kmemleak.c revision b6e687221eb840bacd4d4a991e5f8e7ed3ae910a
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; 193/* used to avoid reporting of recently allocated objects */ 194static unsigned long jiffies_min_age; 195static unsigned long jiffies_last_scan; 196/* delay between automatic memory scannings */ 197static signed long jiffies_scan_wait; 198/* enables or disables the task stacks scanning */ 199static int kmemleak_stack_scan = 1; 200/* protects the memory scanning, parameters and debug/kmemleak file access */ 201static DEFINE_MUTEX(scan_mutex); 202 203/* number of leaks reported (for limitation purposes) */ 204static int reported_leaks; 205 206/* 207 * Early object allocation/freeing logging. Kmemleak is initialized after the 208 * kernel allocator. However, both the kernel allocator and kmemleak may 209 * allocate memory blocks which need to be tracked. Kmemleak defines an 210 * arbitrary buffer to hold the allocation/freeing information before it is 211 * fully initialized. 212 */ 213 214/* kmemleak operation type for early logging */ 215enum { 216 KMEMLEAK_ALLOC, 217 KMEMLEAK_FREE, 218 KMEMLEAK_NOT_LEAK, 219 KMEMLEAK_IGNORE, 220 KMEMLEAK_SCAN_AREA, 221 KMEMLEAK_NO_SCAN 222}; 223 224/* 225 * Structure holding the information passed to kmemleak callbacks during the 226 * early logging. 227 */ 228struct early_log { 229 int op_type; /* kmemleak operation type */ 230 const void *ptr; /* allocated/freed memory block */ 231 size_t size; /* memory block size */ 232 int min_count; /* minimum reference count */ 233 unsigned long offset; /* scan area offset */ 234 size_t length; /* scan area length */ 235}; 236 237/* early logging buffer and current position */ 238static struct early_log early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE]; 239static int crt_early_log; 240 241static 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 253 * recovered from. Kmemleak will be disabled and further allocation/freeing 254 * tracing no longer available. 255 */ 256#define kmemleak_stop(x...) do { \ 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 */ 271static int color_white(const struct kmemleak_object *object) 272{ 273 return object->count != -1 && object->count < object->min_count; 274} 275 276static int color_gray(const struct kmemleak_object *object) 277{ 278 return object->min_count != -1 && object->count >= object->min_count; 279} 280 281/* 282 * Objects are considered unreferenced only if their color is white, they have 283 * not be deleted and have a minimum age to avoid false positives caused by 284 * pointers temporarily stored in CPU registers. 285 */ 286static int unreferenced_object(struct kmemleak_object *object) 287{ 288 return (object->flags & OBJECT_ALLOCATED) && color_white(object) && 289 time_before_eq(object->jiffies + jiffies_min_age, 290 jiffies_last_scan); 291} 292 293/* 294 * Printing of the unreferenced objects information to the seq file. The 295 * print_unreferenced function must be called with the object->lock held. 296 */ 297static void print_unreferenced(struct seq_file *seq, 298 struct kmemleak_object *object) 299{ 300 int i; 301 302 seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", 303 object->pointer, object->size); 304 seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", 305 object->comm, object->pid, object->jiffies); 306 seq_printf(seq, " backtrace:\n"); 307 308 for (i = 0; i < object->trace_len; i++) { 309 void *ptr = (void *)object->trace[i]; 310 seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); 311 } 312} 313 314/* 315 * Print the kmemleak_object information. This function is used mainly for 316 * debugging special cases when kmemleak operations. It must be called with 317 * the object->lock held. 318 */ 319static void dump_object_info(struct kmemleak_object *object) 320{ 321 struct stack_trace trace; 322 323 trace.nr_entries = object->trace_len; 324 trace.entries = object->trace; 325 326 pr_notice("Object 0x%08lx (size %zu):\n", 327 object->tree_node.start, object->size); 328 pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", 329 object->comm, object->pid, object->jiffies); 330 pr_notice(" min_count = %d\n", object->min_count); 331 pr_notice(" count = %d\n", object->count); 332 pr_notice(" backtrace:\n"); 333 print_stack_trace(&trace, 4); 334} 335 336/* 337 * Look-up a memory block metadata (kmemleak_object) in the priority search 338 * tree based on a pointer value. If alias is 0, only values pointing to the 339 * beginning of the memory block are allowed. The kmemleak_lock must be held 340 * when calling this function. 341 */ 342static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) 343{ 344 struct prio_tree_node *node; 345 struct prio_tree_iter iter; 346 struct kmemleak_object *object; 347 348 prio_tree_iter_init(&iter, &object_tree_root, ptr, ptr); 349 node = prio_tree_next(&iter); 350 if (node) { 351 object = prio_tree_entry(node, struct kmemleak_object, 352 tree_node); 353 if (!alias && object->pointer != ptr) { 354 kmemleak_warn("Found object by alias"); 355 object = NULL; 356 } 357 } else 358 object = NULL; 359 360 return object; 361} 362 363/* 364 * Increment the object use_count. Return 1 if successful or 0 otherwise. Note 365 * that once an object's use_count reached 0, the RCU freeing was already 366 * registered and the object should no longer be used. This function must be 367 * called under the protection of rcu_read_lock(). 368 */ 369static int get_object(struct kmemleak_object *object) 370{ 371 return atomic_inc_not_zero(&object->use_count); 372} 373 374/* 375 * RCU callback to free a kmemleak_object. 376 */ 377static void free_object_rcu(struct rcu_head *rcu) 378{ 379 struct hlist_node *elem, *tmp; 380 struct kmemleak_scan_area *area; 381 struct kmemleak_object *object = 382 container_of(rcu, struct kmemleak_object, rcu); 383 384 /* 385 * Once use_count is 0 (guaranteed by put_object), there is no other 386 * code accessing this object, hence no need for locking. 387 */ 388 hlist_for_each_entry_safe(area, elem, tmp, &object->area_list, node) { 389 hlist_del(elem); 390 kmem_cache_free(scan_area_cache, area); 391 } 392 kmem_cache_free(object_cache, object); 393} 394 395/* 396 * Decrement the object use_count. Once the count is 0, free the object using 397 * an RCU callback. Since put_object() may be called via the kmemleak_free() -> 398 * delete_object() path, the delayed RCU freeing ensures that there is no 399 * recursive call to the kernel allocator. Lock-less RCU object_list traversal 400 * is also possible. 401 */ 402static void put_object(struct kmemleak_object *object) 403{ 404 if (!atomic_dec_and_test(&object->use_count)) 405 return; 406 407 /* should only get here after delete_object was called */ 408 WARN_ON(object->flags & OBJECT_ALLOCATED); 409 410 call_rcu(&object->rcu, free_object_rcu); 411} 412 413/* 414 * Look up an object in the prio search tree and increase its use_count. 415 */ 416static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) 417{ 418 unsigned long flags; 419 struct kmemleak_object *object = NULL; 420 421 rcu_read_lock(); 422 read_lock_irqsave(&kmemleak_lock, flags); 423 if (ptr >= min_addr && ptr < max_addr) 424 object = lookup_object(ptr, alias); 425 read_unlock_irqrestore(&kmemleak_lock, flags); 426 427 /* check whether the object is still available */ 428 if (object && !get_object(object)) 429 object = NULL; 430 rcu_read_unlock(); 431 432 return object; 433} 434 435/* 436 * Create the metadata (struct kmemleak_object) corresponding to an allocated 437 * memory block and add it to the object_list and object_tree_root. 438 */ 439static void create_object(unsigned long ptr, size_t size, int min_count, 440 gfp_t gfp) 441{ 442 unsigned long flags; 443 struct kmemleak_object *object; 444 struct prio_tree_node *node; 445 struct stack_trace trace; 446 447 object = kmem_cache_alloc(object_cache, gfp & GFP_KMEMLEAK_MASK); 448 if (!object) { 449 kmemleak_stop("Cannot allocate a kmemleak_object structure\n"); 450 return; 451 } 452 453 INIT_LIST_HEAD(&object->object_list); 454 INIT_LIST_HEAD(&object->gray_list); 455 INIT_HLIST_HEAD(&object->area_list); 456 spin_lock_init(&object->lock); 457 atomic_set(&object->use_count, 1); 458 object->flags = OBJECT_ALLOCATED; 459 object->pointer = ptr; 460 object->size = size; 461 object->min_count = min_count; 462 object->count = -1; /* no color initially */ 463 object->jiffies = jiffies; 464 465 /* task information */ 466 if (in_irq()) { 467 object->pid = 0; 468 strncpy(object->comm, "hardirq", sizeof(object->comm)); 469 } else if (in_softirq()) { 470 object->pid = 0; 471 strncpy(object->comm, "softirq", sizeof(object->comm)); 472 } else { 473 object->pid = current->pid; 474 /* 475 * There is a small chance of a race with set_task_comm(), 476 * however using get_task_comm() here may cause locking 477 * dependency issues with current->alloc_lock. In the worst 478 * case, the command line is not correct. 479 */ 480 strncpy(object->comm, current->comm, sizeof(object->comm)); 481 } 482 483 /* kernel backtrace */ 484 trace.max_entries = MAX_TRACE; 485 trace.nr_entries = 0; 486 trace.entries = object->trace; 487 trace.skip = 1; 488 save_stack_trace(&trace); 489 object->trace_len = trace.nr_entries; 490 491 INIT_PRIO_TREE_NODE(&object->tree_node); 492 object->tree_node.start = ptr; 493 object->tree_node.last = ptr + size - 1; 494 495 write_lock_irqsave(&kmemleak_lock, flags); 496 min_addr = min(min_addr, ptr); 497 max_addr = max(max_addr, ptr + size); 498 node = prio_tree_insert(&object_tree_root, &object->tree_node); 499 /* 500 * The code calling the kernel does not yet have the pointer to the 501 * memory block to be able to free it. However, we still hold the 502 * kmemleak_lock here in case parts of the kernel started freeing 503 * random memory blocks. 504 */ 505 if (node != &object->tree_node) { 506 unsigned long flags; 507 508 kmemleak_stop("Cannot insert 0x%lx into the object search tree " 509 "(already existing)\n", ptr); 510 object = lookup_object(ptr, 1); 511 spin_lock_irqsave(&object->lock, flags); 512 dump_object_info(object); 513 spin_unlock_irqrestore(&object->lock, flags); 514 515 goto out; 516 } 517 list_add_tail_rcu(&object->object_list, &object_list); 518out: 519 write_unlock_irqrestore(&kmemleak_lock, flags); 520} 521 522/* 523 * Remove the metadata (struct kmemleak_object) for a memory block from the 524 * object_list and object_tree_root and decrement its use_count. 525 */ 526static void delete_object(unsigned long ptr) 527{ 528 unsigned long flags; 529 struct kmemleak_object *object; 530 531 write_lock_irqsave(&kmemleak_lock, flags); 532 object = lookup_object(ptr, 0); 533 if (!object) { 534#ifdef DEBUG 535 kmemleak_warn("Freeing unknown object at 0x%08lx\n", 536 ptr); 537#endif 538 write_unlock_irqrestore(&kmemleak_lock, flags); 539 return; 540 } 541 prio_tree_remove(&object_tree_root, &object->tree_node); 542 list_del_rcu(&object->object_list); 543 write_unlock_irqrestore(&kmemleak_lock, flags); 544 545 WARN_ON(!(object->flags & OBJECT_ALLOCATED)); 546 WARN_ON(atomic_read(&object->use_count) < 1); 547 548 /* 549 * Locking here also ensures that the corresponding memory block 550 * cannot be freed when it is being scanned. 551 */ 552 spin_lock_irqsave(&object->lock, flags); 553 object->flags &= ~OBJECT_ALLOCATED; 554 spin_unlock_irqrestore(&object->lock, flags); 555 put_object(object); 556} 557 558/* 559 * Make a object permanently as gray-colored so that it can no longer be 560 * reported as a leak. This is used in general to mark a false positive. 561 */ 562static void make_gray_object(unsigned long ptr) 563{ 564 unsigned long flags; 565 struct kmemleak_object *object; 566 567 object = find_and_get_object(ptr, 0); 568 if (!object) { 569 kmemleak_warn("Graying unknown object at 0x%08lx\n", ptr); 570 return; 571 } 572 573 spin_lock_irqsave(&object->lock, flags); 574 object->min_count = 0; 575 spin_unlock_irqrestore(&object->lock, flags); 576 put_object(object); 577} 578 579/* 580 * Mark the object as black-colored so that it is ignored from scans and 581 * reporting. 582 */ 583static void make_black_object(unsigned long ptr) 584{ 585 unsigned long flags; 586 struct kmemleak_object *object; 587 588 object = find_and_get_object(ptr, 0); 589 if (!object) { 590 kmemleak_warn("Blacking unknown object at 0x%08lx\n", ptr); 591 return; 592 } 593 594 spin_lock_irqsave(&object->lock, flags); 595 object->min_count = -1; 596 spin_unlock_irqrestore(&object->lock, flags); 597 put_object(object); 598} 599 600/* 601 * Add a scanning area to the object. If at least one such area is added, 602 * kmemleak will only scan these ranges rather than the whole memory block. 603 */ 604static void add_scan_area(unsigned long ptr, unsigned long offset, 605 size_t length, gfp_t gfp) 606{ 607 unsigned long flags; 608 struct kmemleak_object *object; 609 struct kmemleak_scan_area *area; 610 611 object = find_and_get_object(ptr, 0); 612 if (!object) { 613 kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n", 614 ptr); 615 return; 616 } 617 618 area = kmem_cache_alloc(scan_area_cache, gfp & GFP_KMEMLEAK_MASK); 619 if (!area) { 620 kmemleak_warn("Cannot allocate a scan area\n"); 621 goto out; 622 } 623 624 spin_lock_irqsave(&object->lock, flags); 625 if (offset + length > object->size) { 626 kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); 627 dump_object_info(object); 628 kmem_cache_free(scan_area_cache, area); 629 goto out_unlock; 630 } 631 632 INIT_HLIST_NODE(&area->node); 633 area->offset = offset; 634 area->length = length; 635 636 hlist_add_head(&area->node, &object->area_list); 637out_unlock: 638 spin_unlock_irqrestore(&object->lock, flags); 639out: 640 put_object(object); 641} 642 643/* 644 * Set the OBJECT_NO_SCAN flag for the object corresponding to the give 645 * pointer. Such object will not be scanned by kmemleak but references to it 646 * are searched. 647 */ 648static void object_no_scan(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) { 655 kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr); 656 return; 657 } 658 659 spin_lock_irqsave(&object->lock, flags); 660 object->flags |= OBJECT_NO_SCAN; 661 spin_unlock_irqrestore(&object->lock, flags); 662 put_object(object); 663} 664 665/* 666 * Log an early kmemleak_* call to the early_log buffer. These calls will be 667 * processed later once kmemleak is fully initialized. 668 */ 669static void log_early(int op_type, const void *ptr, size_t size, 670 int min_count, unsigned long offset, size_t length) 671{ 672 unsigned long flags; 673 struct early_log *log; 674 675 if (crt_early_log >= ARRAY_SIZE(early_log)) { 676 pr_warning("Early log buffer exceeded\n"); 677 kmemleak_disable(); 678 return; 679 } 680 681 /* 682 * There is no need for locking since the kernel is still in UP mode 683 * at this stage. Disabling the IRQs is enough. 684 */ 685 local_irq_save(flags); 686 log = &early_log[crt_early_log]; 687 log->op_type = op_type; 688 log->ptr = ptr; 689 log->size = size; 690 log->min_count = min_count; 691 log->offset = offset; 692 log->length = length; 693 crt_early_log++; 694 local_irq_restore(flags); 695} 696 697/* 698 * Memory allocation function callback. This function is called from the 699 * kernel allocators when a new block is allocated (kmem_cache_alloc, kmalloc, 700 * vmalloc etc.). 701 */ 702void kmemleak_alloc(const void *ptr, size_t size, int min_count, gfp_t gfp) 703{ 704 pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count); 705 706 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 707 create_object((unsigned long)ptr, size, min_count, gfp); 708 else if (atomic_read(&kmemleak_early_log)) 709 log_early(KMEMLEAK_ALLOC, ptr, size, min_count, 0, 0); 710} 711EXPORT_SYMBOL_GPL(kmemleak_alloc); 712 713/* 714 * Memory freeing function callback. This function is called from the kernel 715 * allocators when a block is freed (kmem_cache_free, kfree, vfree etc.). 716 */ 717void kmemleak_free(const void *ptr) 718{ 719 pr_debug("%s(0x%p)\n", __func__, ptr); 720 721 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 722 delete_object((unsigned long)ptr); 723 else if (atomic_read(&kmemleak_early_log)) 724 log_early(KMEMLEAK_FREE, ptr, 0, 0, 0, 0); 725} 726EXPORT_SYMBOL_GPL(kmemleak_free); 727 728/* 729 * Mark an already allocated memory block as a false positive. This will cause 730 * the block to no longer be reported as leak and always be scanned. 731 */ 732void kmemleak_not_leak(const void *ptr) 733{ 734 pr_debug("%s(0x%p)\n", __func__, ptr); 735 736 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 737 make_gray_object((unsigned long)ptr); 738 else if (atomic_read(&kmemleak_early_log)) 739 log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0, 0, 0); 740} 741EXPORT_SYMBOL(kmemleak_not_leak); 742 743/* 744 * Ignore a memory block. This is usually done when it is known that the 745 * corresponding block is not a leak and does not contain any references to 746 * other allocated memory blocks. 747 */ 748void kmemleak_ignore(const void *ptr) 749{ 750 pr_debug("%s(0x%p)\n", __func__, ptr); 751 752 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 753 make_black_object((unsigned long)ptr); 754 else if (atomic_read(&kmemleak_early_log)) 755 log_early(KMEMLEAK_IGNORE, ptr, 0, 0, 0, 0); 756} 757EXPORT_SYMBOL(kmemleak_ignore); 758 759/* 760 * Limit the range to be scanned in an allocated memory block. 761 */ 762void kmemleak_scan_area(const void *ptr, unsigned long offset, size_t length, 763 gfp_t gfp) 764{ 765 pr_debug("%s(0x%p)\n", __func__, ptr); 766 767 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 768 add_scan_area((unsigned long)ptr, offset, length, gfp); 769 else if (atomic_read(&kmemleak_early_log)) 770 log_early(KMEMLEAK_SCAN_AREA, ptr, 0, 0, offset, length); 771} 772EXPORT_SYMBOL(kmemleak_scan_area); 773 774/* 775 * Inform kmemleak not to scan the given memory block. 776 */ 777void kmemleak_no_scan(const void *ptr) 778{ 779 pr_debug("%s(0x%p)\n", __func__, ptr); 780 781 if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr)) 782 object_no_scan((unsigned long)ptr); 783 else if (atomic_read(&kmemleak_early_log)) 784 log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0, 0, 0); 785} 786EXPORT_SYMBOL(kmemleak_no_scan); 787 788/* 789 * Yield the CPU so that other tasks get a chance to run. The yielding is 790 * rate-limited to avoid excessive number of calls to the schedule() function 791 * during memory scanning. 792 */ 793static void scan_yield(void) 794{ 795 might_sleep(); 796 797 if (time_is_before_eq_jiffies(next_scan_yield)) { 798 schedule(); 799 next_scan_yield = jiffies + jiffies_scan_yield; 800 } 801} 802 803/* 804 * Memory scanning is a long process and it needs to be interruptable. This 805 * function checks whether such interrupt condition occured. 806 */ 807static int scan_should_stop(void) 808{ 809 if (!atomic_read(&kmemleak_enabled)) 810 return 1; 811 812 /* 813 * This function may be called from either process or kthread context, 814 * hence the need to check for both stop conditions. 815 */ 816 if (current->mm) 817 return signal_pending(current); 818 else 819 return kthread_should_stop(); 820 821 return 0; 822} 823 824/* 825 * Scan a memory block (exclusive range) for valid pointers and add those 826 * found to the gray list. 827 */ 828static void scan_block(void *_start, void *_end, 829 struct kmemleak_object *scanned) 830{ 831 unsigned long *ptr; 832 unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); 833 unsigned long *end = _end - (BYTES_PER_POINTER - 1); 834 835 for (ptr = start; ptr < end; ptr++) { 836 unsigned long flags; 837 unsigned long pointer = *ptr; 838 struct kmemleak_object *object; 839 840 if (scan_should_stop()) 841 break; 842 843 /* 844 * When scanning a memory block with a corresponding 845 * kmemleak_object, the CPU yielding is handled in the calling 846 * code since it holds the object->lock to avoid the block 847 * freeing. 848 */ 849 if (!scanned) 850 scan_yield(); 851 852 object = find_and_get_object(pointer, 1); 853 if (!object) 854 continue; 855 if (object == scanned) { 856 /* self referenced, ignore */ 857 put_object(object); 858 continue; 859 } 860 861 /* 862 * Avoid the lockdep recursive warning on object->lock being 863 * previously acquired in scan_object(). These locks are 864 * enclosed by scan_mutex. 865 */ 866 spin_lock_irqsave_nested(&object->lock, flags, 867 SINGLE_DEPTH_NESTING); 868 if (!color_white(object)) { 869 /* non-orphan, ignored or new */ 870 spin_unlock_irqrestore(&object->lock, flags); 871 put_object(object); 872 continue; 873 } 874 875 /* 876 * Increase the object's reference count (number of pointers 877 * to the memory block). If this count reaches the required 878 * minimum, the object's color will become gray and it will be 879 * added to the gray_list. 880 */ 881 object->count++; 882 if (color_gray(object)) 883 list_add_tail(&object->gray_list, &gray_list); 884 else 885 put_object(object); 886 spin_unlock_irqrestore(&object->lock, flags); 887 } 888} 889 890/* 891 * Scan a memory block corresponding to a kmemleak_object. A condition is 892 * that object->use_count >= 1. 893 */ 894static void scan_object(struct kmemleak_object *object) 895{ 896 struct kmemleak_scan_area *area; 897 struct hlist_node *elem; 898 unsigned long flags; 899 900 /* 901 * Once the object->lock is aquired, the corresponding memory block 902 * cannot be freed (the same lock is aquired in delete_object). 903 */ 904 spin_lock_irqsave(&object->lock, flags); 905 if (object->flags & OBJECT_NO_SCAN) 906 goto out; 907 if (!(object->flags & OBJECT_ALLOCATED)) 908 /* already freed object */ 909 goto out; 910 if (hlist_empty(&object->area_list)) 911 scan_block((void *)object->pointer, 912 (void *)(object->pointer + object->size), object); 913 else 914 hlist_for_each_entry(area, elem, &object->area_list, node) 915 scan_block((void *)(object->pointer + area->offset), 916 (void *)(object->pointer + area->offset 917 + area->length), object); 918out: 919 spin_unlock_irqrestore(&object->lock, flags); 920} 921 922/* 923 * Scan data sections and all the referenced memory blocks allocated via the 924 * kernel's standard allocators. This function must be called with the 925 * scan_mutex held. 926 */ 927static void kmemleak_scan(void) 928{ 929 unsigned long flags; 930 struct kmemleak_object *object, *tmp; 931 struct task_struct *task; 932 int i; 933 int new_leaks = 0; 934 935 jiffies_last_scan = jiffies; 936 937 /* prepare the kmemleak_object's */ 938 rcu_read_lock(); 939 list_for_each_entry_rcu(object, &object_list, object_list) { 940 spin_lock_irqsave(&object->lock, flags); 941#ifdef DEBUG 942 /* 943 * With a few exceptions there should be a maximum of 944 * 1 reference to any object at this point. 945 */ 946 if (atomic_read(&object->use_count) > 1) { 947 pr_debug("object->use_count = %d\n", 948 atomic_read(&object->use_count)); 949 dump_object_info(object); 950 } 951#endif 952 /* reset the reference count (whiten the object) */ 953 object->count = 0; 954 if (color_gray(object) && get_object(object)) 955 list_add_tail(&object->gray_list, &gray_list); 956 957 spin_unlock_irqrestore(&object->lock, flags); 958 } 959 rcu_read_unlock(); 960 961 /* data/bss scanning */ 962 scan_block(_sdata, _edata, NULL); 963 scan_block(__bss_start, __bss_stop, NULL); 964 965#ifdef CONFIG_SMP 966 /* per-cpu sections scanning */ 967 for_each_possible_cpu(i) 968 scan_block(__per_cpu_start + per_cpu_offset(i), 969 __per_cpu_end + per_cpu_offset(i), NULL); 970#endif 971 972 /* 973 * Struct page scanning for each node. The code below is not yet safe 974 * with MEMORY_HOTPLUG. 975 */ 976 for_each_online_node(i) { 977 pg_data_t *pgdat = NODE_DATA(i); 978 unsigned long start_pfn = pgdat->node_start_pfn; 979 unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages; 980 unsigned long pfn; 981 982 for (pfn = start_pfn; pfn < end_pfn; pfn++) { 983 struct page *page; 984 985 if (!pfn_valid(pfn)) 986 continue; 987 page = pfn_to_page(pfn); 988 /* only scan if page is in use */ 989 if (page_count(page) == 0) 990 continue; 991 scan_block(page, page + 1, NULL); 992 } 993 } 994 995 /* 996 * Scanning the task stacks may introduce false negatives and it is 997 * not enabled by default. 998 */ 999 if (kmemleak_stack_scan) { 1000 read_lock(&tasklist_lock); 1001 for_each_process(task) 1002 scan_block(task_stack_page(task), 1003 task_stack_page(task) + THREAD_SIZE, NULL); 1004 read_unlock(&tasklist_lock); 1005 } 1006 1007 /* 1008 * Scan the objects already referenced from the sections scanned 1009 * above. More objects will be referenced and, if there are no memory 1010 * leaks, all the objects will be scanned. The list traversal is safe 1011 * for both tail additions and removals from inside the loop. The 1012 * kmemleak objects cannot be freed from outside the loop because their 1013 * use_count was increased. 1014 */ 1015 object = list_entry(gray_list.next, typeof(*object), gray_list); 1016 while (&object->gray_list != &gray_list) { 1017 scan_yield(); 1018 1019 /* may add new objects to the list */ 1020 if (!scan_should_stop()) 1021 scan_object(object); 1022 1023 tmp = list_entry(object->gray_list.next, typeof(*object), 1024 gray_list); 1025 1026 /* remove the object from the list and release it */ 1027 list_del(&object->gray_list); 1028 put_object(object); 1029 1030 object = tmp; 1031 } 1032 WARN_ON(!list_empty(&gray_list)); 1033 1034 /* 1035 * If scanning was stopped do not report any new unreferenced objects. 1036 */ 1037 if (scan_should_stop()) 1038 return; 1039 1040 /* 1041 * Scanning result reporting. 1042 */ 1043 rcu_read_lock(); 1044 list_for_each_entry_rcu(object, &object_list, object_list) { 1045 spin_lock_irqsave(&object->lock, flags); 1046 if (unreferenced_object(object) && 1047 !(object->flags & OBJECT_REPORTED)) { 1048 object->flags |= OBJECT_REPORTED; 1049 new_leaks++; 1050 } 1051 spin_unlock_irqrestore(&object->lock, flags); 1052 } 1053 rcu_read_unlock(); 1054 1055 if (new_leaks) 1056 pr_info("%d new suspected memory leaks (see " 1057 "/sys/kernel/debug/kmemleak)\n", new_leaks); 1058 1059} 1060 1061/* 1062 * Thread function performing automatic memory scanning. Unreferenced objects 1063 * at the end of a memory scan are reported but only the first time. 1064 */ 1065static int kmemleak_scan_thread(void *arg) 1066{ 1067 static int first_run = 1; 1068 1069 pr_info("Automatic memory scanning thread started\n"); 1070 1071 /* 1072 * Wait before the first scan to allow the system to fully initialize. 1073 */ 1074 if (first_run) { 1075 first_run = 0; 1076 ssleep(SECS_FIRST_SCAN); 1077 } 1078 1079 while (!kthread_should_stop()) { 1080 signed long timeout = jiffies_scan_wait; 1081 1082 mutex_lock(&scan_mutex); 1083 kmemleak_scan(); 1084 mutex_unlock(&scan_mutex); 1085 1086 /* wait before the next scan */ 1087 while (timeout && !kthread_should_stop()) 1088 timeout = schedule_timeout_interruptible(timeout); 1089 } 1090 1091 pr_info("Automatic memory scanning thread ended\n"); 1092 1093 return 0; 1094} 1095 1096/* 1097 * Start the automatic memory scanning thread. This function must be called 1098 * with the scan_mutex held. 1099 */ 1100void start_scan_thread(void) 1101{ 1102 if (scan_thread) 1103 return; 1104 scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); 1105 if (IS_ERR(scan_thread)) { 1106 pr_warning("Failed to create the scan thread\n"); 1107 scan_thread = NULL; 1108 } 1109} 1110 1111/* 1112 * Stop the automatic memory scanning thread. This function must be called 1113 * with the scan_mutex held. 1114 */ 1115void stop_scan_thread(void) 1116{ 1117 if (scan_thread) { 1118 kthread_stop(scan_thread); 1119 scan_thread = NULL; 1120 } 1121} 1122 1123/* 1124 * Iterate over the object_list and return the first valid object at or after 1125 * the required position with its use_count incremented. The function triggers 1126 * a memory scanning when the pos argument points to the first position. 1127 */ 1128static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) 1129{ 1130 struct kmemleak_object *object; 1131 loff_t n = *pos; 1132 1133 if (!n) 1134 reported_leaks = 0; 1135 if (reported_leaks >= REPORTS_NR) 1136 return NULL; 1137 1138 rcu_read_lock(); 1139 list_for_each_entry_rcu(object, &object_list, object_list) { 1140 if (n-- > 0) 1141 continue; 1142 if (get_object(object)) 1143 goto out; 1144 } 1145 object = NULL; 1146out: 1147 rcu_read_unlock(); 1148 return object; 1149} 1150 1151/* 1152 * Return the next object in the object_list. The function decrements the 1153 * use_count of the previous object and increases that of the next one. 1154 */ 1155static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1156{ 1157 struct kmemleak_object *prev_obj = v; 1158 struct kmemleak_object *next_obj = NULL; 1159 struct list_head *n = &prev_obj->object_list; 1160 1161 ++(*pos); 1162 if (reported_leaks >= REPORTS_NR) 1163 goto out; 1164 1165 rcu_read_lock(); 1166 list_for_each_continue_rcu(n, &object_list) { 1167 next_obj = list_entry(n, struct kmemleak_object, object_list); 1168 if (get_object(next_obj)) 1169 break; 1170 } 1171 rcu_read_unlock(); 1172out: 1173 put_object(prev_obj); 1174 return next_obj; 1175} 1176 1177/* 1178 * Decrement the use_count of the last object required, if any. 1179 */ 1180static void kmemleak_seq_stop(struct seq_file *seq, void *v) 1181{ 1182 if (v) 1183 put_object(v); 1184} 1185 1186/* 1187 * Print the information for an unreferenced object to the seq file. 1188 */ 1189static int kmemleak_seq_show(struct seq_file *seq, void *v) 1190{ 1191 struct kmemleak_object *object = v; 1192 unsigned long flags; 1193 1194 spin_lock_irqsave(&object->lock, flags); 1195 if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) { 1196 print_unreferenced(seq, object); 1197 reported_leaks++; 1198 } 1199 spin_unlock_irqrestore(&object->lock, flags); 1200 return 0; 1201} 1202 1203static const struct seq_operations kmemleak_seq_ops = { 1204 .start = kmemleak_seq_start, 1205 .next = kmemleak_seq_next, 1206 .stop = kmemleak_seq_stop, 1207 .show = kmemleak_seq_show, 1208}; 1209 1210static int kmemleak_open(struct inode *inode, struct file *file) 1211{ 1212 int ret = 0; 1213 1214 if (!atomic_read(&kmemleak_enabled)) 1215 return -EBUSY; 1216 1217 ret = mutex_lock_interruptible(&scan_mutex); 1218 if (ret < 0) 1219 goto out; 1220 if (file->f_mode & FMODE_READ) { 1221 ret = seq_open(file, &kmemleak_seq_ops); 1222 if (ret < 0) 1223 goto scan_unlock; 1224 } 1225 return ret; 1226 1227scan_unlock: 1228 mutex_unlock(&scan_mutex); 1229out: 1230 return ret; 1231} 1232 1233static int kmemleak_release(struct inode *inode, struct file *file) 1234{ 1235 int ret = 0; 1236 1237 if (file->f_mode & FMODE_READ) 1238 seq_release(inode, file); 1239 mutex_unlock(&scan_mutex); 1240 1241 return ret; 1242} 1243 1244/* 1245 * File write operation to configure kmemleak at run-time. The following 1246 * commands can be written to the /sys/kernel/debug/kmemleak file: 1247 * off - disable kmemleak (irreversible) 1248 * stack=on - enable the task stacks scanning 1249 * stack=off - disable the tasks stacks scanning 1250 * scan=on - start the automatic memory scanning thread 1251 * scan=off - stop the automatic memory scanning thread 1252 * scan=... - set the automatic memory scanning period in seconds (0 to 1253 * disable it) 1254 * scan - trigger a memory scan 1255 */ 1256static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, 1257 size_t size, loff_t *ppos) 1258{ 1259 char buf[64]; 1260 int buf_size; 1261 1262 if (!atomic_read(&kmemleak_enabled)) 1263 return -EBUSY; 1264 1265 buf_size = min(size, (sizeof(buf) - 1)); 1266 if (strncpy_from_user(buf, user_buf, buf_size) < 0) 1267 return -EFAULT; 1268 buf[buf_size] = 0; 1269 1270 if (strncmp(buf, "off", 3) == 0) 1271 kmemleak_disable(); 1272 else if (strncmp(buf, "stack=on", 8) == 0) 1273 kmemleak_stack_scan = 1; 1274 else if (strncmp(buf, "stack=off", 9) == 0) 1275 kmemleak_stack_scan = 0; 1276 else if (strncmp(buf, "scan=on", 7) == 0) 1277 start_scan_thread(); 1278 else if (strncmp(buf, "scan=off", 8) == 0) 1279 stop_scan_thread(); 1280 else if (strncmp(buf, "scan=", 5) == 0) { 1281 unsigned long secs; 1282 int err; 1283 1284 err = strict_strtoul(buf + 5, 0, &secs); 1285 if (err < 0) 1286 return err; 1287 stop_scan_thread(); 1288 if (secs) { 1289 jiffies_scan_wait = msecs_to_jiffies(secs * 1000); 1290 start_scan_thread(); 1291 } 1292 } else if (strncmp(buf, "scan", 4) == 0) 1293 kmemleak_scan(); 1294 else 1295 return -EINVAL; 1296 1297 /* ignore the rest of the buffer, only one command at a time */ 1298 *ppos += size; 1299 return size; 1300} 1301 1302static const struct file_operations kmemleak_fops = { 1303 .owner = THIS_MODULE, 1304 .open = kmemleak_open, 1305 .read = seq_read, 1306 .write = kmemleak_write, 1307 .llseek = seq_lseek, 1308 .release = kmemleak_release, 1309}; 1310 1311/* 1312 * Perform the freeing of the kmemleak internal objects after waiting for any 1313 * current memory scan to complete. 1314 */ 1315static int kmemleak_cleanup_thread(void *arg) 1316{ 1317 struct kmemleak_object *object; 1318 1319 mutex_lock(&scan_mutex); 1320 stop_scan_thread(); 1321 1322 rcu_read_lock(); 1323 list_for_each_entry_rcu(object, &object_list, object_list) 1324 delete_object(object->pointer); 1325 rcu_read_unlock(); 1326 mutex_unlock(&scan_mutex); 1327 1328 return 0; 1329} 1330 1331/* 1332 * Start the clean-up thread. 1333 */ 1334static void kmemleak_cleanup(void) 1335{ 1336 struct task_struct *cleanup_thread; 1337 1338 cleanup_thread = kthread_run(kmemleak_cleanup_thread, NULL, 1339 "kmemleak-clean"); 1340 if (IS_ERR(cleanup_thread)) 1341 pr_warning("Failed to create the clean-up thread\n"); 1342} 1343 1344/* 1345 * Disable kmemleak. No memory allocation/freeing will be traced once this 1346 * function is called. Disabling kmemleak is an irreversible operation. 1347 */ 1348static void kmemleak_disable(void) 1349{ 1350 /* atomically check whether it was already invoked */ 1351 if (atomic_cmpxchg(&kmemleak_error, 0, 1)) 1352 return; 1353 1354 /* stop any memory operation tracing */ 1355 atomic_set(&kmemleak_early_log, 0); 1356 atomic_set(&kmemleak_enabled, 0); 1357 1358 /* check whether it is too early for a kernel thread */ 1359 if (atomic_read(&kmemleak_initialized)) 1360 kmemleak_cleanup(); 1361 1362 pr_info("Kernel memory leak detector disabled\n"); 1363} 1364 1365/* 1366 * Allow boot-time kmemleak disabling (enabled by default). 1367 */ 1368static int kmemleak_boot_config(char *str) 1369{ 1370 if (!str) 1371 return -EINVAL; 1372 if (strcmp(str, "off") == 0) 1373 kmemleak_disable(); 1374 else if (strcmp(str, "on") != 0) 1375 return -EINVAL; 1376 return 0; 1377} 1378early_param("kmemleak", kmemleak_boot_config); 1379 1380/* 1381 * Kmemleak initialization. 1382 */ 1383void __init kmemleak_init(void) 1384{ 1385 int i; 1386 unsigned long flags; 1387 1388 jiffies_scan_yield = msecs_to_jiffies(MSECS_SCAN_YIELD); 1389 jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); 1390 jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); 1391 1392 object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); 1393 scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); 1394 INIT_PRIO_TREE_ROOT(&object_tree_root); 1395 1396 /* the kernel is still in UP mode, so disabling the IRQs is enough */ 1397 local_irq_save(flags); 1398 if (!atomic_read(&kmemleak_error)) { 1399 atomic_set(&kmemleak_enabled, 1); 1400 atomic_set(&kmemleak_early_log, 0); 1401 } 1402 local_irq_restore(flags); 1403 1404 /* 1405 * This is the point where tracking allocations is safe. Automatic 1406 * scanning is started during the late initcall. Add the early logged 1407 * callbacks to the kmemleak infrastructure. 1408 */ 1409 for (i = 0; i < crt_early_log; i++) { 1410 struct early_log *log = &early_log[i]; 1411 1412 switch (log->op_type) { 1413 case KMEMLEAK_ALLOC: 1414 kmemleak_alloc(log->ptr, log->size, log->min_count, 1415 GFP_KERNEL); 1416 break; 1417 case KMEMLEAK_FREE: 1418 kmemleak_free(log->ptr); 1419 break; 1420 case KMEMLEAK_NOT_LEAK: 1421 kmemleak_not_leak(log->ptr); 1422 break; 1423 case KMEMLEAK_IGNORE: 1424 kmemleak_ignore(log->ptr); 1425 break; 1426 case KMEMLEAK_SCAN_AREA: 1427 kmemleak_scan_area(log->ptr, log->offset, log->length, 1428 GFP_KERNEL); 1429 break; 1430 case KMEMLEAK_NO_SCAN: 1431 kmemleak_no_scan(log->ptr); 1432 break; 1433 default: 1434 WARN_ON(1); 1435 } 1436 } 1437} 1438 1439/* 1440 * Late initialization function. 1441 */ 1442static int __init kmemleak_late_init(void) 1443{ 1444 struct dentry *dentry; 1445 1446 atomic_set(&kmemleak_initialized, 1); 1447 1448 if (atomic_read(&kmemleak_error)) { 1449 /* 1450 * Some error occured and kmemleak was disabled. There is a 1451 * small chance that kmemleak_disable() was called immediately 1452 * after setting kmemleak_initialized and we may end up with 1453 * two clean-up threads but serialized by scan_mutex. 1454 */ 1455 kmemleak_cleanup(); 1456 return -ENOMEM; 1457 } 1458 1459 dentry = debugfs_create_file("kmemleak", S_IRUGO, NULL, NULL, 1460 &kmemleak_fops); 1461 if (!dentry) 1462 pr_warning("Failed to create the debugfs kmemleak file\n"); 1463 mutex_lock(&scan_mutex); 1464 start_scan_thread(); 1465 mutex_unlock(&scan_mutex); 1466 1467 pr_info("Kernel memory leak detector initialized\n"); 1468 1469 return 0; 1470} 1471late_initcall(kmemleak_late_init); 1472