq_lseek, |
| 1448 | .release = kmemleak_release, |
| 1449 | }; |
| 1450 | |
| 1451 | /* |
| 1452 | * Perform the freeing of the kmemleak internal objects after waiting for any |
| 1453 | * current memory scan to complete. |
| 1454 | */ |
| 1455 | static int kmemleak_cleanup_thread(void *arg) |
| 1456 | { |
| 1457 | struct kmemleak_object *object; |
| 1458 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1459 | mutex_lock(&scan_mutex); |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1460 | stop_scan_thread(); |
| 1461 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1462 | rcu_read_lock(); |
| 1463 | list_for_each_entry_rcu(object, &object_list, object_list) |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 1464 | delete_object_full(object->pointer); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1465 | rcu_read_unlock(); |
| 1466 | mutex_unlock(&scan_mutex); |
| 1467 | |
| 1468 | return 0; |
| 1469 | } |
| 1470 | |
| 1471 | /* |
| 1472 | * Start the clean-up thread. |
| 1473 | */ |
| 1474 | static void kmemleak_cleanup(void) |
| 1475 | { |
| 1476 | struct task_struct *cleanup_thread; |
| 1477 | |
| 1478 | cleanup_thread = kthread_run(kmemleak_cleanup_thread, NULL, |
| 1479 | "kmemleak-clean"); |
| 1480 | if (IS_ERR(cleanup_thread)) |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 1481 | pr_warning("Failed to create the clean-up thread\n"); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1482 | } |
| 1483 | |
| 1484 | /* |
| 1485 | * Disable kmemleak. No memory allocation/freeing will be traced once this |
| 1486 | * function is called. Disabling kmemleak is an irreversible operation. |
| 1487 | */ |
| 1488 | static void kmemleak_disable(void) |
| 1489 | { |
| 1490 | /* atomically check whether it was already invoked */ |
| 1491 | if (atomic_cmpxchg(&kmemleak_error, 0, 1)) |
| 1492 | return; |
| 1493 | |
| 1494 | /* stop any memory operation tracing */ |
| 1495 | atomic_set(&kmemleak_early_log, 0); |
| 1496 | atomic_set(&kmemleak_enabled, 0); |
| 1497 | |
| 1498 | /* check whether it is too early for a kernel thread */ |
| 1499 | if (atomic_read(&kmemleak_initialized)) |
| 1500 | kmemleak_cleanup(); |
| 1501 | |
| 1502 | pr_info("Kernel memory leak detector disabled\n"); |
| 1503 | } |
| 1504 | |
| 1505 | /* |
| 1506 | * Allow boot-time kmemleak disabling (enabled by default). |
| 1507 | */ |
| 1508 | static int kmemleak_boot_config(char *str) |
| 1509 | { |
| 1510 | if (!str) |
| 1511 | return -EINVAL; |
| 1512 | if (strcmp(str, "off") == 0) |
| 1513 | kmemleak_disable(); |
| 1514 | else if (strcmp(str, "on") != 0) |
| 1515 | return -EINVAL; |
| 1516 | return 0; |
| 1517 | } |
| 1518 | early_param("kmemleak", kmemleak_boot_config); |
| 1519 | |
| 1520 | /* |
Catalin Marinas | 2030117 | 2009-06-17 18:29:04 +0100 | [diff] [blame] | 1521 | * Kmemleak initialization. |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1522 | */ |
| 1523 | void __init kmemleak_init(void) |
| 1524 | { |
| 1525 | int i; |
| 1526 | unsigned long flags; |
| 1527 | |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1528 | jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); |
| 1529 | jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); |
| 1530 | |
| 1531 | object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); |
| 1532 | scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); |
| 1533 | INIT_PRIO_TREE_ROOT(&object_tree_root); |
| 1534 | |
| 1535 | /* the kernel is still in UP mode, so disabling the IRQs is enough */ |
| 1536 | local_irq_save(flags); |
| 1537 | if (!atomic_read(&kmemleak_error)) { |
| 1538 | atomic_set(&kmemleak_enabled, 1); |
| 1539 | atomic_set(&kmemleak_early_log, 0); |
| 1540 | } |
| 1541 | local_irq_restore(flags); |
| 1542 | |
| 1543 | /* |
| 1544 | * This is the point where tracking allocations is safe. Automatic |
| 1545 | * scanning is started during the late initcall. Add the early logged |
| 1546 | * callbacks to the kmemleak infrastructure. |
| 1547 | */ |
| 1548 | for (i = 0; i < crt_early_log; i++) { |
| 1549 | struct early_log *log = &early_log[i]; |
| 1550 | |
| 1551 | switch (log->op_type) { |
| 1552 | case KMEMLEAK_ALLOC: |
Catalin Marinas | fd67896 | 2009-08-27 14:29:17 +0100 | [diff] [blame] | 1553 | early_alloc(log); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1554 | break; |
| 1555 | case KMEMLEAK_FREE: |
| 1556 | kmemleak_free(log->ptr); |
| 1557 | break; |
Catalin Marinas | 53238a6 | 2009-07-07 10:33:00 +0100 | [diff] [blame] | 1558 | case KMEMLEAK_FREE_PART: |
| 1559 | kmemleak_free_part(log->ptr, log->size); |
| 1560 | break; |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1561 | case KMEMLEAK_NOT_LEAK: |
| 1562 | kmemleak_not_leak(log->ptr); |
| 1563 | break; |
| 1564 | case KMEMLEAK_IGNORE: |
| 1565 | kmemleak_ignore(log->ptr); |
| 1566 | break; |
| 1567 | case KMEMLEAK_SCAN_AREA: |
| 1568 | kmemleak_scan_area(log->ptr, log->offset, log->length, |
| 1569 | GFP_KERNEL); |
| 1570 | break; |
| 1571 | case KMEMLEAK_NO_SCAN: |
| 1572 | kmemleak_no_scan(log->ptr); |
| 1573 | break; |
| 1574 | default: |
| 1575 | WARN_ON(1); |
| 1576 | } |
| 1577 | } |
| 1578 | } |
| 1579 | |
| 1580 | /* |
| 1581 | * Late initialization function. |
| 1582 | */ |
| 1583 | static int __init kmemleak_late_init(void) |
| 1584 | { |
| 1585 | struct dentry *dentry; |
| 1586 | |
| 1587 | atomic_set(&kmemleak_initialized, 1); |
| 1588 | |
| 1589 | if (atomic_read(&kmemleak_error)) { |
| 1590 | /* |
| 1591 | * Some error occured and kmemleak was disabled. There is a |
| 1592 | * small chance that kmemleak_disable() was called immediately |
| 1593 | * after setting kmemleak_initialized and we may end up with |
| 1594 | * two clean-up threads but serialized by scan_mutex. |
| 1595 | */ |
| 1596 | kmemleak_cleanup(); |
| 1597 | return -ENOMEM; |
| 1598 | } |
| 1599 | |
| 1600 | dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL, |
| 1601 | &kmemleak_fops); |
| 1602 | if (!dentry) |
Joe Perches | ae28106 | 2009-06-23 14:40:26 +0100 | [diff] [blame] | 1603 | pr_warning("Failed to create the debugfs kmemleak file\n"); |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1604 | mutex_lock(&scan_mutex); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1605 | start_scan_thread(); |
Catalin Marinas | 4698c1f | 2009-06-26 17:38:27 +0100 | [diff] [blame] | 1606 | mutex_unlock(&scan_mutex); |
Catalin Marinas | 3c7b4e6 | 2009-06-11 13:22:39 +0100 | [diff] [blame] | 1607 | |
| 1608 | pr_info("Kernel memory leak detector initialized\n"); |
| 1609 | |
| 1610 | return 0; |
| 1611 | } |
| 1612 | late_initcall(kmemleak_late_init); |