diff options
Diffstat (limited to 'mm/kmemleak.c')
| -rw-r--r-- | mm/kmemleak.c | 917 |
1 files changed, 639 insertions, 278 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index e362dc3d2028..1ac56ceb29b6 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -13,15 +13,16 @@ * * 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 + * - kmemleak_lock (raw_spinlock_t): protects the object_list as well as + * del_state modifications and accesses to the object trees + * (object_tree_root, object_phys_tree_root, object_percpu_tree_root). The + * object_list is the main list holding the metadata (struct + * kmemleak_object) for the allocated memory blocks. The object trees are + * red black trees 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 the object tree root in the create_object() function + * called from the kmemleak_alloc{,_phys,_percpu}() callback and removed in + * delete_object() called from the kmemleak_free{,_phys,_percpu}() 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 @@ -77,6 +78,7 @@ #include <linux/mutex.h> #include <linux/rcupdate.h> #include <linux/stacktrace.h> +#include <linux/stackdepot.h> #include <linux/cache.h> #include <linux/percpu.h> #include <linux/memblock.h> @@ -97,6 +99,7 @@ #include <linux/atomic.h> #include <linux/kasan.h> +#include <linux/kfence.h> #include <linux/kmemleak.h> #include <linux/memory_hotplug.h> @@ -111,11 +114,6 @@ #define BYTES_PER_POINTER sizeof(void *) -/* GFP bitmask for kmemleak internal allocations */ -#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \ - __GFP_NORETRY | __GFP_NOMEMALLOC | \ - __GFP_NOWARN) - /* scanning area inside a memory block */ struct kmemleak_scan_area { struct hlist_node node; @@ -143,6 +141,7 @@ struct kmemleak_object { struct rcu_head rcu; /* object_list lockless traversal */ /* object usage count; object freed when use_count == 0 */ atomic_t use_count; + unsigned int del_state; /* deletion state */ unsigned long pointer; size_t size; /* pass surplus references to this pointer */ @@ -153,10 +152,9 @@ struct kmemleak_object { int count; /* checksum for detecting modified objects */ u32 checksum; + depot_stack_handle_t trace_handle; /* memory ranges to be scanned inside an object (empty for all) */ struct hlist_head area_list; - unsigned long trace[MAX_TRACE]; - unsigned int trace_len; unsigned long jiffies; /* creation timestamp */ pid_t pid; /* pid of the current task */ char comm[TASK_COMM_LEN]; /* executable name */ @@ -170,6 +168,15 @@ 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) +/* flag set for per-CPU pointers */ +#define OBJECT_PERCPU (1 << 5) + +/* set when __remove_object() called */ +#define DELSTATE_REMOVED (1 << 0) +/* set to temporarily prevent deletion from object_list */ +#define DELSTATE_NO_DELETE (1 << 1) #define HEX_PREFIX " " /* number of bytes to print per line; must be 16 or 32 */ @@ -191,7 +198,11 @@ 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; +/* search tree for object (with OBJECT_PERCPU flag) boundaries */ +static struct rb_root object_percpu_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 */ @@ -199,13 +210,11 @@ static struct kmem_cache *object_cache; static struct kmem_cache *scan_area_cache; /* set if tracing memory operations is enabled */ -static int kmemleak_enabled = 1; +static int kmemleak_enabled __read_mostly = 1; /* same as above but only for the kmemleak_free() callback */ -static int kmemleak_free_enabled = 1; +static int kmemleak_free_enabled __read_mostly = 1; /* set in the late_initcall if there were no errors */ -static int kmemleak_initialized; -/* set if a kmemleak warning was issued */ -static int kmemleak_warning; +static int kmemleak_late_initialized; /* set if a fatal kmemleak error has occurred */ static int kmemleak_error; @@ -213,12 +222,16 @@ static int kmemleak_error; static unsigned long min_addr = ULONG_MAX; static unsigned long max_addr; +/* minimum and maximum address that may be valid per-CPU pointers */ +static unsigned long min_percpu_addr = ULONG_MAX; +static unsigned long max_percpu_addr; + static struct task_struct *scan_thread; /* used to avoid reporting of recently allocated objects */ static unsigned long jiffies_min_age; static unsigned long jiffies_last_scan; /* delay between automatic memory scannings */ -static signed long jiffies_scan_wait; +static unsigned long jiffies_scan_wait; /* enables or disables the task stacks scanning */ static int kmemleak_stack_scan = 1; /* protects the memory scanning, parameters and debug/kmemleak file access */ @@ -239,7 +252,6 @@ static void kmemleak_disable(void); #define kmemleak_warn(x...) do { \ pr_warn(x); \ dump_stack(); \ - kmemleak_warning = 1; \ } while (0) /* @@ -283,13 +295,23 @@ 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; + + if (object->flags & OBJECT_PERCPU) + ptr = (const u8 *)this_cpu_ptr((void __percpu *)object->pointer); + /* limit the number of lines to HEX_MAX_LINES */ len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE); - warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len); + if (object->flags & OBJECT_PERCPU) + warn_or_seq_printf(seq, " hex dump (first %zu bytes on cpu %d):\n", + len, raw_smp_processor_id()); + else + warn_or_seq_printf(seq, " hex dump (first %zu bytes):\n", len); kasan_disable_current(); warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE, - HEX_GROUP_SIZE, ptr, len, HEX_ASCII); + HEX_GROUP_SIZE, kasan_reset_tag((void *)ptr), len, HEX_ASCII); kasan_enable_current(); } @@ -300,8 +322,6 @@ static void hex_dump_object(struct seq_file *seq, * sufficient references to it (count >= min_count) * - black - ignore, it doesn't contain references (e.g. text section) * (min_count == -1). No function defined for this color. - * Newly created objects don't have any color assigned (object->count == -1) - * before the next memory scan when they become white. */ static bool color_white(const struct kmemleak_object *object) { @@ -327,6 +347,15 @@ static bool unreferenced_object(struct kmemleak_object *object) jiffies_last_scan); } +static const char *__object_type_str(struct kmemleak_object *object) +{ + if (object->flags & OBJECT_PHYS) + return " (phys)"; + if (object->flags & OBJECT_PERCPU) + return " (percpu)"; + return ""; +} + /* * Printing of the unreferenced objects information to the seq file. The * print_unreferenced function must be called with the object->lock held. @@ -335,19 +364,21 @@ static void print_unreferenced(struct seq_file *seq, struct kmemleak_object *object) { int i; - unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); - - warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", - object->pointer, object->size); - warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n", - object->comm, object->pid, object->jiffies, - msecs_age / 1000, msecs_age % 1000); + unsigned long *entries; + unsigned int nr_entries; + + nr_entries = stack_depot_fetch(object->trace_handle, &entries); + warn_or_seq_printf(seq, "unreferenced object%s 0x%08lx (size %zu):\n", + __object_type_str(object), + object->pointer, object->size); + warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", + object->comm, object->pid, object->jiffies); hex_dump_object(seq, object); - warn_or_seq_printf(seq, " backtrace:\n"); + warn_or_seq_printf(seq, " backtrace (crc %x):\n", object->checksum); - for (i = 0; i < object->trace_len; i++) { - void *ptr = (void *)object->trace[i]; - warn_or_seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); + for (i = 0; i < nr_entries; i++) { + void *ptr = (void *)entries[i]; + warn_or_seq_printf(seq, " %pS\n", ptr); } } @@ -358,8 +389,8 @@ static void print_unreferenced(struct seq_file *seq, */ static void dump_object_info(struct kmemleak_object *object) { - pr_notice("Object 0x%08lx (size %zu):\n", - object->pointer, object->size); + pr_notice("Object%s 0x%08lx (size %zu):\n", + __object_type_str(object), object->pointer, object->size); pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", object->comm, object->pid, object->jiffies); pr_notice(" min_count = %d\n", object->min_count); @@ -367,7 +398,17 @@ static void dump_object_info(struct kmemleak_object *object) pr_notice(" flags = 0x%x\n", object->flags); pr_notice(" checksum = %u\n", object->checksum); pr_notice(" backtrace:\n"); - stack_trace_print(object->trace, object->trace_len, 4); + if (object->trace_handle) + stack_depot_print(object->trace_handle); +} + +static struct rb_root *object_tree(unsigned long objflags) +{ + if (objflags & OBJECT_PHYS) + return &object_phys_tree_root; + if (objflags & OBJECT_PERCPU) + return &object_percpu_tree_root; + return &object_tree_root; } /* @@ -376,29 +417,47 @@ 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, + unsigned int objflags) { - struct rb_node *rb = object_tree_root.rb_node; + struct rb_node *rb = object_tree(objflags)->rb_node; + unsigned long untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); while (rb) { - struct kmemleak_object *object = - rb_entry(rb, struct kmemleak_object, rb_node); - if (ptr < object->pointer) + struct kmemleak_object *object; + unsigned long untagged_objp; + + object = rb_entry(rb, struct kmemleak_object, rb_node); + untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer); + + if (untagged_ptr < untagged_objp) rb = object->rb_node.rb_left; - else if (object->pointer + object->size <= ptr) + else if (untagged_objp + object->size <= untagged_ptr) rb = object->rb_node.rb_right; - else if (object->pointer == ptr || alias) + else if (untagged_objp == untagged_ptr || alias) return object; else { + /* + * Printk deferring due to the kmemleak_lock held. + * This is done to avoid deadlock. + */ + printk_deferred_enter(); kmemleak_warn("Found object by alias at 0x%08lx\n", ptr); dump_object_info(object); + printk_deferred_exit(); break; } } 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, 0); +} + /* * 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 @@ -417,10 +476,12 @@ static struct kmemleak_object *mem_pool_alloc(gfp_t gfp) { unsigned long flags; struct kmemleak_object *object; + bool warn = false; /* try the slab allocator first */ if (object_cache) { - object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); + object = kmem_cache_alloc_noprof(object_cache, + gfp_nested_mask(gfp)); if (object) return object; } @@ -434,8 +495,10 @@ static struct kmemleak_object *mem_pool_alloc(gfp_t gfp) else if (mem_pool_free_count) object = &mem_pool[--mem_pool_free_count]; else - pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE\n"); + warn = true; raw_spin_unlock_irqrestore(&kmemleak_lock, flags); + if (warn) + pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE\n"); return object; } @@ -508,14 +571,15 @@ 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, + unsigned int objflags) { 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, objflags); raw_spin_unlock_irqrestore(&kmemleak_lock, flags); /* check whether the object is still available */ @@ -526,54 +590,77 @@ 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, 0); +} + /* - * 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 its object tree 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); - list_del_rcu(&object->object_list); + rb_erase(&object->rb_node, object_tree(object->flags)); + if (!(object->del_state & DELSTATE_NO_DELETE)) + list_del_rcu(&object->object_list); + object->del_state |= DELSTATE_REMOVED; +} + +static struct kmemleak_object *__find_and_remove_object(unsigned long ptr, + int alias, + unsigned int objflags) +{ + struct kmemleak_object *object; + + object = __lookup_object(ptr, alias, objflags); + if (object) + __remove_object(object); + + return object; } /* - * 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(). + * 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(). */ -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, + unsigned int objflags) { unsigned long flags; struct kmemleak_object *object; raw_spin_lock_irqsave(&kmemleak_lock, flags); - object = lookup_object(ptr, alias); - if (object) - __remove_object(object); + object = __find_and_remove_object(ptr, alias, objflags); raw_spin_unlock_irqrestore(&kmemleak_lock, flags); return object; } -/* - * Save stack trace to the given array of MAX_TRACE size. - */ -static int __save_stack_trace(unsigned long *trace) +static noinline depot_stack_handle_t set_track_prepare(void) { - return stack_trace_save(trace, MAX_TRACE, 2); + depot_stack_handle_t trace_handle; + unsigned long entries[MAX_TRACE]; + unsigned int nr_entries; + + /* + * Use object_cache to determine whether kmemleak_init() has + * been invoked. stack_depot_early_init() is called before + * kmemleak_init() in mm_core_init(). + */ + if (!object_cache) + return 0; + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3); + trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT); + + return trace_handle; } -/* - * Create the metadata (struct kmemleak_object) corresponding to an allocated - * memory block and add it to the object_list and object_tree_root. - */ -static struct kmemleak_object *create_object(unsigned long ptr, size_t size, - int min_count, gfp_t gfp) +static struct kmemleak_object *__alloc_object(gfp_t gfp) { - unsigned long flags; - struct kmemleak_object *object, *parent; - struct rb_node **link, *rb_parent; - unsigned long untagged_ptr; + struct kmemleak_object *object; object = mem_pool_alloc(gfp); if (!object) { @@ -587,22 +674,18 @@ 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->pointer = ptr; - object->size = size; object->excess_ref = 0; - object->min_count = min_count; object->count = 0; /* white color initially */ - object->jiffies = jiffies; object->checksum = 0; + object->del_state = 0; /* task information */ - if (in_irq()) { + if (in_hardirq()) { object->pid = 0; - strncpy(object->comm, "hardirq", sizeof(object->comm)); + strscpy(object->comm, "hardirq"); } else if (in_serving_softirq()) { object->pid = 0; - strncpy(object->comm, "softirq", sizeof(object->comm)); + strscpy(object->comm, "softirq"); } else { object->pid = current->pid; /* @@ -611,27 +694,59 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, * dependency issues with current->alloc_lock. In the worst * case, the command line is not correct. */ - strncpy(object->comm, current->comm, sizeof(object->comm)); + strscpy(object->comm, current->comm); } /* kernel backtrace */ - object->trace_len = __save_stack_trace(object->trace); + object->trace_handle = set_track_prepare(); - raw_spin_lock_irqsave(&kmemleak_lock, flags); + return object; +} + +static int __link_object(struct kmemleak_object *object, unsigned long ptr, + size_t size, int min_count, unsigned int objflags) +{ + + struct kmemleak_object *parent; + struct rb_node **link, *rb_parent; + unsigned long untagged_ptr; + unsigned long untagged_objp; + + object->flags = OBJECT_ALLOCATED | objflags; + object->pointer = ptr; + object->size = kfence_ksize((void *)ptr) ?: size; + object->min_count = min_count; + object->jiffies = jiffies; 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. And update min_percpu_addr max_percpu_addr for per-CPU + * objects. + */ + if (objflags & OBJECT_PERCPU) { + min_percpu_addr = min(min_percpu_addr, untagged_ptr); + max_percpu_addr = max(max_percpu_addr, untagged_ptr + size); + } else if (!(objflags & OBJECT_PHYS)) { + min_addr = min(min_addr, untagged_ptr); + max_addr = max(max_addr, untagged_ptr + size); + } + link = &object_tree(objflags)->rb_node; rb_parent = NULL; while (*link) { rb_parent = *link; parent = rb_entry(rb_parent, struct kmemleak_object, rb_node); - if (ptr + size <= parent->pointer) + untagged_objp = (unsigned long)kasan_reset_tag((void *)parent->pointer); + if (untagged_ptr + size <= untagged_objp) link = &parent->rb_node.rb_left; - else if (parent->pointer + parent->size <= ptr) + else if (untagged_objp + parent->size <= untagged_ptr) link = &parent->rb_node.rb_right; else { + /* + * Printk deferring due to the kmemleak_lock held. + * This is done to avoid deadlock. + */ + printk_deferred_enter(); kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n", ptr); /* @@ -639,18 +754,58 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, * be freed while the kmemleak_lock is held. */ dump_object_info(parent); - kmem_cache_free(object_cache, object); - object = NULL; - goto out; + printk_deferred_exit(); + return -EEXIST; } } rb_link_node(&object->rb_node, rb_parent, link); - rb_insert_color(&object->rb_node, &object_tree_root); - + rb_insert_color(&object->rb_node, object_tree(objflags)); list_add_tail_rcu(&object->object_list, &object_list); -out: + + return 0; +} + +/* + * Create the metadata (struct kmemleak_object) corresponding to an allocated + * memory block and add it to the object_list and object tree. + */ +static void __create_object(unsigned long ptr, size_t size, + int min_count, gfp_t gfp, unsigned int objflags) +{ + struct kmemleak_object *object; + unsigned long flags; + int ret; + + object = __alloc_object(gfp); + if (!object) + return; + + raw_spin_lock_irqsave(&kmemleak_lock, flags); + ret = __link_object(object, ptr, size, min_count, objflags); raw_spin_unlock_irqrestore(&kmemleak_lock, flags); - return object; + if (ret) + mem_pool_free(object); +} + +/* Create kmemleak object which allocated with virtual address. */ +static void create_object(unsigned long ptr, size_t size, + int min_count, gfp_t gfp) +{ + __create_object(ptr, size, min_count, gfp, 0); +} + +/* Create kmemleak object which allocated with physical address. */ +static void create_object_phys(unsigned long ptr, size_t size, + int min_count, gfp_t gfp) +{ + __create_object(ptr, size, min_count, gfp, OBJECT_PHYS); +} + +/* Create kmemleak object corresponding to a per-CPU allocation. */ +static void create_object_percpu(unsigned long ptr, size_t size, + int min_count, gfp_t gfp) +{ + __create_object(ptr, size, min_count, gfp, OBJECT_PERCPU); } /* @@ -677,11 +832,11 @@ static void __delete_object(struct kmemleak_object *object) * Look up the metadata (struct kmemleak_object) corresponding to ptr and * delete it. */ -static void delete_object_full(unsigned long ptr) +static void delete_object_full(unsigned long ptr, unsigned int objflags) { struct kmemleak_object *object; - object = find_and_remove_object(ptr, 0); + object = find_and_remove_object(ptr, 0, objflags); if (!object) { #ifdef DEBUG kmemleak_warn("Freeing unknown object at 0x%08lx\n", @@ -697,19 +852,24 @@ 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, + unsigned int objflags) { - struct kmemleak_object *object; - unsigned long start, end; + struct kmemleak_object *object, *object_l, *object_r; + unsigned long start, end, flags; - object = find_and_remove_object(ptr, 1); - if (!object) { -#ifdef DEBUG - kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n", - ptr, size); -#endif + object_l = __alloc_object(GFP_KERNEL); + if (!object_l) return; - } + + object_r = __alloc_object(GFP_KERNEL); + if (!object_r) + goto out; + + raw_spin_lock_irqsave(&kmemleak_lock, flags); + object = __find_and_remove_object(ptr, 1, objflags); + if (!object) + goto unlock; /* * Create one or two objects that may result from the memory block @@ -718,14 +878,31 @@ 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); - if (ptr + size < end) - create_object(ptr + size, end - ptr - size, object->min_count, - GFP_KERNEL); + if ((ptr > start) && + !__link_object(object_l, start, ptr - start, + object->min_count, objflags)) + object_l = NULL; + if ((ptr + size < end) && + !__link_object(object_r, ptr + size, end - ptr - size, + object->min_count, objflags)) + object_r = NULL; + +unlock: + raw_spin_unlock_irqrestore(&kmemleak_lock, flags); + if (object) { + __delete_object(object); + } else { +#ifdef DEBUG + kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu)\n", + ptr, size); +#endif + } - __delete_object(object); +out: + if (object_l) + mem_pool_free(object_l); + if (object_r) + mem_pool_free(object_r); } static void __paint_it(struct kmemleak_object *object, int color) @@ -744,11 +921,11 @@ 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, unsigned int objflags) { struct kmemleak_object *object; - object = find_and_get_object(ptr, 0); + object = __find_and_get_object(ptr, 0, objflags); if (!object) { kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n", ptr, @@ -766,16 +943,38 @@ 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, 0); } /* * 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, unsigned int objflags) { - paint_ptr(ptr, KMEMLEAK_BLACK); + paint_ptr(ptr, KMEMLEAK_BLACK, objflags); +} + +/* + * Reset the checksum of an object. The immediate effect is that it will not + * be reported as a leak during the next scan until its checksum is updated. + */ +static void reset_checksum(unsigned long ptr) +{ + unsigned long flags; + struct kmemleak_object *object; + + object = find_and_get_object(ptr, 0); + if (!object) { + kmemleak_warn("Not resetting the checksum of an unknown object at 0x%08lx\n", + ptr); + return; + } + + raw_spin_lock_irqsave(&object->lock, flags); + object->checksum = 0; + raw_spin_unlock_irqrestore(&object->lock, flags); + put_object(object); } /* @@ -787,6 +986,8 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) unsigned long flags; struct kmemleak_object *object; struct kmemleak_scan_area *area = NULL; + unsigned long untagged_ptr; + unsigned long untagged_objp; object = find_and_get_object(ptr, 1); if (!object) { @@ -795,8 +996,12 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) return; } + untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); + untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer); + if (scan_area_cache) - area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); + area = kmem_cache_alloc_noprof(scan_area_cache, + gfp_nested_mask(gfp)); raw_spin_lock_irqsave(&object->lock, flags); if (!area) { @@ -806,8 +1011,8 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) goto out_unlock; } if (size == SIZE_MAX) { - size = object->pointer + object->size - ptr; - } else if (ptr + size > object->pointer + object->size) { + size = untagged_objp + object->size - untagged_ptr; + } else if (untagged_ptr + size > untagged_objp + object->size) { kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr); dump_object_info(object); kmem_cache_free(scan_area_cache, area); @@ -849,7 +1054,7 @@ static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref) } /* - * Set the OBJECT_NO_SCAN flag for the object corresponding to the give + * Set the OBJECT_NO_SCAN flag for the object corresponding to the given * pointer. Such object will not be scanned by kmemleak but references to it * are searched. */ @@ -887,7 +1092,7 @@ static void object_no_scan(unsigned long ptr) void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, gfp_t gfp) { - pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count); + pr_debug("%s(0x%px, %zu, %d)\n", __func__, ptr, size, min_count); if (kmemleak_enabled && ptr && !IS_ERR(ptr)) create_object((unsigned long)ptr, size, min_count, gfp); @@ -906,18 +1111,10 @@ EXPORT_SYMBOL_GPL(kmemleak_alloc); void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size, gfp_t gfp) { - unsigned int cpu; - - pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size); + pr_debug("%s(0x%px, %zu)\n", __func__, ptr, size); - /* - * Percpu allocations are only scanned and not reported as leaks - * (min_count is set to 0). - */ - if (kmemleak_enabled && ptr && !IS_ERR(ptr)) - for_each_possible_cpu(cpu) - create_object((unsigned long)per_cpu_ptr(ptr, cpu), - size, 0, gfp); + if (kmemleak_enabled && ptr && !IS_ERR_PCPU(ptr)) + create_object_percpu((__force unsigned long)ptr, size, 1, gfp); } EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); @@ -932,7 +1129,7 @@ EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); */ void __ref kmemleak_vmalloc(const struct vm_struct *area, size_t size, gfp_t gfp) { - pr_debug("%s(0x%p, %zu)\n", __func__, area, size); + pr_debug("%s(0x%px, %zu)\n", __func__, area, size); /* * A min_count = 2 is needed because vm_struct contains a reference to @@ -955,10 +1152,10 @@ EXPORT_SYMBOL_GPL(kmemleak_vmalloc); */ void __ref kmemleak_free(const void *ptr) { - pr_debug("%s(0x%p)\n", __func__, ptr); + pr_debug("%s(0x%px)\n", __func__, ptr); if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) - delete_object_full((unsigned long)ptr); + delete_object_full((unsigned long)ptr, 0); } EXPORT_SYMBOL_GPL(kmemleak_free); @@ -973,10 +1170,10 @@ EXPORT_SYMBOL_GPL(kmemleak_free); */ void __ref kmemleak_free_part(const void *ptr, size_t size) { - pr_debug("%s(0x%p)\n", __func__, ptr); + pr_debug("%s(0x%px)\n", __func__, ptr); if (kmemleak_enabled && ptr && !IS_ERR(ptr)) - delete_object_part((unsigned long)ptr, size); + delete_object_part((unsigned long)ptr, size, 0); } EXPORT_SYMBOL_GPL(kmemleak_free_part); @@ -989,14 +1186,10 @@ EXPORT_SYMBOL_GPL(kmemleak_free_part); */ void __ref kmemleak_free_percpu(const void __percpu *ptr) { - unsigned int cpu; - - pr_debug("%s(0x%p)\n", __func__, ptr); + pr_debug("%s(0x%px)\n", __func__, ptr); - if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) - for_each_possible_cpu(cpu) - delete_object_full((unsigned long)per_cpu_ptr(ptr, - cpu)); + if (kmemleak_free_enabled && ptr && !IS_ERR_PCPU(ptr)) + delete_object_full((__force unsigned long)ptr, OBJECT_PERCPU); } EXPORT_SYMBOL_GPL(kmemleak_free_percpu); @@ -1010,9 +1203,10 @@ EXPORT_SYMBOL_GPL(kmemleak_free_percpu); void __ref kmemleak_update_trace(const void *ptr) { struct kmemleak_object *object; + depot_stack_handle_t trace_handle; unsigned long flags; - pr_debug("%s(0x%p)\n", __func__, ptr); + pr_debug("%s(0x%px)\n", __func__, ptr); if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr)) return; @@ -1026,8 +1220,9 @@ void __ref kmemleak_update_trace(const void *ptr) return; } + trace_handle = set_track_prepare(); raw_spin_lock_irqsave(&object->lock, flags); - object->trace_len = __save_stack_trace(object->trace); + object->trace_handle = trace_handle; raw_spin_unlock_irqrestore(&object->lock, flags); put_object(object); @@ -1043,7 +1238,7 @@ EXPORT_SYMBOL(kmemleak_update_trace); */ void __ref kmemleak_not_leak(const void *ptr) { - pr_debug("%s(0x%p)\n", __func__, ptr); + pr_debug("%s(0x%px)\n", __func__, ptr); if (kmemleak_enabled && ptr && !IS_ERR(ptr)) make_gray_object((unsigned long)ptr); @@ -1051,6 +1246,37 @@ void __ref kmemleak_not_leak(const void *ptr) EXPORT_SYMBOL(kmemleak_not_leak); /** + * kmemleak_transient_leak - mark an allocated object as transient false positive + * @ptr: pointer to beginning of the object + * + * Calling this function on an object will cause the memory block to not be + * reported as a leak temporarily. This may happen, for example, if the object + * is part of a singly linked list and the ->next reference to it is changed. + */ +void __ref kmemleak_transient_leak(const void *ptr) +{ + pr_debug("%s(0x%px)\n", __func__, ptr); + + if (kmemleak_enabled && ptr && !IS_ERR(ptr)) + reset_checksum((unsigned long)ptr); +} +EXPORT_SYMBOL(kmemleak_transient_leak); + +/** + * kmemleak_ignore_percpu - similar to kmemleak_ignore but taking a percpu + * address argument + * @ptr: percpu address of the object + */ +void __ref kmemleak_ignore_percpu(const void __percpu *ptr) +{ + pr_debug("%s(0x%px)\n", __func__, ptr); + + if (kmemleak_enabled && ptr && !IS_ERR_PCPU(ptr)) + make_black_object((unsigned long)ptr, OBJECT_PERCPU); +} +EXPORT_SYMBOL_GPL(kmemleak_ignore_percpu); + +/** * kmemleak_ignore - ignore an allocated object * @ptr: pointer to beginning of the object * @@ -1061,10 +1287,10 @@ EXPORT_SYMBOL(kmemleak_not_leak); */ void __ref kmemleak_ignore(const void *ptr) { - pr_debug("%s(0x%p)\n", __func__, ptr); + pr_debug("%s(0x%px)\n", __func__, ptr); if (kmemleak_enabled && ptr && !IS_ERR(ptr)) - make_black_object((unsigned long)ptr); + make_black_object((unsigned long)ptr, 0); } EXPORT_SYMBOL(kmemleak_ignore); @@ -1081,7 +1307,7 @@ EXPORT_SYMBOL(kmemleak_ignore); */ void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) { - pr_debug("%s(0x%p)\n", __func__, ptr); + pr_debug("%s(0x%px)\n", __func__, ptr); if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) add_scan_area((unsigned long)ptr, size, gfp); @@ -1099,7 +1325,7 @@ EXPORT_SYMBOL(kmemleak_scan_area); */ void __ref kmemleak_no_scan(const void *ptr) { - pr_debug("%s(0x%p)\n", __func__, ptr); + pr_debug("%s(0x%px)\n", __func__, ptr); if (kmemleak_enabled && ptr && !IS_ERR(ptr)) object_no_scan((unsigned long)ptr); @@ -1111,15 +1337,18 @@ 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 (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn) - kmemleak_alloc(__va(phys), size, min_count, gfp); + pr_debug("%s(0x%px, %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); @@ -1132,22 +1361,12 @@ EXPORT_SYMBOL(kmemleak_alloc_phys); */ void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size) { - if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn) - kmemleak_free_part(__va(phys), size); -} -EXPORT_SYMBOL(kmemleak_free_part_phys); + pr_debug("%s(0x%px)\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 (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn) - kmemleak_not_leak(__va(phys)); + if (kmemleak_enabled) + delete_object_part((unsigned long)phys, size, OBJECT_PHYS); } -EXPORT_SYMBOL(kmemleak_not_leak_phys); +EXPORT_SYMBOL(kmemleak_free_part_phys); /** * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical @@ -1156,8 +1375,10 @@ EXPORT_SYMBOL(kmemleak_not_leak_phys); */ void __ref kmemleak_ignore_phys(phys_addr_t phys) { - if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn) - kmemleak_ignore(__va(phys)); + pr_debug("%s(0x%px)\n", __func__, &phys); + + if (kmemleak_enabled) + make_black_object((unsigned long)phys, OBJECT_PHYS); } EXPORT_SYMBOL(kmemleak_ignore_phys); @@ -1168,9 +1389,25 @@ 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(); - object->checksum = crc32(0, (void *)object->pointer, object->size); + kcsan_disable_current(); + if (object->flags & OBJECT_PERCPU) { + unsigned int cpu; + + object->checksum = 0; + for_each_possible_cpu(cpu) { + void *ptr = per_cpu_ptr((void __percpu *)object->pointer, cpu); + + object->checksum ^= crc32(0, kasan_reset_tag((void *)ptr), object->size); + } + } else { + object->checksum = crc32(0, kasan_reset_tag((void *)object->pointer), object->size); + } kasan_enable_current(); + kcsan_enable_current(); return object->checksum != old_csum; } @@ -1199,8 +1436,66 @@ static void update_refs(struct kmemleak_object *object) } } +static void pointer_update_refs(struct kmemleak_object *scanned, + unsigned long pointer, unsigned int objflags) +{ + struct kmemleak_object *object; + unsigned long untagged_ptr; + unsigned long excess_ref; + + untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer); + if (objflags & OBJECT_PERCPU) { + if (untagged_ptr < min_percpu_addr || untagged_ptr >= max_percpu_addr) + return; + } else { + if (untagged_ptr < min_addr || untagged_ptr >= max_addr) + return; + } + + /* + * No need for get_object() here since we hold kmemleak_lock. + * object->use_count cannot be dropped to 0 while the object + * is still present in object_tree_root and object_list + * (with updates protected by kmemleak_lock). + */ + object = __lookup_object(pointer, 1, objflags); + if (!object) + return; + if (object == scanned) + /* self referenced, ignore */ + return; + + /* + * Avoid the lockdep recursive warning on object->lock being + * previously acquired in scan_object(). These locks are + * enclosed by scan_mutex. + */ + raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); + /* only pass surplus references (object already gray) */ + if (color_gray(object)) { + excess_ref = object->excess_ref; + /* no need for update_refs() if object already gray */ + } else { + excess_ref = 0; + update_refs(object); + } + raw_spin_unlock(&object->lock); + + if (excess_ref) { + object = lookup_object(excess_ref, 0); + if (!object) + return; + if (object == scanned) + /* circular reference, ignore */ + return; + raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); + update_refs(object); + raw_spin_unlock(&object->lock); + } +} + /* - * Memory scanning is a long process and it needs to be interruptable. This + * Memory scanning is a long process and it needs to be interruptible. This * function checks whether such interrupt condition occurred. */ static int scan_should_stop(void) @@ -1231,65 +1526,20 @@ static void scan_block(void *_start, void *_end, unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); unsigned long *end = _end - (BYTES_PER_POINTER - 1); unsigned long flags; - unsigned long untagged_ptr; raw_spin_lock_irqsave(&kmemleak_lock, flags); for (ptr = start; ptr < end; ptr++) { - struct kmemleak_object *object; unsigned long pointer; - unsigned long excess_ref; if (scan_should_stop()) break; kasan_disable_current(); - pointer = *ptr; + pointer = *(unsigned long *)kasan_reset_tag((void *)ptr); kasan_enable_current(); - untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer); - if (untagged_ptr < min_addr || untagged_ptr >= max_addr) - continue; - - /* - * No need for get_object() here since we hold kmemleak_lock. - * object->use_count cannot be dropped to 0 while the object - * is still present in object_tree_root and object_list - * (with updates protected by kmemleak_lock). - */ - object = lookup_object(pointer, 1); - if (!object) - continue; - if (object == scanned) - /* self referenced, ignore */ - continue; - - /* - * Avoid the lockdep recursive warning on object->lock being - * previously acquired in scan_object(). These locks are - * enclosed by scan_mutex. - */ - raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); - /* only pass surplus references (object already gray) */ - if (color_gray(object)) { - excess_ref = object->excess_ref; - /* no need for update_refs() if object already gray */ - } else { - excess_ref = 0; - update_refs(object); - } - raw_spin_unlock(&object->lock); - - if (excess_ref) { - object = lookup_object(excess_ref, 0); - if (!object) - continue; - if (object == scanned) - /* circular reference, ignore */ - continue; - raw_spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); - update_refs(object); - raw_spin_unlock(&object->lock); - } + pointer_update_refs(scanned, pointer, 0); + pointer_update_refs(scanned, pointer, OBJECT_PERCPU); } raw_spin_unlock_irqrestore(&kmemleak_lock, flags); } @@ -1330,10 +1580,28 @@ static void scan_object(struct kmemleak_object *object) if (!(object->flags & OBJECT_ALLOCATED)) /* already freed object */ goto out; - if (hlist_empty(&object->area_list) || + + if (object->flags & OBJECT_PERCPU) { + unsigned int cpu; + + for_each_possible_cpu(cpu) { + void *start = per_cpu_ptr((void __percpu *)object->pointer, cpu); + void *end = start + object->size; + + scan_block(start, end, object); + + raw_spin_unlock_irqrestore(&object->lock, flags); + cond_resched(); + raw_spin_lock_irqsave(&object->lock, flags); + if (!(object->flags & OBJECT_ALLOCATED)) + break; + } + } else 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 = object->flags & OBJECT_PHYS ? + __va((phys_addr_t)object->pointer) : + (void *)object->pointer; + void *end = start + object->size; void *next; do { @@ -1348,11 +1616,12 @@ static void scan_object(struct kmemleak_object *object) cond_resched(); raw_spin_lock_irqsave(&object->lock, flags); } while (object->flags & OBJECT_ALLOCATED); - } else + } else { hlist_for_each_entry(area, &object->area_list, node) scan_block((void *)area->start, (void *)(area->start + area->size), object); + } out: raw_spin_unlock_irqrestore(&object->lock, flags); } @@ -1391,15 +1660,44 @@ static void scan_gray_list(void) } /* + * Conditionally call resched() in an object iteration loop while making sure + * that the given object won't go away without RCU read lock by performing a + * get_object() if necessaary. + */ +static void kmemleak_cond_resched(struct kmemleak_object *object) +{ + if (!get_object(object)) + return; /* Try next object */ + + raw_spin_lock_irq(&kmemleak_lock); + if (object->del_state & DELSTATE_REMOVED) + goto unlock_put; /* Object removed */ + object->del_state |= DELSTATE_NO_DELETE; + raw_spin_unlock_irq(&kmemleak_lock); + + rcu_read_unlock(); + cond_resched(); + rcu_read_lock(); + + raw_spin_lock_irq(&kmemleak_lock); + if (object->del_state & DELSTATE_REMOVED) + list_del_rcu(&object->object_list); + object->del_state &= ~DELSTATE_NO_DELETE; +unlock_put: + raw_spin_unlock_irq(&kmemleak_lock); + put_object(object); +} + +/* * Scan data sections and all the referenced memory blocks allocated via the * kernel's standard allocators. This function must be called with the * scan_mutex held. */ static void kmemleak_scan(void) { - unsigned long flags; struct kmemleak_object *object; - int i; + struct zone *zone; + int __maybe_unused i; int new_leaks = 0; jiffies_last_scan = jiffies; @@ -1407,7 +1705,7 @@ static void kmemleak_scan(void) /* 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); + raw_spin_lock_irq(&object->lock); #ifdef DEBUG /* * With a few exceptions there should be a maximum of @@ -1419,12 +1717,26 @@ 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)) list_add_tail(&object->gray_list, &gray_list); - raw_spin_unlock_irqrestore(&object->lock, flags); + raw_spin_unlock_irq(&object->lock); + + if (need_resched()) + kmemleak_cond_resched(object); } rcu_read_unlock(); @@ -1439,26 +1751,27 @@ static void kmemleak_scan(void) * Struct page scanning for each node. */ get_online_mems(); - for_each_online_node(i) { - unsigned long start_pfn = node_start_pfn(i); - unsigned long end_pfn = node_end_pfn(i); + for_each_populated_zone(zone) { + unsigned long start_pfn = zone->zone_start_pfn; + unsigned long end_pfn = zone_end_pfn(zone); unsigned long pfn; for (pfn = start_pfn; pfn < end_pfn; pfn++) { struct page *page = pfn_to_online_page(pfn); + if (!(pfn & 63)) + cond_resched(); + if (!page) continue; - /* only scan pages belonging to this node */ - if (page_to_nid(page) != i) + /* only scan pages belonging to this zone */ + if (page_zone(page) != zone) continue; /* only scan if page is in use */ if (page_count(page) == 0) continue; scan_block(page, page + 1, NULL); - if (!(pfn & 63)) - cond_resched(); } } put_online_mems(); @@ -1469,15 +1782,15 @@ static void kmemleak_scan(void) if (kmemleak_stack_scan) { struct task_struct *p, *g; - read_lock(&tasklist_lock); - do_each_thread(g, p) { + rcu_read_lock(); + for_each_process_thread(g, p) { void *stack = try_get_task_stack(p); if (stack) { scan_block(stack, stack + THREAD_SIZE, NULL); put_task_stack(p); } - } while_each_thread(g, p); - read_unlock(&tasklist_lock); + } + rcu_read_unlock(); } /* @@ -1492,14 +1805,24 @@ 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); + if (need_resched()) + kmemleak_cond_resched(object); + + /* + * 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(); @@ -1519,7 +1842,17 @@ 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); + if (need_resched()) + kmemleak_cond_resched(object); + + /* + * 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; @@ -1529,7 +1862,7 @@ static void kmemleak_scan(void) new_leaks++; } - raw_spin_unlock_irqrestore(&object->lock, flags); + raw_spin_unlock_irq(&object->lock); } rcu_read_unlock(); @@ -1557,14 +1890,14 @@ static int kmemleak_scan_thread(void *arg) * Wait before the first scan to allow the system to fully initialize. */ if (first_run) { - signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000); + signed long timeout = secs_to_jiffies(SECS_FIRST_SCAN); first_run = 0; while (timeout && !kthread_should_stop()) timeout = schedule_timeout_interruptible(timeout); } while (!kthread_should_stop()) { - signed long timeout = jiffies_scan_wait; + signed long timeout = READ_ONCE(jiffies_scan_wait); mutex_lock(&scan_mutex); kmemleak_scan(); @@ -1700,25 +2033,41 @@ static int kmemleak_open(struct inode *inode, struct file *file) return seq_open(file, &kmemleak_seq_ops); } -static int dump_str_object_info(const char *str) +static bool __dump_str_object_info(unsigned long addr, unsigned int objflags) { unsigned long flags; struct kmemleak_object *object; + + object = __find_and_get_object(addr, 1, objflags); + if (!object) + return false; + + raw_spin_lock_irqsave(&object->lock, flags); + dump_object_info(object); + raw_spin_unlock_irqrestore(&object->lock, flags); + + put_object(object); + + return true; +} + +static int dump_str_object_info(const char *str) +{ unsigned long addr; + bool found = false; if (kstrtoul(str, 0, &addr)) return -EINVAL; - object = find_and_get_object(addr, 0); - if (!object) { + + found |= __dump_str_object_info(addr, 0); + found |= __dump_str_object_info(addr, OBJECT_PHYS); + found |= __dump_str_object_info(addr, OBJECT_PERCPU); + + if (!found) { pr_info("Unknown object at 0x%08lx\n", addr); return -EINVAL; } - raw_spin_lock_irqsave(&object->lock, flags); - dump_object_info(object); - raw_spin_unlock_irqrestore(&object->lock, flags); - - put_object(object); return 0; } @@ -1731,15 +2080,14 @@ 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(); @@ -1804,14 +2152,20 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, else if (strncmp(buf, "scan=off", 8) == 0) stop_scan_thread(); else if (strncmp(buf, "scan=", 5) == 0) { - unsigned long secs; + unsigned secs; + unsigned long msecs; - ret = kstrtoul(buf + 5, 0, &secs); + ret = kstrtouint(buf + 5, 0, &secs); if (ret < 0) goto out; + + msecs = secs * MSEC_PER_SEC; + if (msecs > UINT_MAX) + msecs = UINT_MAX; + stop_scan_thread(); - if (secs) { - jiffies_scan_wait = msecs_to_jiffies(secs * 1000); + if (msecs) { + WRITE_ONCE(jiffies_scan_wait, msecs_to_jiffies(msecs)); start_scan_thread(); } } else if (strncmp(buf, "scan", 4) == 0) @@ -1843,6 +2197,7 @@ static const struct file_operations kmemleak_fops = { static void __kmemleak_do_cleanup(void) { struct kmemleak_object *object, *tmp; + unsigned int cnt = 0; /* * Kmemleak has already been disabled, no need for RCU list traversal @@ -1851,6 +2206,10 @@ static void __kmemleak_do_cleanup(void) list_for_each_entry_safe(object, tmp, &object_list, object_list) { __remove_object(object); __delete_object(object); + + /* Call cond_resched() once per 64 iterations to avoid soft lockup */ + if (!(++cnt & 0x3f)) + cond_resched(); } } @@ -1895,7 +2254,7 @@ static void kmemleak_disable(void) kmemleak_enabled = 0; /* check whether it is too early for a kernel thread */ - if (kmemleak_initialized) + if (kmemleak_late_initialized) schedule_work(&cleanup_work); else kmemleak_free_enabled = 0; @@ -1912,8 +2271,10 @@ static int __init kmemleak_boot_config(char *str) return -EINVAL; if (strcmp(str, "off") == 0) kmemleak_disable(); - else if (strcmp(str, "on") == 0) + else if (strcmp(str, "on") == 0) { kmemleak_skip_disable = 1; + stack_depot_request_early_init(); + } else return -EINVAL; return 0; @@ -1936,7 +2297,7 @@ void __init kmemleak_init(void) return; jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); - jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); + jiffies_scan_wait = secs_to_jiffies(SECS_SCAN_WAIT); object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE); scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE); @@ -1958,7 +2319,7 @@ void __init kmemleak_init(void) */ static int __init kmemleak_late_init(void) { - kmemleak_initialized = 1; + kmemleak_late_initialized = 1; debugfs_create_file("kmemleak", 0644, NULL, NULL, &kmemleak_fops); @@ -1966,7 +2327,7 @@ static int __init kmemleak_late_init(void) /* * Some error occurred and kmemleak was disabled. There is a * small chance that kmemleak_disable() was called immediately - * after setting kmemleak_initialized and we may end up with + * after setting kmemleak_late_initialized and we may end up with * two clean-up threads but serialized by scan_mutex. */ schedule_work(&cleanup_work); |