kmemleak.c revision 4698c1f2bbe44ce852ef1a6716973c1f5401a4c4
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 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 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 64#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 65 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 */ 106#define REPORTS_NR 50 /* maximum number of reported leaks */ 107#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ 108#define MSECS_SCAN_YIELD 10 /* CPU yielding period */ 109#define SECS_FIRST_SCAN 60 /* delay before the first scan */ 110#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ 111 112#define BYTES_PER_POINTER sizeof(void *) 113 114/* GFP bitmask for kmemleak internal allocations */ 115#define GFP_KMEMLEAK_MASK (GFP_KERNEL | GFP_ATOMIC) 116 117/* scanning area inside a memory block */ 118struct 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 */ 132struct 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) 162 163/* the list of all allocated objects */ 164static LIST_HEAD(object_list); 165/* the list of gray-colored objects (see color_gray comment below) */ 166static LIST_HEAD(gray_list); 167/* prio search tree for object boundaries */ 168static struct prio_tree_root object_tree_root; 169/* rw_lock protecting the access to object_list and prio_tree_root */ 170static DEFINE_RWLOCK(kmemleak_lock); 171 172/* allocation caches for kmemleak internal data */ 173static struct kmem_cache *object_cache; 174static struct kmem_cache *scan_area_cache; 175 176/* set if tracing memory operations is enabled */ 177static atomic_t kmemleak_enabled = ATOMIC_INIT(0); 178/* set in the late_initcall if there were no errors */ 179static atomic_t kmemleak_initialized = ATOMIC_INIT(0); 180/* enables or disables early logging of the memory operations */ 181static atomic_t kmemleak_early_log = ATOMIC_INIT(1); 182/* set if a fata kmemleak error has occurred */ 183static atomic_t kmemleak_error = ATOMIC_INIT(0); 184 185/* minimum and maximum address that may be valid pointers */ 186static unsigned long min_addr = ULONG_MAX; 187static unsigned long max_addr; 188 189/* used for yielding the CPU to other tasks during scanning */ 190static unsigned long next_scan_yield; 191static struct task_struct *scan_thread; 192static unsigned long jiffies_scan_yield; 193static unsigned long jiffies_min_age; 194/* delay between automatic memory scannings */ 195static signed long jiffies_scan_wait; 196/* enables or disables the task stacks scanning */ 197static int kmemleak_stack_scan = 1; 198/* protects the memory scanning, parameters and debug/kmemleak file access */ 199static DEFINE_MUTEX(scan_mutex); 200 201/* number of leaks reported (for limitation purposes) */ 202static int reported_leaks; 203 204/* 205 * Early object allocation/freeing logging. Kmemleak is initialized after the 206 * kernel allocator. However, both the kernel allocator and kmemleak may 207 * allocate memory blocks which need to be tracked. Kmemleak defines an 208 * arbitrary buffer to hold the allocation/freeing information before it is 209 * fully initialized. 210 */ 211 212/* kmemleak operation type for early logging */ 213enum { 214 KMEMLEAK_ALLOC, 215 KMEMLEAK_FREE, 216 KMEMLEAK_NOT_LEAK, 217 KMEMLEAK_IGNORE, 218 KMEMLEAK_SCAN_AREA, 219 KMEMLEAK_NO_SCAN 220}; 221 222/* 223 * Structure holding the information passed to kmemleak callbacks during the 224 * early logging. 225 */ 226struct early_log { 227 int op_type; /* kmemleak operation type */ 228 const void *ptr; /* allocated/freed memory block */ 229 size_t size; /* memory block size */ 230 int min_count; /* minimum reference count */ 231 unsigned long offset; /* scan area offset */ 232 size_t length; /* scan area length */ 233}; 234 235/* early logging buffer and current position */ 236static struct early_log early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE]; 237static int crt_early_log; 238 239static void kmemleak_disable(void); 240 241/* 242 * Print a warning and dump the stack trace. 243 */ 244#define kmemleak_warn(x...) do { \ 245 pr_warning(x); \ 246 dump_stack(); \ 247} while (0) 248 249/* 250 * Macro invoked when a serious kmemleak condition occured and cannot be 251 * recovered from. Kmemleak will be disabled and further allocation/freeing 252 * tracing no longer available. 253 */ 254#define kmemleak_stop(x...) do { \ 255 kmemleak_warn(x); \ 256 kmemleak_disable(); \ 257} while (0) 258 259/* 260 * Object colors, encoded with count and min_count: 261 * - white - orphan object, not enough references to it (count < min_count) 262 * - gray - not orphan, not marked as false positive (min_count == 0) or 263 * sufficient references to it (count >= min_count) 264 * - black - ignore, it doesn't contain references (e.g. text section) 265 * (min_count == -1). No function defined for this color. 266 * Newly created objects don't have any color assigned (object->count == -1) 267 * before the next memory scan when they become white. 268 */ 269static int color_white(const struct kmemleak_object *object) 270{ 271 return object->count != -1 && object->count < object->min_count; 272} 273 274static int color_gray(const struct kmemleak_object *object) 275{ 276 return object->min_count != -1 && object->count >= object->min_count; 277} 278 279/* 280 * Objects are considered unreferenced only if their color is white, they have 281 * not be deleted and have a minimum age to avoid false positives caused by 282 * pointers temporarily stored in CPU registers. 283 */ 284static int unreferenced_object(struct kmemleak_object *object) 285{ 286 return (object->flags & OBJECT_ALLOCATED) && color_white(object) && 287 time_is_before_eq_jiffies(object->jiffies + jiffies_min_age); 288} 289 290/* 291 * Printing of the unreferenced objects information to the seq file. The 292 * print_unreferenced function must be called with the object->lock held. 293 */ 294static void print_unreferenced(struct seq_file *seq, 295 struct kmemleak_object *object) 296{ 297 int i; 298 299 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", 300 object->pointer, object->size); 301 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", 302 object->comm, object->pid, object->jiffies); 303 seq_printf(seq, " backtrace:\n"); 304 305 for (i = 0; i < object->trace_len; i++) { 306 void *ptr = (void *)object->trace[i]; 307 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); 308 } 309} 310 311/* 312 * Print the kmemleak_object information. This function is used mainly for 313 * debugging special cases when kmemleak operations. It must be called with 314 * the object->lock held. 315 */ 316static void dump_object_info(struct kmemleak_object *object) 317{ 318 struct stack_trace trace; 319 320 trace.nr_entries = object->trace_len; 321 trace.entries = object->trace; 322 323 pr_notice("Object 0x%08lx (size %zu):\n", 324 object->tree_node.start, object->size); 325 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", 326 object->comm, object->pid, object->jiffies); 327 pr_notice(" min_count = %d\n", object->min_count); 328 pr_notice(" count = %d\n", object->count); 329 pr_notice(" backtrace:\n"); 330 print_stack_trace(&trace, 4); 331} 332 333/* 334 * Look-up a memory block metadata (kmemleak_object) in the priority search 335 * tree based on a pointer value. If alias is 0, only values pointing to the 336 * beginning of the memory block are allowed. The kmemleak_lock must be held 337 * when calling this function. 338 */ 339static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) 340{ 341 struct prio_tree_node *node; 342 struct prio_tree_iter iter; 343 struct kmemleak_object *object; 344 345 prio_tree_iter_init(&iter, &object_tree_root, ptr, ptr); 346 node = prio_tree_next(&iter); 347 if (node) { 348 object = prio_tree_entry(node, struct kmemleak_object, 349 tree_node); 350 if (!alias && object->pointer != ptr) { 351 kmemleak_warn("Found object by alias"); 352 object = NULL; 353 } 354 } else 355 object = NULL; 356 357 return object; 358} 359 360/* 361 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note 362 * that once an object's use_count reached 0, the RCU freeing was already 363 * registered and the object should no longer be used. This function must be 364 * called under the protection of rcu_read_lock(). 365 */ 366static int get_object(struct kmemleak_object *object) 367{ 368 return atomic_inc_not_zero(&object->use_count); 369} 370 371/* 372 * RCU callback to free a kmemleak_object. 373 */ 374static void free_object_rcu(struct rcu_head *rcu) 375{ 376 struct hlist_node *elem, *tmp; 377 struct kmemleak_scan_area *area; 378 struct kmemleak_object *object = 379 container_of(rcu, struct kmemleak_object, rcu); 380 381 /* 382 * Once use_count is 0 (guaranteed by put_object), there is no other 383 * code accessing this object, hence no need for locking. 384 */ 385 hlist_for_each_entry_safe(area, elem, tmp, &object->area_list, node) { 386 hlist_del(elem); 387 kmem_cache_free(scan_area_cache, area); 388 } 389 kmem_cache_free(object_cache, object); 390} 391 392/* 393 * Decrement the object use_count. Once the count is 0, free the object using 394 * an RCU callback. Since put_object() may be called via the kmemleak_free() -> 395 * delete_object() path, the delayed RCU freeing ensures that there is no 396 * recursive call to the kernel allocator. Lock-less RCU object_list traversal 397 * is also possible. 398 */ 399static void put_object(struct kmemleak_object *object) 400{ 401 if (!atomic_dec_and_test(&object->use_count)) 402 return; 403 404 /* should only get here after delete_object was called */ 405 WARN_ON(object->flags & OBJECT_ALLOCATED); 406 407 call_rcu(&object->rcu, free_object_rcu); 408} 409 410/* 411 * Look up an object in the prio search tree and increase its use_count. 412 */ 413static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) 414{ 415 unsigned long flags; 416 struct kmemleak_object *object = NULL; 417 418 rcu_read_lock(); 419 read_lock_irqsave(&kmemleak_lock, flags); 420 if (ptr >= min_addr && ptr < max_addr) 421 object = lookup_object(ptr, alias); 422 read_unlock_irqrestore(&kmemleak_lock, flags); 423 424 /* check whether the object is still available */ 425 if (object && !get_object(object)) 426 object = NULL; 427 rcu_read_unlock(); 428 429 return object; 430} 431 432/* 433 * Create the metadata (struct kmemleak_object) corresponding to an allocated 434 * memory block and add it to the object_list and object_tree_root. 435 */ 436static void create_object(unsigned long ptr, size_t size, int min_count, 437 gfp_t gfp) 438{ 439 unsigned long flags; 440 struct kmemleak_object *object; 441 struct prio_tree_node *node; 442 struct stack_trace trace; 443 444 object = kmem_cache_alloc(object_cache, gfp & GFP_KMEMLEAK_MASK); 445 if (!object) { 446 kmemleak_stop("Cannot allocate a kmemleak_object structure\n"); 447 return; 448 } 449 450 INIT_LIST_HEAD(&object->object_list); 451 INIT_LIST_HEAD(&object->gray_list); 452 INIT_HLIST_HEAD(&object->area_list); 453 spin_lock_init(&object->lock); 454 atomic_set(&object->use_count, 1); 455 object->flags = OBJECT_ALLOCATED; 456 object->pointer = ptr; 457 object->size = size; 458 object->min_count = min_count; 459 object->count = -1; /* no color initially */ 460 object->jiffies = jiffies; 461 462 /* task information */ 463 if (in_irq()) { 464 object->pid = 0; 465 strncpy(object->comm, "hardirq", sizeof(object->comm)); 466 } else if (in_softirq()) { 467 object->pid = 0; 468 strncpy(object->comm, "softirq", sizeof(object->comm)); 469 } else { 470 object->pid = current->pid; 471 /* 472 * There is a small chance of a race with set_task_comm(), 473 * however using get_task_comm() here may cause locking 474 * dependency issues with current->alloc_lock. In the worst 475 * case, the command line is not correct. 476 */ 477 strncpy(object->comm, current->comm, sizeof(object->comm)); 478 } 479 480 /* kernel backtrace */ 481 trace.max_entries = MAX_TRACE; 482 trace.nr_entries = 0; 483 trace.entries = object->trace; 484 trace.skip = 1; 485 save_stack_trace(&trace); 486 object->trace_len = trace.nr_entries; 487 488 INIT_PRIO_TREE_NODE(&object->tree_node); 489 object->tree_node.start = ptr; 490 object->tree_node.last = ptr + size - 1; 491 492 write_lock_irqsave(&kmemleak_lock, flags); 493 min_addr = min(min_addr, ptr); 494 max_addr = max(max_addr, ptr + size); 495 node = prio_tree_insert(&object_tree_root, &object->tree_node); 496 /* 497 * The code calling the kernel does not yet have the pointer to the 498 * memory block to be able to free it. However, we still hold the 499 * kmemleak_lock here in case parts of the kernel started freeing 500 * random memory blocks. 501 */ 502 if (node != &object->tree_node) { 503 unsigned long flags; 504 505 kmemleak_stop("Cannot insert 0x%lx into the object search tree " 506 "(already existing)\n", ptr); 507 object = lookup_object(ptr, 1); 508 spin_lock_irqsave(&object->lock, flags); 509 dump_object_info(object); 510 spin_unlock_irqrestore(&object->lock, flags); 511 512 goto out; 513 } 514 list_add_tail_rcu(&object->object_list, &object_list); 515out: 516 write_unlock_irqrestore(&kmemleak_lock, flags); 517} 518 519/* 520 * Remove the metadata (struct kmemleak_object) for a memory block from the 521 * object_list and object_tree_root and decrement its use_count. 522 */ 523static void delete_object(unsigned long ptr) 524{ 525 unsigned long flags; 526 struct kmemleak_object *object; 527 528 write_lock_irqsave(&kmemleak_lock, flags); 529 object = lookup_object(ptr, 0); 530 if (!object) { 531 kmemleak_warn("Freeing unknown object at 0x%08lx\n", 532 ptr); 533 write_unlock_irqrestore(&kmemleak_lock, flags); 534 return; 535 } 536 prio_tree_remove(&object_tree_root, &object->tree_node); 537 list_del_rcu(&object->object_list); 538 write_unlock_irqrestore(&kmemleak_lock, flags); 539 540 WARN_ON(!(object->flags & OBJECT_ALLOCATED)); 541 WARN_ON(atomic_read(&object->use_count) < 1); 542 543 /* 544 * Locking here also ensures that the corresponding memory block 545 * cannot be freed when it is being scanned. 546 */ 547 spin_lock_irqsave(&object->lock, flags); 548 object->flags &= ~OBJECT_ALLOCATED; 549 spin_unlock_irqrestore(&object->lock, flags); 550 put_object(object); 551} 552 553/* 554 * Make a object permanently as gray-colored so that it can no longer be 555 * reported as a leak. This is used in general to mark a false positive. 556 */ 557static void make_gray_object(unsigned long ptr) 558{ 559 unsigned long flags; 560 struct kmemleak_object *object; 561 562 object = find_and_get_object(ptr, 0); 563 if (!object) { 564 kmemleak_warn("Graying unknown object at 0x%08lx\n", ptr); 565 return; 566 } 567 568 spin_lock_irqsave(&object->lock, flags); 569 object->min_count = 0; 570 spin_unlock_irqrestore(&object->lock, flags); 571 put_object(object); 572} 573 574/* 575 * Mark the object as black-colored so that it is ignored from scans and 576 * reporting. 577 */ 578static void make_black_object(unsigned long ptr) 579{ 580 unsigned long flags; 581 struct kmemleak_object *object; 582 583 object = find_and_get_object(ptr, 0); 584 if (!object) { 585 kmemleak_warn("Blacking unknown object at 0x%08lx\n", ptr); 586 return; 587 } 588 589 spin_lock_irqsave(&object->lock, flags); 590 object->min_count = -1; 591 spin_unlock_irqrestore(&object->lock, flags); 592 put_object(object); 593} 594 595/* 596 * Add a scanning area to the object. If at least one such area is added, 597 * kmemleak will only scan these ranges rather than the whole memory block. 598 */ 599static void add_scan_area(unsigned long ptr, unsigned long offset, 600 size_t length, gfp_t gfp) 601{ 602 unsigned long flags; 603 struct kmemleak_object *object; 604 struct kmemleak_scan_area *area; 605 606 object = find_and_get_object(ptr, 0); 607 if (!object) { 608 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", 609 ptr); 610 return; 611 } 612 613 area = kmem_cache_alloc(scan_area_cache, gfp & GFP_KMEMLEAK_MASK); 614 if (!area) { 615 kmemleak_warn("Cannot allocate a scan area\n"); 616 goto out; 617 } 618 619 spin_lock_irqsave(&object->lock, flags); 620 if (offset + length > object->size) { 621 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); 622 dump_object_info(object); 623 kmem_cache_free(scan_area_cache, area); 624 goto out_unlock; 625 } 626 627 INIT_HLIST_NODE(&area->node); 628 area->offset = offset; 629 area->length = length; 630 631 hlist_add_head(&area->node, &object->area_list); 632out_unlock: 633 spin_unlock_irqrestore(&object->lock, flags); 634out: 635 put_object(object); 636} 637 638/* 639 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give 640 * pointer. Such object will not be scanned by kmemleak but references to it 641 * are searched. 642 */ 643static void object_no_scan(unsigned long ptr) 644{ 645 unsigned long flags; 646 struct kmemleak_object *object; 647 648 object = find_and_get_object(ptr, 0); 649 if (!object) { 650 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); 651 return; 652 } 653 654 spin_lock_irqsave(&object->lock, flags); 655 object->flags |= OBJECT_NO_SCAN; 656 spin_unlock_irqrestore(&object->lock, flags); 657 put_object(object); 658} 659 660/* 661 * Log an early kmemleak_* call to the early_log buffer. These calls will be 662 * processed later once kmemleak is fully initialized. 663 */ 664static void log_early(int op_type, const void *ptr, size_t size, 665 int min_count, unsigned long offset, size_t length) 666{ 667 unsigned long flags; 668 struct early_log *log; 669 670 if (crt_early_log >= ARRAY_SIZE(early_log)) { 671 pr_warning("Early log buffer exceeded\n"); 672 kmemleak_disable(); 673 return; 674 } 675 676 /* 677 * There is no need for locking since the kernel is still in UP mode 678 * at this stage. Disabling the IRQs is enough. 679 */ 680 local_irq_save(flags); 681 log = &early_log[crt_early_log]; 682 log->op_type = op_type; 683 log->ptr = ptr; 684 log->size = size; 685 log->min_count = min_count; 686 log->offset = offset; 687 log->length = length; 688 crt_early_log++; 689 local_irq_restore(flags); 690} 691 692/* 693 * Memory allocation function callback. This function is called from the 694 * kernel allocators when a new block is allocated (kmem_cache_alloc, kmalloc, 695 * vmalloc etc.). 696 */ 697void kmemleak_alloc(const void *ptr, size_t size, int min_count, gfp_t gfp) 698{ 699 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count); 700 701 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 702 create_object((unsigned long)ptr, size, min_count, gfp); 703 else if (atomic_read(&kmemleak_early_log)) 704 log_early(KMEMLEAK_ALLOC, ptr, size, min_count, 0, 0); 705} 706EXPORT_SYMBOL_GPL(kmemleak_alloc); 707 708/* 709 * Memory freeing function callback. This function is called from the kernel 710 * allocators when a block is freed (kmem_cache_free, kfree, vfree etc.). 711 */ 712void kmemleak_free(const void *ptr) 713{ 714 pr_debug("%s(0x%p)\n", __func__, ptr); 715 716 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 717 delete_object((unsigned long)ptr); 718 else if (atomic_read(&kmemleak_early_log)) 719 log_early(KMEMLEAK_FREE, ptr, 0, 0, 0, 0); 720} 721EXPORT_SYMBOL_GPL(kmemleak_free); 722 723/* 724 * Mark an already allocated memory block as a false positive. This will cause 725 * the block to no longer be reported as leak and always be scanned. 726 */ 727void kmemleak_not_leak(const void *ptr) 728{ 729 pr_debug("%s(0x%p)\n", __func__, ptr); 730 731 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 732 make_gray_object((unsigned long)ptr); 733 else if (atomic_read(&kmemleak_early_log)) 734 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0, 0, 0); 735} 736EXPORT_SYMBOL(kmemleak_not_leak); 737 738/* 739 * Ignore a memory block. This is usually done when it is known that the 740 * corresponding block is not a leak and does not contain any references to 741 * other allocated memory blocks. 742 */ 743void kmemleak_ignore(const void *ptr) 744{ 745 pr_debug("%s(0x%p)\n", __func__, ptr); 746 747 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 748 make_black_object((unsigned long)ptr); 749 else if (atomic_read(&kmemleak_early_log)) 750 log_early(KMEMLEAK_IGNORE, ptr, 0, 0, 0, 0); 751} 752EXPORT_SYMBOL(kmemleak_ignore); 753 754/* 755 * Limit the range to be scanned in an allocated memory block. 756 */ 757void kmemleak_scan_area(const void *ptr, unsigned long offset, size_t length, 758 gfp_t gfp) 759{ 760 pr_debug("%s(0x%p)\n", __func__, ptr); 761 762 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 763 add_scan_area((unsigned long)ptr, offset, length, gfp); 764 else if (atomic_read(&kmemleak_early_log)) 765 log_early(KMEMLEAK_SCAN_AREA, ptr, 0, 0, offset, length); 766} 767EXPORT_SYMBOL(kmemleak_scan_area); 768 769/* 770 * Inform kmemleak not to scan the given memory block. 771 */ 772void kmemleak_no_scan(const void *ptr) 773{ 774 pr_debug("%s(0x%p)\n", __func__, ptr); 775 776 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 777 object_no_scan((unsigned long)ptr); 778 else if (atomic_read(&kmemleak_early_log)) 779 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0, 0, 0); 780} 781EXPORT_SYMBOL(kmemleak_no_scan); 782 783/* 784 * Yield the CPU so that other tasks get a chance to run. The yielding is 785 * rate-limited to avoid excessive number of calls to the schedule() function 786 * during memory scanning. 787 */ 788static void scan_yield(void) 789{ 790 might_sleep(); 791 792 if (time_is_before_eq_jiffies(next_scan_yield)) { 793 schedule(); 794 next_scan_yield = jiffies + jiffies_scan_yield; 795 } 796} 797 798/* 799 * Memory scanning is a long process and it needs to be interruptable. This 800 * function checks whether such interrupt condition occured. 801 */ 802static int scan_should_stop(void) 803{ 804 if (!atomic_read(&kmemleak_enabled)) 805 return 1; 806 807 /* 808 * This function may be called from either process or kthread context, 809 * hence the need to check for both stop conditions. 810 */ 811 if (current->mm) 812 return signal_pending(current); 813 else 814 return kthread_should_stop(); 815 816 return 0; 817} 818 819/* 820 * Scan a memory block (exclusive range) for valid pointers and add those 821 * found to the gray list. 822 */ 823static void scan_block(void *_start, void *_end, 824 struct kmemleak_object *scanned) 825{ 826 unsigned long *ptr; 827 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); 828 unsigned long *end = _end - (BYTES_PER_POINTER - 1); 829 830 for (ptr = start; ptr < end; ptr++) { 831 unsigned long flags; 832 unsigned long pointer = *ptr; 833 struct kmemleak_object *object; 834 835 if (scan_should_stop()) 836 break; 837 838 /* 839 * When scanning a memory block with a corresponding 840 * kmemleak_object, the CPU yielding is handled in the calling 841 * code since it holds the object->lock to avoid the block 842 * freeing. 843 */ 844 if (!scanned) 845 scan_yield(); 846 847 object = find_and_get_object(pointer, 1); 848 if (!object) 849 continue; 850 if (object == scanned) { 851 /* self referenced, ignore */ 852 put_object(object); 853 continue; 854 } 855 856 /* 857 * Avoid the lockdep recursive warning on object->lock being 858 * previously acquired in scan_object(). These locks are 859 * enclosed by scan_mutex. 860 */ 861 spin_lock_irqsave_nested(&object->lock, flags, 862 SINGLE_DEPTH_NESTING); 863 if (!color_white(object)) { 864 /* non-orphan, ignored or new */ 865 spin_unlock_irqrestore(&object->lock, flags); 866 put_object(object); 867 continue; 868 } 869 870 /* 871 * Increase the object's reference count (number of pointers 872 * to the memory block). If this count reaches the required 873 * minimum, the object's color will become gray and it will be 874 * added to the gray_list. 875 */ 876 object->count++; 877 if (color_gray(object)) 878 list_add_tail(&object->gray_list, &gray_list); 879 else 880 put_object(object); 881 spin_unlock_irqrestore(&object->lock, flags); 882 } 883} 884 885/* 886 * Scan a memory block corresponding to a kmemleak_object. A condition is 887 * that object->use_count >= 1. 888 */ 889static void scan_object(struct kmemleak_object *object) 890{ 891 struct kmemleak_scan_area *area; 892 struct hlist_node *elem; 893 unsigned long flags; 894 895 /* 896 * Once the object->lock is aquired, the corresponding memory block 897 * cannot be freed (the same lock is aquired in delete_object). 898 */ 899 spin_lock_irqsave(&object->lock, flags); 900 if (object->flags & OBJECT_NO_SCAN) 901 goto out; 902 if (!(object->flags & OBJECT_ALLOCATED)) 903 /* already freed object */ 904 goto out; 905 if (hlist_empty(&object->area_list)) 906 scan_block((void *)object->pointer, 907 (void *)(object->pointer + object->size), object); 908 else 909 hlist_for_each_entry(area, elem, &object->area_list, node) 910 scan_block((void *)(object->pointer + area->offset), 911 (void *)(object->pointer + area->offset 912 + area->length), object); 913out: 914 spin_unlock_irqrestore(&object->lock, flags); 915} 916 917/* 918 * Scan data sections and all the referenced memory blocks allocated via the 919 * kernel's standard allocators. This function must be called with the 920 * scan_mutex held. 921 */ 922static void kmemleak_scan(void) 923{ 924 unsigned long flags; 925 struct kmemleak_object *object, *tmp; 926 struct task_struct *task; 927 int i; 928 int new_leaks = 0; 929 930 /* prepare the kmemleak_object's */ 931 rcu_read_lock(); 932 list_for_each_entry_rcu(object, &object_list, object_list) { 933 spin_lock_irqsave(&object->lock, flags); 934#ifdef DEBUG 935 /* 936 * With a few exceptions there should be a maximum of 937 * 1 reference to any object at this point. 938 */ 939 if (atomic_read(&object->use_count) > 1) { 940 pr_debug("object->use_count = %d\n", 941 atomic_read(&object->use_count)); 942 dump_object_info(object); 943 } 944#endif 945 /* reset the reference count (whiten the object) */ 946 object->count = 0; 947 if (color_gray(object) && get_object(object)) 948 list_add_tail(&object->gray_list, &gray_list); 949 950 spin_unlock_irqrestore(&object->lock, flags); 951 } 952 rcu_read_unlock(); 953 954 /* data/bss scanning */ 955 scan_block(_sdata, _edata, NULL); 956 scan_block(__bss_start, __bss_stop, NULL); 957 958#ifdef CONFIG_SMP 959 /* per-cpu sections scanning */ 960 for_each_possible_cpu(i) 961 scan_block(__per_cpu_start + per_cpu_offset(i), 962 __per_cpu_end + per_cpu_offset(i), NULL); 963#endif 964 965 /* 966 * Struct page scanning for each node. The code below is not yet safe 967 * with MEMORY_HOTPLUG. 968 */ 969 for_each_online_node(i) { 970 pg_data_t *pgdat = NODE_DATA(i); 971 unsigned long start_pfn = pgdat->node_start_pfn; 972 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages; 973 unsigned long pfn; 974 975 for (pfn = start_pfn; pfn < end_pfn; pfn++) { 976 struct page *page; 977 978 if (!pfn_valid(pfn)) 979 continue; 980 page = pfn_to_page(pfn); 981 /* only scan if page is in use */ 982 if (page_count(page) == 0) 983 continue; 984 scan_block(page, page + 1, NULL); 985 } 986 } 987 988 /* 989 * Scanning the task stacks may introduce false negatives and it is 990 * not enabled by default. 991 */ 992 if (kmemleak_stack_scan) { 993 read_lock(&tasklist_lock); 994 for_each_process(task) 995 scan_block(task_stack_page(task), 996 task_stack_page(task) + THREAD_SIZE, NULL); 997 read_unlock(&tasklist_lock); 998 } 999 1000 /* 1001 * Scan the objects already referenced from the sections scanned 1002 * above. More objects will be referenced and, if there are no memory 1003 * leaks, all the objects will be scanned. The list traversal is safe 1004 * for both tail additions and removals from inside the loop. The 1005 * kmemleak objects cannot be freed from outside the loop because their 1006 * use_count was increased. 1007 */ 1008 object = list_entry(gray_list.next, typeof(*object), gray_list); 1009 while (&object->gray_list != &gray_list) { 1010 scan_yield(); 1011 1012 /* may add new objects to the list */ 1013 if (!scan_should_stop()) 1014 scan_object(object); 1015 1016 tmp = list_entry(object->gray_list.next, typeof(*object), 1017 gray_list); 1018 1019 /* remove the object from the list and release it */ 1020 list_del(&object->gray_list); 1021 put_object(object); 1022 1023 object = tmp; 1024 } 1025 WARN_ON(!list_empty(&gray_list)); 1026 1027 /* 1028 * Scanning result reporting. 1029 */ 1030 rcu_read_lock(); 1031 list_for_each_entry_rcu(object, &object_list, object_list) { 1032 spin_lock_irqsave(&object->lock, flags); 1033 if (unreferenced_object(object) && 1034 !(object->flags & OBJECT_REPORTED)) { 1035 object->flags |= OBJECT_REPORTED; 1036 new_leaks++; 1037 } 1038 spin_unlock_irqrestore(&object->lock, flags); 1039 } 1040 rcu_read_unlock(); 1041 1042 if (new_leaks) 1043 pr_info("%d new suspected memory leaks (see " 1044 "/sys/kernel/debug/kmemleak)\n", new_leaks); 1045 1046} 1047 1048/* 1049 * Thread function performing automatic memory scanning. Unreferenced objects 1050 * at the end of a memory scan are reported but only the first time. 1051 */ 1052static int kmemleak_scan_thread(void *arg) 1053{ 1054 static int first_run = 1; 1055 1056 pr_info("Automatic memory scanning thread started\n"); 1057 1058 /* 1059 * Wait before the first scan to allow the system to fully initialize. 1060 */ 1061 if (first_run) { 1062 first_run = 0; 1063 ssleep(SECS_FIRST_SCAN); 1064 } 1065 1066 while (!kthread_should_stop()) { 1067 signed long timeout = jiffies_scan_wait; 1068 1069 mutex_lock(&scan_mutex); 1070 kmemleak_scan(); 1071 mutex_unlock(&scan_mutex); 1072 1073 /* wait before the next scan */ 1074 while (timeout && !kthread_should_stop()) 1075 timeout = schedule_timeout_interruptible(timeout); 1076 } 1077 1078 pr_info("Automatic memory scanning thread ended\n"); 1079 1080 return 0; 1081} 1082 1083/* 1084 * Start the automatic memory scanning thread. This function must be called 1085 * with the scan_mutex held. 1086 */ 1087void start_scan_thread(void) 1088{ 1089 if (scan_thread) 1090 return; 1091 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); 1092 if (IS_ERR(scan_thread)) { 1093 pr_warning("Failed to create the scan thread\n"); 1094 scan_thread = NULL; 1095 } 1096} 1097 1098/* 1099 * Stop the automatic memory scanning thread. This function must be called 1100 * with the scan_mutex held. 1101 */ 1102void stop_scan_thread(void) 1103{ 1104 if (scan_thread) { 1105 kthread_stop(scan_thread); 1106 scan_thread = NULL; 1107 } 1108} 1109 1110/* 1111 * Iterate over the object_list and return the first valid object at or after 1112 * the required position with its use_count incremented. The function triggers 1113 * a memory scanning when the pos argument points to the first position. 1114 */ 1115static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) 1116{ 1117 struct kmemleak_object *object; 1118 loff_t n = *pos; 1119 1120 if (!n) 1121 reported_leaks = 0; 1122 if (reported_leaks >= REPORTS_NR) 1123 return NULL; 1124 1125 rcu_read_lock(); 1126 list_for_each_entry_rcu(object, &object_list, object_list) { 1127 if (n-- > 0) 1128 continue; 1129 if (get_object(object)) 1130 goto out; 1131 } 1132 object = NULL; 1133out: 1134 rcu_read_unlock(); 1135 return object; 1136} 1137 1138/* 1139 * Return the next object in the object_list. The function decrements the 1140 * use_count of the previous object and increases that of the next one. 1141 */ 1142static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1143{ 1144 struct kmemleak_object *prev_obj = v; 1145 struct kmemleak_object *next_obj = NULL; 1146 struct list_head *n = &prev_obj->object_list; 1147 1148 ++(*pos); 1149 if (reported_leaks >= REPORTS_NR) 1150 goto out; 1151 1152 rcu_read_lock(); 1153 list_for_each_continue_rcu(n, &object_list) { 1154 next_obj = list_entry(n, struct kmemleak_object, object_list); 1155 if (get_object(next_obj)) 1156 break; 1157 } 1158 rcu_read_unlock(); 1159out: 1160 put_object(prev_obj); 1161 return next_obj; 1162} 1163 1164/* 1165 * Decrement the use_count of the last object required, if any. 1166 */ 1167static void kmemleak_seq_stop(struct seq_file *seq, void *v) 1168{ 1169 if (v) 1170 put_object(v); 1171} 1172 1173/* 1174 * Print the information for an unreferenced object to the seq file. 1175 */ 1176static int kmemleak_seq_show(struct seq_file *seq, void *v) 1177{ 1178 struct kmemleak_object *object = v; 1179 unsigned long flags; 1180 1181 spin_lock_irqsave(&object->lock, flags); 1182 if (!unreferenced_object(object)) 1183 goto out; 1184 print_unreferenced(seq, object); 1185 reported_leaks++; 1186out: 1187 spin_unlock_irqrestore(&object->lock, flags); 1188 return 0; 1189} 1190 1191static const struct seq_operations kmemleak_seq_ops = { 1192 .start = kmemleak_seq_start, 1193 .next = kmemleak_seq_next, 1194 .stop = kmemleak_seq_stop, 1195 .show = kmemleak_seq_show, 1196}; 1197 1198static int kmemleak_open(struct inode *inode, struct file *file) 1199{ 1200 int ret = 0; 1201 1202 if (!atomic_read(&kmemleak_enabled)) 1203 return -EBUSY; 1204 1205 ret = mutex_lock_interruptible(&scan_mutex); 1206 if (ret < 0) 1207 goto out; 1208 if (file->f_mode & FMODE_READ) { 1209 ret = seq_open(file, &kmemleak_seq_ops); 1210 if (ret < 0) 1211 goto scan_unlock; 1212 } 1213 return ret; 1214 1215scan_unlock: 1216 mutex_unlock(&scan_mutex); 1217out: 1218 return ret; 1219} 1220 1221static int kmemleak_release(struct inode *inode, struct file *file) 1222{ 1223 int ret = 0; 1224 1225 if (file->f_mode & FMODE_READ) 1226 seq_release(inode, file); 1227 mutex_unlock(&scan_mutex); 1228 1229 return ret; 1230} 1231 1232/* 1233 * File write operation to configure kmemleak at run-time. The following 1234 * commands can be written to the /sys/kernel/debug/kmemleak file: 1235 * off - disable kmemleak (irreversible) 1236 * stack=on - enable the task stacks scanning 1237 * stack=off - disable the tasks stacks scanning 1238 * scan=on - start the automatic memory scanning thread 1239 * scan=off - stop the automatic memory scanning thread 1240 * scan=... - set the automatic memory scanning period in seconds (0 to 1241 * disable it) 1242 * scan - trigger a memory scan 1243 */ 1244static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, 1245 size_t size, loff_t *ppos) 1246{ 1247 char buf[64]; 1248 int buf_size; 1249 1250 if (!atomic_read(&kmemleak_enabled)) 1251 return -EBUSY; 1252 1253 buf_size = min(size, (sizeof(buf) - 1)); 1254 if (strncpy_from_user(buf, user_buf, buf_size) < 0) 1255 return -EFAULT; 1256 buf[buf_size] = 0; 1257 1258 if (strncmp(buf, "off", 3) == 0) 1259 kmemleak_disable(); 1260 else if (strncmp(buf, "stack=on", 8) == 0) 1261 kmemleak_stack_scan = 1; 1262 else if (strncmp(buf, "stack=off", 9) == 0) 1263 kmemleak_stack_scan = 0; 1264 else if (strncmp(buf, "scan=on", 7) == 0) 1265 start_scan_thread(); 1266 else if (strncmp(buf, "scan=off", 8) == 0) 1267 stop_scan_thread(); 1268 else if (strncmp(buf, "scan=", 5) == 0) { 1269 unsigned long secs; 1270 int err; 1271 1272 err = strict_strtoul(buf + 5, 0, &secs); 1273 if (err < 0) 1274 return err; 1275 stop_scan_thread(); 1276 if (secs) { 1277 jiffies_scan_wait = msecs_to_jiffies(secs * 1000); 1278 start_scan_thread(); 1279 } 1280 } else if (strncmp(buf, "scan", 4) == 0) 1281 kmemleak_scan(); 1282 else 1283 return -EINVAL; 1284 1285 /* ignore the rest of the buffer, only one command at a time */ 1286 *ppos += size; 1287 return size; 1288} 1289 1290static const struct file_operations kmemleak_fops = { 1291 .owner = THIS_MODULE, 1292 .open = kmemleak_open, 1293 .read = seq_read, 1294 .write = kmemleak_write, 1295 .llseek = seq_lseek, 1296 .release = kmemleak_release, 1297}; 1298 1299/* 1300 * Perform the freeing of the kmemleak internal objects after waiting for any 1301 * current memory scan to complete. 1302 */ 1303static int kmemleak_cleanup_thread(void *arg) 1304{ 1305 struct kmemleak_object *object; 1306 1307 mutex_lock(&scan_mutex); 1308 stop_scan_thread(); 1309 1310 rcu_read_lock(); 1311 list_for_each_entry_rcu(object, &object_list, object_list) 1312 delete_object(object->pointer); 1313 rcu_read_unlock(); 1314 mutex_unlock(&scan_mutex); 1315 1316 return 0; 1317} 1318 1319/* 1320 * Start the clean-up thread. 1321 */ 1322static void kmemleak_cleanup(void) 1323{ 1324 struct task_struct *cleanup_thread; 1325 1326 cleanup_thread = kthread_run(kmemleak_cleanup_thread, NULL, 1327 "kmemleak-clean"); 1328 if (IS_ERR(cleanup_thread)) 1329 pr_warning("Failed to create the clean-up thread\n"); 1330} 1331 1332/* 1333 * Disable kmemleak. No memory allocation/freeing will be traced once this 1334 * function is called. Disabling kmemleak is an irreversible operation. 1335 */ 1336static void kmemleak_disable(void) 1337{ 1338 /* atomically check whether it was already invoked */ 1339 if (atomic_cmpxchg(&kmemleak_error, 0, 1)) 1340 return; 1341 1342 /* stop any memory operation tracing */ 1343 atomic_set(&kmemleak_early_log, 0); 1344 atomic_set(&kmemleak_enabled, 0); 1345 1346 /* check whether it is too early for a kernel thread */ 1347 if (atomic_read(&kmemleak_initialized)) 1348 kmemleak_cleanup(); 1349 1350 pr_info("Kernel memory leak detector disabled\n"); 1351} 1352 1353/* 1354 * Allow boot-time kmemleak disabling (enabled by default). 1355 */ 1356static int kmemleak_boot_config(char *str) 1357{ 1358 if (!str) 1359 return -EINVAL; 1360 if (strcmp(str, "off") == 0) 1361 kmemleak_disable(); 1362 else if (strcmp(str, "on") != 0) 1363 return -EINVAL; 1364 return 0; 1365} 1366early_param("kmemleak", kmemleak_boot_config); 1367 1368/* 1369 * Kmemleak initialization. 1370 */ 1371void __init kmemleak_init(void) 1372{ 1373 int i; 1374 unsigned long flags; 1375 1376 jiffies_scan_yield = msecs_to_jiffies(MSECS_SCAN_YIELD); 1377 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); 1378 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); 1379 1380 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); 1381 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); 1382 INIT_PRIO_TREE_ROOT(&object_tree_root); 1383 1384 /* the kernel is still in UP mode, so disabling the IRQs is enough */ 1385 local_irq_save(flags); 1386 if (!atomic_read(&kmemleak_error)) { 1387 atomic_set(&kmemleak_enabled, 1); 1388 atomic_set(&kmemleak_early_log, 0); 1389 } 1390 local_irq_restore(flags); 1391 1392 /* 1393 * This is the point where tracking allocations is safe. Automatic 1394 * scanning is started during the late initcall. Add the early logged 1395 * callbacks to the kmemleak infrastructure. 1396 */ 1397 for (i = 0; i < crt_early_log; i++) { 1398 struct early_log *log = &early_log[i]; 1399 1400 switch (log->op_type) { 1401 case KMEMLEAK_ALLOC: 1402 kmemleak_alloc(log->ptr, log->size, log->min_count, 1403 GFP_KERNEL); 1404 break; 1405 case KMEMLEAK_FREE: 1406 kmemleak_free(log->ptr); 1407 break; 1408 case KMEMLEAK_NOT_LEAK: 1409 kmemleak_not_leak(log->ptr); 1410 break; 1411 case KMEMLEAK_IGNORE: 1412 kmemleak_ignore(log->ptr); 1413 break; 1414 case KMEMLEAK_SCAN_AREA: 1415 kmemleak_scan_area(log->ptr, log->offset, log->length, 1416 GFP_KERNEL); 1417 break; 1418 case KMEMLEAK_NO_SCAN: 1419 kmemleak_no_scan(log->ptr); 1420 break; 1421 default: 1422 WARN_ON(1); 1423 } 1424 } 1425} 1426 1427/* 1428 * Late initialization function. 1429 */ 1430static int __init kmemleak_late_init(void) 1431{ 1432 struct dentry *dentry; 1433 1434 atomic_set(&kmemleak_initialized, 1); 1435 1436 if (atomic_read(&kmemleak_error)) { 1437 /* 1438 * Some error occured and kmemleak was disabled. There is a 1439 * small chance that kmemleak_disable() was called immediately 1440 * after setting kmemleak_initialized and we may end up with 1441 * two clean-up threads but serialized by scan_mutex. 1442 */ 1443 kmemleak_cleanup(); 1444 return -ENOMEM; 1445 } 1446 1447 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL, 1448 &kmemleak_fops); 1449 if (!dentry) 1450 pr_warning("Failed to create the debugfs kmemleak file\n"); 1451 mutex_lock(&scan_mutex); 1452 start_scan_thread(); 1453 mutex_unlock(&scan_mutex); 1454 1455 pr_info("Kernel memory leak detector initialized\n"); 1456 1457 return 0; 1458} 1459late_initcall(kmemleak_late_init); 1460