diff options
Diffstat (limited to 'mm/kmemleak.c')
| -rw-r--r-- | mm/kmemleak.c | 260 |
1 files changed, 183 insertions, 77 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index a182f5ddaf68..1eddc0132f7f 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -14,14 +14,16 @@ * The following locks and mutexes are used by kmemleak: * * - kmemleak_lock (raw_spinlock_t): protects the object_list modifications and - * accesses to the object_tree_root. The object_list is the main list - * holding the metadata (struct kmemleak_object) for the allocated memory - * blocks. The object_tree_root is a red black tree used to look-up - * metadata based on a pointer to the corresponding memory block. The - * kmemleak_object structures are added to the object_list and - * object_tree_root in the create_object() function called from the - * kmemleak_alloc() callback and removed in delete_object() called from the - * kmemleak_free() callback + * accesses to the object_tree_root (or object_phys_tree_root). The + * object_list is the main list holding the metadata (struct kmemleak_object) + * for the allocated memory blocks. The object_tree_root and object_phys_tree_root + * are red black trees used to look-up metadata based on a pointer to the + * corresponding memory block. The object_phys_tree_root is for objects + * allocated with physical address. The kmemleak_object structures are + * added to the object_list and object_tree_root (or object_phys_tree_root) + * in the create_object() function called from the kmemleak_alloc() (or + * kmemleak_alloc_phys()) callback and removed in delete_object() called from + * the kmemleak_free() callback * - kmemleak_object.lock (raw_spinlock_t): protects a kmemleak_object. * Accesses to the metadata (e.g. count) are protected by this lock. Note * that some members of this structure may be protected by other means @@ -172,6 +174,8 @@ struct kmemleak_object { #define OBJECT_NO_SCAN (1 << 2) /* flag set to fully scan the object when scan_area allocation failed */ #define OBJECT_FULL_SCAN (1 << 3) +/* flag set for object allocated with physical address */ +#define OBJECT_PHYS (1 << 4) #define HEX_PREFIX " " /* number of bytes to print per line; must be 16 or 32 */ @@ -193,7 +197,9 @@ static int mem_pool_free_count = ARRAY_SIZE(mem_pool); static LIST_HEAD(mem_pool_free_list); /* search tree for object boundaries */ static struct rb_root object_tree_root = RB_ROOT; -/* protecting the access to object_list and object_tree_root */ +/* search tree for object (with OBJECT_PHYS flag) boundaries */ +static struct rb_root object_phys_tree_root = RB_ROOT; +/* protecting the access to object_list, object_tree_root (or object_phys_tree_root) */ static DEFINE_RAW_SPINLOCK(kmemleak_lock); /* allocation caches for kmemleak internal data */ @@ -285,6 +291,9 @@ static void hex_dump_object(struct seq_file *seq, const u8 *ptr = (const u8 *)object->pointer; size_t len; + if (WARN_ON_ONCE(object->flags & OBJECT_PHYS)) + return; + /* limit the number of lines to HEX_MAX_LINES */ len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE); @@ -378,9 +387,11 @@ static void dump_object_info(struct kmemleak_object *object) * beginning of the memory block are allowed. The kmemleak_lock must be held * when calling this function. */ -static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) +static struct kmemleak_object *__lookup_object(unsigned long ptr, int alias, + bool is_phys) { - struct rb_node *rb = object_tree_root.rb_node; + struct rb_node *rb = is_phys ? object_phys_tree_root.rb_node : + object_tree_root.rb_node; unsigned long untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); while (rb) { @@ -406,6 +417,12 @@ static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) return NULL; } +/* Look-up a kmemleak object which allocated with virtual address. */ +static struct kmemleak_object *lookup_object(unsigned long ptr, int alias) +{ + return __lookup_object(ptr, alias, false); +} + /* * Increment the object use_count. Return 1 if successful or 0 otherwise. Note * that once an object's use_count reached 0, the RCU freeing was already @@ -515,14 +532,15 @@ static void put_object(struct kmemleak_object *object) /* * Look up an object in the object search tree and increase its use_count. */ -static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) +static struct kmemleak_object *__find_and_get_object(unsigned long ptr, int alias, + bool is_phys) { unsigned long flags; struct kmemleak_object *object; rcu_read_lock(); raw_spin_lock_irqsave(&kmemleak_lock, flags); - object = lookup_object(ptr, alias); + object = __lookup_object(ptr, alias, is_phys); raw_spin_unlock_irqrestore(&kmemleak_lock, flags); /* check whether the object is still available */ @@ -533,28 +551,39 @@ static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) return object; } +/* Look up and get an object which allocated with virtual address. */ +static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) +{ + return __find_and_get_object(ptr, alias, false); +} + /* - * Remove an object from the object_tree_root and object_list. Must be called - * with the kmemleak_lock held _if_ kmemleak is still enabled. + * Remove an object from the object_tree_root (or object_phys_tree_root) + * and object_list. Must be called with the kmemleak_lock held _if_ kmemleak + * is still enabled. */ static void __remove_object(struct kmemleak_object *object) { - rb_erase(&object->rb_node, &object_tree_root); + rb_erase(&object->rb_node, object->flags & OBJECT_PHYS ? + &object_phys_tree_root : + &object_tree_root); list_del_rcu(&object->object_list); } /* * Look up an object in the object search tree and remove it from both - * object_tree_root and object_list. The returned object's use_count should be - * at least 1, as initially set by create_object(). + * object_tree_root (or object_phys_tree_root) and object_list. The + * returned object's use_count should be at least 1, as initially set + * by create_object(). */ -static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias) +static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias, + bool is_phys) { unsigned long flags; struct kmemleak_object *object; raw_spin_lock_irqsave(&kmemleak_lock, flags); - object = lookup_object(ptr, alias); + object = __lookup_object(ptr, alias, is_phys); if (object) __remove_object(object); raw_spin_unlock_irqrestore(&kmemleak_lock, flags); @@ -572,10 +601,12 @@ static int __save_stack_trace(unsigned long *trace) /* * Create the metadata (struct kmemleak_object) corresponding to an allocated - * memory block and add it to the object_list and object_tree_root. + * memory block and add it to the object_list and object_tree_root (or + * object_phys_tree_root). */ -static struct kmemleak_object *create_object(unsigned long ptr, size_t size, - int min_count, gfp_t gfp) +static struct kmemleak_object *__create_object(unsigned long ptr, size_t size, + int min_count, gfp_t gfp, + bool is_phys) { unsigned long flags; struct kmemleak_object *object, *parent; @@ -595,7 +626,7 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, INIT_HLIST_HEAD(&object->area_list); raw_spin_lock_init(&object->lock); atomic_set(&object->use_count, 1); - object->flags = OBJECT_ALLOCATED; + object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0); object->pointer = ptr; object->size = kfence_ksize((void *)ptr) ?: size; object->excess_ref = 0; @@ -628,9 +659,16 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, raw_spin_lock_irqsave(&kmemleak_lock, flags); untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); - min_addr = min(min_addr, untagged_ptr); - max_addr = max(max_addr, untagged_ptr + size); - link = &object_tree_root.rb_node; + /* + * Only update min_addr and max_addr with object + * storing virtual address. + */ + if (!is_phys) { + min_addr = min(min_addr, untagged_ptr); + max_addr = max(max_addr, untagged_ptr + size); + } + link = is_phys ? &object_phys_tree_root.rb_node : + &object_tree_root.rb_node; rb_parent = NULL; while (*link) { rb_parent = *link; @@ -654,7 +692,8 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, } } rb_link_node(&object->rb_node, rb_parent, link); - rb_insert_color(&object->rb_node, &object_tree_root); + rb_insert_color(&object->rb_node, is_phys ? &object_phys_tree_root : + &object_tree_root); list_add_tail_rcu(&object->object_list, &object_list); out: @@ -662,6 +701,20 @@ out: return object; } +/* Create kmemleak object which allocated with virtual address. */ +static struct kmemleak_object *create_object(unsigned long ptr, size_t size, + int min_count, gfp_t gfp) +{ + return __create_object(ptr, size, min_count, gfp, false); +} + +/* Create kmemleak object which allocated with physical address. */ +static struct kmemleak_object *create_object_phys(unsigned long ptr, size_t size, + int min_count, gfp_t gfp) +{ + return __create_object(ptr, size, min_count, gfp, true); +} + /* * Mark the object as not allocated and schedule RCU freeing via put_object(). */ @@ -690,7 +743,7 @@ static void delete_object_full(unsigned long ptr) { struct kmemleak_object *object; - object = find_and_remove_object(ptr, 0); + object = find_and_remove_object(ptr, 0, false); if (!object) { #ifdef DEBUG kmemleak_warn("Freeing unknown object at 0x%08lx\n", @@ -706,12 +759,12 @@ static void delete_object_full(unsigned long ptr) * delete it. If the memory block is partially freed, the function may create * additional metadata for the remaining parts of the block. */ -static void delete_object_part(unsigned long ptr, size_t size) +static void delete_object_part(unsigned long ptr, size_t size, bool is_phys) { struct kmemleak_object *object; unsigned long start, end; - object = find_and_remove_object(ptr, 1); + object = find_and_remove_object(ptr, 1, is_phys); if (!object) { #ifdef DEBUG kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n", @@ -728,11 +781,11 @@ static void delete_object_part(unsigned long ptr, size_t size) start = object->pointer; end = object->pointer + object->size; if (ptr > start) - create_object(start, ptr - start, object->min_count, - GFP_KERNEL); + __create_object(start, ptr - start, object->min_count, + GFP_KERNEL, is_phys); if (ptr + size < end) - create_object(ptr + size, end - ptr - size, object->min_count, - GFP_KERNEL); + __create_object(ptr + size, end - ptr - size, object->min_count, + GFP_KERNEL, is_phys); __delete_object(object); } @@ -753,11 +806,11 @@ static void paint_it(struct kmemleak_object *object, int color) raw_spin_unlock_irqrestore(&object->lock, flags); } -static void paint_ptr(unsigned long ptr, int color) +static void paint_ptr(unsigned long ptr, int color, bool is_phys) { struct kmemleak_object *object; - object = find_and_get_object(ptr, 0); + object = __find_and_get_object(ptr, 0, is_phys); if (!object) { kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n", ptr, @@ -775,16 +828,16 @@ static void paint_ptr(unsigned long ptr, int color) */ static void make_gray_object(unsigned long ptr) { - paint_ptr(ptr, KMEMLEAK_GREY); + paint_ptr(ptr, KMEMLEAK_GREY, false); } /* * Mark the object as black-colored so that it is ignored from scans and * reporting. */ -static void make_black_object(unsigned long ptr) +static void make_black_object(unsigned long ptr, bool is_phys) { - paint_ptr(ptr, KMEMLEAK_BLACK); + paint_ptr(ptr, KMEMLEAK_BLACK, is_phys); } /* @@ -990,7 +1043,7 @@ void __ref kmemleak_free_part(const void *ptr, size_t size) pr_debug("%s(0x%p)\n", __func__, ptr); if (kmemleak_enabled && ptr && !IS_ERR(ptr)) - delete_object_part((unsigned long)ptr, size); + delete_object_part((unsigned long)ptr, size, false); } EXPORT_SYMBOL_GPL(kmemleak_free_part); @@ -1078,7 +1131,7 @@ void __ref kmemleak_ignore(const void *ptr) pr_debug("%s(0x%p)\n", __func__, ptr); if (kmemleak_enabled && ptr && !IS_ERR(ptr)) - make_black_object((unsigned long)ptr); + make_black_object((unsigned long)ptr, false); } EXPORT_SYMBOL(kmemleak_ignore); @@ -1125,15 +1178,18 @@ EXPORT_SYMBOL(kmemleak_no_scan); * address argument * @phys: physical address of the object * @size: size of the object - * @min_count: minimum number of references to this object. - * See kmemleak_alloc() * @gfp: kmalloc() flags used for kmemleak internal memory allocations */ -void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count, - gfp_t gfp) +void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, gfp_t gfp) { - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn) - kmemleak_alloc(__va(phys), size, min_count, gfp); + pr_debug("%s(0x%pa, %zu)\n", __func__, &phys, size); + + if (kmemleak_enabled) + /* + * Create object with OBJECT_PHYS flag and + * assume min_count 0. + */ + create_object_phys((unsigned long)phys, size, 0, gfp); } EXPORT_SYMBOL(kmemleak_alloc_phys); @@ -1146,22 +1202,12 @@ EXPORT_SYMBOL(kmemleak_alloc_phys); */ void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size) { - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn) - kmemleak_free_part(__va(phys), size); -} -EXPORT_SYMBOL(kmemleak_free_part_phys); + pr_debug("%s(0x%pa)\n", __func__, &phys); -/** - * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical - * address argument - * @phys: physical address of the object - */ -void __ref kmemleak_not_leak_phys(phys_addr_t phys) -{ - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn) - kmemleak_not_leak(__va(phys)); + if (kmemleak_enabled) + delete_object_part((unsigned long)phys, size, true); } -EXPORT_SYMBOL(kmemleak_not_leak_phys); +EXPORT_SYMBOL(kmemleak_free_part_phys); /** * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical @@ -1170,8 +1216,10 @@ EXPORT_SYMBOL(kmemleak_not_leak_phys); */ void __ref kmemleak_ignore_phys(phys_addr_t phys) { - if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn) - kmemleak_ignore(__va(phys)); + pr_debug("%s(0x%pa)\n", __func__, &phys); + + if (kmemleak_enabled) + make_black_object((unsigned long)phys, true); } EXPORT_SYMBOL(kmemleak_ignore_phys); @@ -1182,6 +1230,9 @@ static bool update_checksum(struct kmemleak_object *object) { u32 old_csum = object->checksum; + if (WARN_ON_ONCE(object->flags & OBJECT_PHYS)) + return false; + kasan_disable_current(); kcsan_disable_current(); object->checksum = crc32(0, kasan_reset_tag((void *)object->pointer), object->size); @@ -1335,6 +1386,7 @@ static void scan_object(struct kmemleak_object *object) { struct kmemleak_scan_area *area; unsigned long flags; + void *obj_ptr; /* * Once the object->lock is acquired, the corresponding memory block @@ -1346,10 +1398,15 @@ static void scan_object(struct kmemleak_object *object) if (!(object->flags & OBJECT_ALLOCATED)) /* already freed object */ goto out; + + obj_ptr = object->flags & OBJECT_PHYS ? + __va((phys_addr_t)object->pointer) : + (void *)object->pointer; + if (hlist_empty(&object->area_list) || object->flags & OBJECT_FULL_SCAN) { - void *start = (void *)object->pointer; - void *end = (void *)(object->pointer + object->size); + void *start = obj_ptr; + void *end = obj_ptr + object->size; void *next; do { @@ -1413,18 +1470,21 @@ static void scan_gray_list(void) */ static void kmemleak_scan(void) { - unsigned long flags; struct kmemleak_object *object; struct zone *zone; int __maybe_unused i; int new_leaks = 0; + int loop1_cnt = 0; jiffies_last_scan = jiffies; /* prepare the kmemleak_object's */ rcu_read_lock(); list_for_each_entry_rcu(object, &object_list, object_list) { - raw_spin_lock_irqsave(&object->lock, flags); + bool obj_pinned = false; + + loop1_cnt++; + raw_spin_lock_irq(&object->lock); #ifdef DEBUG /* * With a few exceptions there should be a maximum of @@ -1436,12 +1496,45 @@ static void kmemleak_scan(void) dump_object_info(object); } #endif + + /* ignore objects outside lowmem (paint them black) */ + if ((object->flags & OBJECT_PHYS) && + !(object->flags & OBJECT_NO_SCAN)) { + unsigned long phys = object->pointer; + + if (PHYS_PFN(phys) < min_low_pfn || + PHYS_PFN(phys + object->size) >= max_low_pfn) + __paint_it(object, KMEMLEAK_BLACK); + } + /* reset the reference count (whiten the object) */ object->count = 0; - if (color_gray(object) && get_object(object)) + if (color_gray(object) && get_object(object)) { list_add_tail(&object->gray_list, &gray_list); + obj_pinned = true; + } - raw_spin_unlock_irqrestore(&object->lock, flags); + raw_spin_unlock_irq(&object->lock); + + /* + * Do a cond_resched() to avoid soft lockup every 64k objects. + * Make sure a reference has been taken so that the object + * won't go away without RCU read lock. + */ + if (!(loop1_cnt & 0xffff)) { + if (!obj_pinned && !get_object(object)) { + /* Try the next object instead */ + loop1_cnt--; + continue; + } + + rcu_read_unlock(); + cond_resched(); + rcu_read_lock(); + + if (!obj_pinned) + put_object(object); + } } rcu_read_unlock(); @@ -1509,14 +1602,21 @@ static void kmemleak_scan(void) */ rcu_read_lock(); list_for_each_entry_rcu(object, &object_list, object_list) { - raw_spin_lock_irqsave(&object->lock, flags); + /* + * This is racy but we can save the overhead of lock/unlock + * calls. The missed objects, if any, should be caught in + * the next scan. + */ + if (!color_white(object)) + continue; + raw_spin_lock_irq(&object->lock); if (color_white(object) && (object->flags & OBJECT_ALLOCATED) && update_checksum(object) && get_object(object)) { /* color it gray temporarily */ object->count = object->min_count; list_add_tail(&object->gray_list, &gray_list); } - raw_spin_unlock_irqrestore(&object->lock, flags); + raw_spin_unlock_irq(&object->lock); } rcu_read_unlock(); @@ -1536,7 +1636,14 @@ static void kmemleak_scan(void) */ rcu_read_lock(); list_for_each_entry_rcu(object, &object_list, object_list) { - raw_spin_lock_irqsave(&object->lock, flags); + /* + * This is racy but we can save the overhead of lock/unlock + * calls. The missed objects, if any, should be caught in + * the next scan. + */ + if (!color_white(object)) + continue; + raw_spin_lock_irq(&object->lock); if (unreferenced_object(object) && !(object->flags & OBJECT_REPORTED)) { object->flags |= OBJECT_REPORTED; @@ -1546,7 +1653,7 @@ static void kmemleak_scan(void) new_leaks++; } - raw_spin_unlock_irqrestore(&object->lock, flags); + raw_spin_unlock_irq(&object->lock); } rcu_read_unlock(); @@ -1748,15 +1855,14 @@ static int dump_str_object_info(const char *str) static void kmemleak_clear(void) { struct kmemleak_object *object; - unsigned long flags; rcu_read_lock(); list_for_each_entry_rcu(object, &object_list, object_list) { - raw_spin_lock_irqsave(&object->lock, flags); + raw_spin_lock_irq(&object->lock); if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) __paint_it(object, KMEMLEAK_GREY); - raw_spin_unlock_irqrestore(&object->lock, flags); + raw_spin_unlock_irq(&object->lock); } rcu_read_unlock(); |