v4.19.13 snapshot.
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
new file mode 100644
index 0000000..17dd883
--- /dev/null
+++ b/mm/kmemleak.c
@@ -0,0 +1,2124 @@
+/*
+ * mm/kmemleak.c
+ *
+ * Copyright (C) 2008 ARM Limited
+ * Written by Catalin Marinas <catalin.marinas@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ *
+ * For more information on the algorithm and kmemleak usage, please see
+ * Documentation/dev-tools/kmemleak.rst.
+ *
+ * Notes on locking
+ * ----------------
+ *
+ * The following locks and mutexes are used by kmemleak:
+ *
+ * - kmemleak_lock (rwlock): 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_object.lock (spinlock): 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 (atomic or
+ * kmemleak_lock). This lock is also held when scanning the corresponding
+ * memory block to avoid the kernel freeing it via the kmemleak_free()
+ * callback. This is less heavyweight than holding a global lock like
+ * kmemleak_lock during scanning
+ * - scan_mutex (mutex): ensures that only one thread may scan the memory for
+ * unreferenced objects at a time. The gray_list contains the objects which
+ * are already referenced or marked as false positives and need to be
+ * scanned. This list is only modified during a scanning episode when the
+ * scan_mutex is held. At the end of a scan, the gray_list is always empty.
+ * Note that the kmemleak_object.use_count is incremented when an object is
+ * added to the gray_list and therefore cannot be freed. This mutex also
+ * prevents multiple users of the "kmemleak" debugfs file together with
+ * modifications to the memory scanning parameters including the scan_thread
+ * pointer
+ *
+ * Locks and mutexes are acquired/nested in the following order:
+ *
+ * scan_mutex [-> object->lock] -> kmemleak_lock -> other_object->lock (SINGLE_DEPTH_NESTING)
+ *
+ * No kmemleak_lock and object->lock nesting is allowed outside scan_mutex
+ * regions.
+ *
+ * The kmemleak_object structures have a use_count incremented or decremented
+ * using the get_object()/put_object() functions. When the use_count becomes
+ * 0, this count can no longer be incremented and put_object() schedules the
+ * kmemleak_object freeing via an RCU callback. All calls to the get_object()
+ * function must be protected by rcu_read_lock() to avoid accessing a freed
+ * structure.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/kthread.h>
+#include <linux/rbtree.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/cpumask.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/rcupdate.h>
+#include <linux/stacktrace.h>
+#include <linux/cache.h>
+#include <linux/percpu.h>
+#include <linux/bootmem.h>
+#include <linux/pfn.h>
+#include <linux/mmzone.h>
+#include <linux/slab.h>
+#include <linux/thread_info.h>
+#include <linux/err.h>
+#include <linux/uaccess.h>
+#include <linux/string.h>
+#include <linux/nodemask.h>
+#include <linux/mm.h>
+#include <linux/workqueue.h>
+#include <linux/crc32.h>
+
+#include <asm/sections.h>
+#include <asm/processor.h>
+#include <linux/atomic.h>
+
+#include <linux/kasan.h>
+#include <linux/kmemleak.h>
+#include <linux/memory_hotplug.h>
+
+/*
+ * Kmemleak configuration and common defines.
+ */
+#define MAX_TRACE 16 /* stack trace length */
+#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
+#define SECS_FIRST_SCAN 60 /* delay before the first scan */
+#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
+#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
+
+#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 | __GFP_NOFAIL)
+
+/* scanning area inside a memory block */
+struct kmemleak_scan_area {
+ struct hlist_node node;
+ unsigned long start;
+ size_t size;
+};
+
+#define KMEMLEAK_GREY 0
+#define KMEMLEAK_BLACK -1
+
+/*
+ * Structure holding the metadata for each allocated memory block.
+ * Modifications to such objects should be made while holding the
+ * object->lock. Insertions or deletions from object_list, gray_list or
+ * rb_node are already protected by the corresponding locks or mutex (see
+ * the notes on locking above). These objects are reference-counted
+ * (use_count) and freed using the RCU mechanism.
+ */
+struct kmemleak_object {
+ spinlock_t lock;
+ unsigned int flags; /* object status flags */
+ struct list_head object_list;
+ struct list_head gray_list;
+ struct rb_node rb_node;
+ struct rcu_head rcu; /* object_list lockless traversal */
+ /* object usage count; object freed when use_count == 0 */
+ atomic_t use_count;
+ unsigned long pointer;
+ size_t size;
+ /* pass surplus references to this pointer */
+ unsigned long excess_ref;
+ /* minimum number of a pointers found before it is considered leak */
+ int min_count;
+ /* the total number of pointers found pointing to this object */
+ int count;
+ /* checksum for detecting modified objects */
+ u32 checksum;
+ /* 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 */
+};
+
+/* flag representing the memory block allocation status */
+#define OBJECT_ALLOCATED (1 << 0)
+/* flag set after the first reporting of an unreference object */
+#define OBJECT_REPORTED (1 << 1)
+/* flag set to not scan the object */
+#define OBJECT_NO_SCAN (1 << 2)
+
+/* number of bytes to print per line; must be 16 or 32 */
+#define HEX_ROW_SIZE 16
+/* number of bytes to print at a time (1, 2, 4, 8) */
+#define HEX_GROUP_SIZE 1
+/* include ASCII after the hex output */
+#define HEX_ASCII 1
+/* max number of lines to be printed */
+#define HEX_MAX_LINES 2
+
+/* the list of all allocated objects */
+static LIST_HEAD(object_list);
+/* the list of gray-colored objects (see color_gray comment below) */
+static LIST_HEAD(gray_list);
+/* search tree for object boundaries */
+static struct rb_root object_tree_root = RB_ROOT;
+/* rw_lock protecting the access to object_list and object_tree_root */
+static DEFINE_RWLOCK(kmemleak_lock);
+
+/* allocation caches for kmemleak internal data */
+static struct kmem_cache *object_cache;
+static struct kmem_cache *scan_area_cache;
+
+/* set if tracing memory operations is enabled */
+static int kmemleak_enabled;
+/* same as above but only for the kmemleak_free() callback */
+static int kmemleak_free_enabled;
+/* set in the late_initcall if there were no errors */
+static int kmemleak_initialized;
+/* enables or disables early logging of the memory operations */
+static int kmemleak_early_log = 1;
+/* set if a kmemleak warning was issued */
+static int kmemleak_warning;
+/* set if a fatal kmemleak error has occurred */
+static int kmemleak_error;
+
+/* minimum and maximum address that may be valid pointers */
+static unsigned long min_addr = ULONG_MAX;
+static unsigned long max_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;
+/* enables or disables the task stacks scanning */
+static int kmemleak_stack_scan = 1;
+/* protects the memory scanning, parameters and debug/kmemleak file access */
+static DEFINE_MUTEX(scan_mutex);
+/* setting kmemleak=on, will set this var, skipping the disable */
+static int kmemleak_skip_disable;
+/* If there are leaks that can be reported */
+static bool kmemleak_found_leaks;
+
+/*
+ * Early object allocation/freeing logging. Kmemleak is initialized after the
+ * kernel allocator. However, both the kernel allocator and kmemleak may
+ * allocate memory blocks which need to be tracked. Kmemleak defines an
+ * arbitrary buffer to hold the allocation/freeing information before it is
+ * fully initialized.
+ */
+
+/* kmemleak operation type for early logging */
+enum {
+ KMEMLEAK_ALLOC,
+ KMEMLEAK_ALLOC_PERCPU,
+ KMEMLEAK_FREE,
+ KMEMLEAK_FREE_PART,
+ KMEMLEAK_FREE_PERCPU,
+ KMEMLEAK_NOT_LEAK,
+ KMEMLEAK_IGNORE,
+ KMEMLEAK_SCAN_AREA,
+ KMEMLEAK_NO_SCAN,
+ KMEMLEAK_SET_EXCESS_REF
+};
+
+/*
+ * Structure holding the information passed to kmemleak callbacks during the
+ * early logging.
+ */
+struct early_log {
+ int op_type; /* kmemleak operation type */
+ int min_count; /* minimum reference count */
+ const void *ptr; /* allocated/freed memory block */
+ union {
+ size_t size; /* memory block size */
+ unsigned long excess_ref; /* surplus reference passing */
+ };
+ unsigned long trace[MAX_TRACE]; /* stack trace */
+ unsigned int trace_len; /* stack trace length */
+};
+
+/* early logging buffer and current position */
+static struct early_log
+ early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE] __initdata;
+static int crt_early_log __initdata;
+
+static void kmemleak_disable(void);
+
+/*
+ * Print a warning and dump the stack trace.
+ */
+#define kmemleak_warn(x...) do { \
+ pr_warn(x); \
+ dump_stack(); \
+ kmemleak_warning = 1; \
+} while (0)
+
+/*
+ * Macro invoked when a serious kmemleak condition occurred and cannot be
+ * recovered from. Kmemleak will be disabled and further allocation/freeing
+ * tracing no longer available.
+ */
+#define kmemleak_stop(x...) do { \
+ kmemleak_warn(x); \
+ kmemleak_disable(); \
+} while (0)
+
+/*
+ * Printing of the objects hex dump to the seq file. The number of lines to be
+ * printed is limited to HEX_MAX_LINES to prevent seq file spamming. The
+ * actual number of printed bytes depends on HEX_ROW_SIZE. It must be called
+ * with the object->lock held.
+ */
+static void hex_dump_object(struct seq_file *seq,
+ struct kmemleak_object *object)
+{
+ const u8 *ptr = (const u8 *)object->pointer;
+ size_t len;
+
+ /* limit the number of lines to HEX_MAX_LINES */
+ len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE);
+
+ seq_printf(seq, " hex dump (first %zu bytes):\n", len);
+ kasan_disable_current();
+ seq_hex_dump(seq, " ", DUMP_PREFIX_NONE, HEX_ROW_SIZE,
+ HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
+ kasan_enable_current();
+}
+
+/*
+ * Object colors, encoded with count and min_count:
+ * - white - orphan object, not enough references to it (count < min_count)
+ * - gray - not orphan, not marked as false positive (min_count == 0) or
+ * 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)
+{
+ return object->count != KMEMLEAK_BLACK &&
+ object->count < object->min_count;
+}
+
+static bool color_gray(const struct kmemleak_object *object)
+{
+ return object->min_count != KMEMLEAK_BLACK &&
+ object->count >= object->min_count;
+}
+
+/*
+ * Objects are considered unreferenced only if their color is white, they have
+ * not be deleted and have a minimum age to avoid false positives caused by
+ * pointers temporarily stored in CPU registers.
+ */
+static bool unreferenced_object(struct kmemleak_object *object)
+{
+ return (color_white(object) && object->flags & OBJECT_ALLOCATED) &&
+ time_before_eq(object->jiffies + jiffies_min_age,
+ jiffies_last_scan);
+}
+
+/*
+ * Printing of the unreferenced objects information to the seq file. The
+ * print_unreferenced function must be called with the object->lock held.
+ */
+static void print_unreferenced(struct seq_file *seq,
+ struct kmemleak_object *object)
+{
+ int i;
+ unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
+
+ seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
+ object->pointer, object->size);
+ 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);
+ hex_dump_object(seq, object);
+ seq_printf(seq, " backtrace:\n");
+
+ for (i = 0; i < object->trace_len; i++) {
+ void *ptr = (void *)object->trace[i];
+ seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
+ }
+}
+
+/*
+ * Print the kmemleak_object information. This function is used mainly for
+ * debugging special cases when kmemleak operations. It must be called with
+ * the object->lock held.
+ */
+static void dump_object_info(struct kmemleak_object *object)
+{
+ struct stack_trace trace;
+
+ trace.nr_entries = object->trace_len;
+ trace.entries = object->trace;
+
+ pr_notice("Object 0x%08lx (size %zu):\n",
+ 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);
+ pr_notice(" count = %d\n", object->count);
+ pr_notice(" flags = 0x%x\n", object->flags);
+ pr_notice(" checksum = %u\n", object->checksum);
+ pr_notice(" backtrace:\n");
+ print_stack_trace(&trace, 4);
+}
+
+/*
+ * Look-up a memory block metadata (kmemleak_object) in the object search
+ * tree based on a pointer value. If alias is 0, only values pointing to the
+ * 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)
+{
+ struct rb_node *rb = object_tree_root.rb_node;
+
+ while (rb) {
+ struct kmemleak_object *object =
+ rb_entry(rb, struct kmemleak_object, rb_node);
+ if (ptr < object->pointer)
+ rb = object->rb_node.rb_left;
+ else if (object->pointer + object->size <= ptr)
+ rb = object->rb_node.rb_right;
+ else if (object->pointer == ptr || alias)
+ return object;
+ else {
+ kmemleak_warn("Found object by alias at 0x%08lx\n",
+ ptr);
+ dump_object_info(object);
+ break;
+ }
+ }
+ return NULL;
+}
+
+/*
+ * 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
+ * registered and the object should no longer be used. This function must be
+ * called under the protection of rcu_read_lock().
+ */
+static int get_object(struct kmemleak_object *object)
+{
+ return atomic_inc_not_zero(&object->use_count);
+}
+
+/*
+ * RCU callback to free a kmemleak_object.
+ */
+static void free_object_rcu(struct rcu_head *rcu)
+{
+ struct hlist_node *tmp;
+ struct kmemleak_scan_area *area;
+ struct kmemleak_object *object =
+ container_of(rcu, struct kmemleak_object, rcu);
+
+ /*
+ * Once use_count is 0 (guaranteed by put_object), there is no other
+ * code accessing this object, hence no need for locking.
+ */
+ hlist_for_each_entry_safe(area, tmp, &object->area_list, node) {
+ hlist_del(&area->node);
+ kmem_cache_free(scan_area_cache, area);
+ }
+ kmem_cache_free(object_cache, object);
+}
+
+/*
+ * Decrement the object use_count. Once the count is 0, free the object using
+ * an RCU callback. Since put_object() may be called via the kmemleak_free() ->
+ * delete_object() path, the delayed RCU freeing ensures that there is no
+ * recursive call to the kernel allocator. Lock-less RCU object_list traversal
+ * is also possible.
+ */
+static void put_object(struct kmemleak_object *object)
+{
+ if (!atomic_dec_and_test(&object->use_count))
+ return;
+
+ /* should only get here after delete_object was called */
+ WARN_ON(object->flags & OBJECT_ALLOCATED);
+
+ call_rcu(&object->rcu, free_object_rcu);
+}
+
+/*
+ * 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)
+{
+ unsigned long flags;
+ struct kmemleak_object *object;
+
+ rcu_read_lock();
+ read_lock_irqsave(&kmemleak_lock, flags);
+ object = lookup_object(ptr, alias);
+ read_unlock_irqrestore(&kmemleak_lock, flags);
+
+ /* check whether the object is still available */
+ if (object && !get_object(object))
+ object = NULL;
+ rcu_read_unlock();
+
+ 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().
+ */
+static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int alias)
+{
+ unsigned long flags;
+ struct kmemleak_object *object;
+
+ write_lock_irqsave(&kmemleak_lock, flags);
+ object = lookup_object(ptr, alias);
+ if (object) {
+ rb_erase(&object->rb_node, &object_tree_root);
+ list_del_rcu(&object->object_list);
+ }
+ write_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)
+{
+ struct stack_trace stack_trace;
+
+ stack_trace.max_entries = MAX_TRACE;
+ stack_trace.nr_entries = 0;
+ stack_trace.entries = trace;
+ stack_trace.skip = 2;
+ save_stack_trace(&stack_trace);
+
+ return stack_trace.nr_entries;
+}
+
+/*
+ * 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)
+{
+ unsigned long flags;
+ struct kmemleak_object *object, *parent;
+ struct rb_node **link, *rb_parent;
+
+ object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp));
+ if (!object) {
+ pr_warn("Cannot allocate a kmemleak_object structure\n");
+ kmemleak_disable();
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&object->object_list);
+ INIT_LIST_HEAD(&object->gray_list);
+ INIT_HLIST_HEAD(&object->area_list);
+ 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;
+
+ /* task information */
+ if (in_irq()) {
+ object->pid = 0;
+ strncpy(object->comm, "hardirq", sizeof(object->comm));
+ } else if (in_softirq()) {
+ object->pid = 0;
+ strncpy(object->comm, "softirq", sizeof(object->comm));
+ } else {
+ object->pid = current->pid;
+ /*
+ * There is a small chance of a race with set_task_comm(),
+ * however using get_task_comm() here may cause locking
+ * dependency issues with current->alloc_lock. In the worst
+ * case, the command line is not correct.
+ */
+ strncpy(object->comm, current->comm, sizeof(object->comm));
+ }
+
+ /* kernel backtrace */
+ object->trace_len = __save_stack_trace(object->trace);
+
+ write_lock_irqsave(&kmemleak_lock, flags);
+
+ min_addr = min(min_addr, ptr);
+ max_addr = max(max_addr, ptr + size);
+ link = &object_tree_root.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)
+ link = &parent->rb_node.rb_left;
+ else if (parent->pointer + parent->size <= ptr)
+ link = &parent->rb_node.rb_right;
+ else {
+ kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing)\n",
+ ptr);
+ /*
+ * No need for parent->lock here since "parent" cannot
+ * be freed while the kmemleak_lock is held.
+ */
+ dump_object_info(parent);
+ kmem_cache_free(object_cache, object);
+ object = NULL;
+ goto out;
+ }
+ }
+ rb_link_node(&object->rb_node, rb_parent, link);
+ rb_insert_color(&object->rb_node, &object_tree_root);
+
+ list_add_tail_rcu(&object->object_list, &object_list);
+out:
+ write_unlock_irqrestore(&kmemleak_lock, flags);
+ return object;
+}
+
+/*
+ * Mark the object as not allocated and schedule RCU freeing via put_object().
+ */
+static void __delete_object(struct kmemleak_object *object)
+{
+ unsigned long flags;
+
+ WARN_ON(!(object->flags & OBJECT_ALLOCATED));
+ WARN_ON(atomic_read(&object->use_count) < 1);
+
+ /*
+ * Locking here also ensures that the corresponding memory block
+ * cannot be freed when it is being scanned.
+ */
+ spin_lock_irqsave(&object->lock, flags);
+ object->flags &= ~OBJECT_ALLOCATED;
+ spin_unlock_irqrestore(&object->lock, flags);
+ put_object(object);
+}
+
+/*
+ * Look up the metadata (struct kmemleak_object) corresponding to ptr and
+ * delete it.
+ */
+static void delete_object_full(unsigned long ptr)
+{
+ struct kmemleak_object *object;
+
+ object = find_and_remove_object(ptr, 0);
+ if (!object) {
+#ifdef DEBUG
+ kmemleak_warn("Freeing unknown object at 0x%08lx\n",
+ ptr);
+#endif
+ return;
+ }
+ __delete_object(object);
+}
+
+/*
+ * Look up the metadata (struct kmemleak_object) corresponding to ptr and
+ * 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)
+{
+ struct kmemleak_object *object;
+ unsigned long start, end;
+
+ 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
+ return;
+ }
+
+ /*
+ * Create one or two objects that may result from the memory block
+ * split. Note that partial freeing is only done by free_bootmem() and
+ * this happens before kmemleak_init() is called. The path below is
+ * only executed during early log recording in kmemleak_init(), so
+ * GFP_KERNEL is enough.
+ */
+ 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);
+
+ __delete_object(object);
+}
+
+static void __paint_it(struct kmemleak_object *object, int color)
+{
+ object->min_count = color;
+ if (color == KMEMLEAK_BLACK)
+ object->flags |= OBJECT_NO_SCAN;
+}
+
+static void paint_it(struct kmemleak_object *object, int color)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&object->lock, flags);
+ __paint_it(object, color);
+ spin_unlock_irqrestore(&object->lock, flags);
+}
+
+static void paint_ptr(unsigned long ptr, int color)
+{
+ struct kmemleak_object *object;
+
+ object = find_and_get_object(ptr, 0);
+ if (!object) {
+ kmemleak_warn("Trying to color unknown object at 0x%08lx as %s\n",
+ ptr,
+ (color == KMEMLEAK_GREY) ? "Grey" :
+ (color == KMEMLEAK_BLACK) ? "Black" : "Unknown");
+ return;
+ }
+ paint_it(object, color);
+ put_object(object);
+}
+
+/*
+ * Mark an object permanently as gray-colored so that it can no longer be
+ * reported as a leak. This is used in general to mark a false positive.
+ */
+static void make_gray_object(unsigned long ptr)
+{
+ paint_ptr(ptr, KMEMLEAK_GREY);
+}
+
+/*
+ * Mark the object as black-colored so that it is ignored from scans and
+ * reporting.
+ */
+static void make_black_object(unsigned long ptr)
+{
+ paint_ptr(ptr, KMEMLEAK_BLACK);
+}
+
+/*
+ * Add a scanning area to the object. If at least one such area is added,
+ * kmemleak will only scan these ranges rather than the whole memory block.
+ */
+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;
+
+ object = find_and_get_object(ptr, 1);
+ if (!object) {
+ kmemleak_warn("Adding scan area to unknown object at 0x%08lx\n",
+ ptr);
+ return;
+ }
+
+ area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
+ if (!area) {
+ pr_warn("Cannot allocate a scan area\n");
+ goto out;
+ }
+
+ spin_lock_irqsave(&object->lock, flags);
+ if (size == SIZE_MAX) {
+ size = object->pointer + object->size - ptr;
+ } else if (ptr + size > object->pointer + object->size) {
+ kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
+ dump_object_info(object);
+ kmem_cache_free(scan_area_cache, area);
+ goto out_unlock;
+ }
+
+ INIT_HLIST_NODE(&area->node);
+ area->start = ptr;
+ area->size = size;
+
+ hlist_add_head(&area->node, &object->area_list);
+out_unlock:
+ spin_unlock_irqrestore(&object->lock, flags);
+out:
+ put_object(object);
+}
+
+/*
+ * Any surplus references (object already gray) to 'ptr' are passed to
+ * 'excess_ref'. This is used in the vmalloc() case where a pointer to
+ * vm_struct may be used as an alternative reference to the vmalloc'ed object
+ * (see free_thread_stack()).
+ */
+static void object_set_excess_ref(unsigned long ptr, unsigned long excess_ref)
+{
+ unsigned long flags;
+ struct kmemleak_object *object;
+
+ object = find_and_get_object(ptr, 0);
+ if (!object) {
+ kmemleak_warn("Setting excess_ref on unknown object at 0x%08lx\n",
+ ptr);
+ return;
+ }
+
+ spin_lock_irqsave(&object->lock, flags);
+ object->excess_ref = excess_ref;
+ spin_unlock_irqrestore(&object->lock, flags);
+ put_object(object);
+}
+
+/*
+ * Set the OBJECT_NO_SCAN flag for the object corresponding to the give
+ * pointer. Such object will not be scanned by kmemleak but references to it
+ * are searched.
+ */
+static void object_no_scan(unsigned long ptr)
+{
+ unsigned long flags;
+ struct kmemleak_object *object;
+
+ object = find_and_get_object(ptr, 0);
+ if (!object) {
+ kmemleak_warn("Not scanning unknown object at 0x%08lx\n", ptr);
+ return;
+ }
+
+ spin_lock_irqsave(&object->lock, flags);
+ object->flags |= OBJECT_NO_SCAN;
+ spin_unlock_irqrestore(&object->lock, flags);
+ put_object(object);
+}
+
+/*
+ * Log an early kmemleak_* call to the early_log buffer. These calls will be
+ * processed later once kmemleak is fully initialized.
+ */
+static void __init log_early(int op_type, const void *ptr, size_t size,
+ int min_count)
+{
+ unsigned long flags;
+ struct early_log *log;
+
+ if (kmemleak_error) {
+ /* kmemleak stopped recording, just count the requests */
+ crt_early_log++;
+ return;
+ }
+
+ if (crt_early_log >= ARRAY_SIZE(early_log)) {
+ crt_early_log++;
+ kmemleak_disable();
+ return;
+ }
+
+ /*
+ * There is no need for locking since the kernel is still in UP mode
+ * at this stage. Disabling the IRQs is enough.
+ */
+ local_irq_save(flags);
+ log = &early_log[crt_early_log];
+ log->op_type = op_type;
+ log->ptr = ptr;
+ log->size = size;
+ log->min_count = min_count;
+ log->trace_len = __save_stack_trace(log->trace);
+ crt_early_log++;
+ local_irq_restore(flags);
+}
+
+/*
+ * Log an early allocated block and populate the stack trace.
+ */
+static void early_alloc(struct early_log *log)
+{
+ struct kmemleak_object *object;
+ unsigned long flags;
+ int i;
+
+ if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
+ return;
+
+ /*
+ * RCU locking needed to ensure object is not freed via put_object().
+ */
+ rcu_read_lock();
+ object = create_object((unsigned long)log->ptr, log->size,
+ log->min_count, GFP_ATOMIC);
+ if (!object)
+ goto out;
+ spin_lock_irqsave(&object->lock, flags);
+ for (i = 0; i < log->trace_len; i++)
+ object->trace[i] = log->trace[i];
+ object->trace_len = log->trace_len;
+ spin_unlock_irqrestore(&object->lock, flags);
+out:
+ rcu_read_unlock();
+}
+
+/*
+ * Log an early allocated block and populate the stack trace.
+ */
+static void early_alloc_percpu(struct early_log *log)
+{
+ unsigned int cpu;
+ const void __percpu *ptr = log->ptr;
+
+ for_each_possible_cpu(cpu) {
+ log->ptr = per_cpu_ptr(ptr, cpu);
+ early_alloc(log);
+ }
+}
+
+/**
+ * kmemleak_alloc - register a newly allocated object
+ * @ptr: pointer to beginning of the object
+ * @size: size of the object
+ * @min_count: minimum number of references to this object. If during memory
+ * scanning a number of references less than @min_count is found,
+ * the object is reported as a memory leak. If @min_count is 0,
+ * the object is never reported as a leak. If @min_count is -1,
+ * the object is ignored (not scanned and not reported as a leak)
+ * @gfp: kmalloc() flags used for kmemleak internal memory allocations
+ *
+ * This function is called from the kernel allocators when a new object
+ * (memory block) is allocated (kmem_cache_alloc, kmalloc etc.).
+ */
+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);
+
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
+ create_object((unsigned long)ptr, size, min_count, gfp);
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
+}
+EXPORT_SYMBOL_GPL(kmemleak_alloc);
+
+/**
+ * kmemleak_alloc_percpu - register a newly allocated __percpu object
+ * @ptr: __percpu pointer to beginning of the object
+ * @size: size of the object
+ * @gfp: flags used for kmemleak internal memory allocations
+ *
+ * This function is called from the kernel percpu allocator when a new object
+ * (memory block) is allocated (alloc_percpu).
+ */
+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);
+
+ /*
+ * 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);
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
+}
+EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
+
+/**
+ * kmemleak_vmalloc - register a newly vmalloc'ed object
+ * @area: pointer to vm_struct
+ * @size: size of the object
+ * @gfp: __vmalloc() flags used for kmemleak internal memory allocations
+ *
+ * This function is called from the vmalloc() kernel allocator when a new
+ * object (memory block) is allocated.
+ */
+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);
+
+ /*
+ * A min_count = 2 is needed because vm_struct contains a reference to
+ * the virtual address of the vmalloc'ed block.
+ */
+ if (kmemleak_enabled) {
+ create_object((unsigned long)area->addr, size, 2, gfp);
+ object_set_excess_ref((unsigned long)area,
+ (unsigned long)area->addr);
+ } else if (kmemleak_early_log) {
+ log_early(KMEMLEAK_ALLOC, area->addr, size, 2);
+ /* reusing early_log.size for storing area->addr */
+ log_early(KMEMLEAK_SET_EXCESS_REF,
+ area, (unsigned long)area->addr, 0);
+ }
+}
+EXPORT_SYMBOL_GPL(kmemleak_vmalloc);
+
+/**
+ * kmemleak_free - unregister a previously registered object
+ * @ptr: pointer to beginning of the object
+ *
+ * This function is called from the kernel allocators when an object (memory
+ * block) is freed (kmem_cache_free, kfree, vfree etc.).
+ */
+void __ref kmemleak_free(const void *ptr)
+{
+ pr_debug("%s(0x%p)\n", __func__, ptr);
+
+ if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
+ delete_object_full((unsigned long)ptr);
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_FREE, ptr, 0, 0);
+}
+EXPORT_SYMBOL_GPL(kmemleak_free);
+
+/**
+ * kmemleak_free_part - partially unregister a previously registered object
+ * @ptr: pointer to the beginning or inside the object. This also
+ * represents the start of the range to be freed
+ * @size: size to be unregistered
+ *
+ * This function is called when only a part of a memory block is freed
+ * (usually from the bootmem allocator).
+ */
+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);
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
+}
+EXPORT_SYMBOL_GPL(kmemleak_free_part);
+
+/**
+ * kmemleak_free_percpu - unregister a previously registered __percpu object
+ * @ptr: __percpu pointer to beginning of the object
+ *
+ * This function is called from the kernel percpu allocator when an object
+ * (memory block) is freed (free_percpu).
+ */
+void __ref kmemleak_free_percpu(const void __percpu *ptr)
+{
+ unsigned int cpu;
+
+ pr_debug("%s(0x%p)\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));
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
+}
+EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
+
+/**
+ * kmemleak_update_trace - update object allocation stack trace
+ * @ptr: pointer to beginning of the object
+ *
+ * Override the object allocation stack trace for cases where the actual
+ * allocation place is not always useful.
+ */
+void __ref kmemleak_update_trace(const void *ptr)
+{
+ struct kmemleak_object *object;
+ unsigned long flags;
+
+ pr_debug("%s(0x%p)\n", __func__, ptr);
+
+ if (!kmemleak_enabled || IS_ERR_OR_NULL(ptr))
+ return;
+
+ object = find_and_get_object((unsigned long)ptr, 1);
+ if (!object) {
+#ifdef DEBUG
+ kmemleak_warn("Updating stack trace for unknown object at %p\n",
+ ptr);
+#endif
+ return;
+ }
+
+ spin_lock_irqsave(&object->lock, flags);
+ object->trace_len = __save_stack_trace(object->trace);
+ spin_unlock_irqrestore(&object->lock, flags);
+
+ put_object(object);
+}
+EXPORT_SYMBOL(kmemleak_update_trace);
+
+/**
+ * kmemleak_not_leak - mark an allocated object as false positive
+ * @ptr: pointer to beginning of the object
+ *
+ * Calling this function on an object will cause the memory block to no longer
+ * be reported as leak and always be scanned.
+ */
+void __ref kmemleak_not_leak(const void *ptr)
+{
+ pr_debug("%s(0x%p)\n", __func__, ptr);
+
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
+ make_gray_object((unsigned long)ptr);
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
+}
+EXPORT_SYMBOL(kmemleak_not_leak);
+
+/**
+ * kmemleak_ignore - ignore an allocated object
+ * @ptr: pointer to beginning of the object
+ *
+ * Calling this function on an object will cause the memory block to be
+ * ignored (not scanned and not reported as a leak). This is usually done when
+ * it is known that the corresponding block is not a leak and does not contain
+ * any references to other allocated memory blocks.
+ */
+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);
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
+}
+EXPORT_SYMBOL(kmemleak_ignore);
+
+/**
+ * kmemleak_scan_area - limit the range to be scanned in an allocated object
+ * @ptr: pointer to beginning or inside the object. This also
+ * represents the start of the scan area
+ * @size: size of the scan area
+ * @gfp: kmalloc() flags used for kmemleak internal memory allocations
+ *
+ * This function is used when it is known that only certain parts of an object
+ * contain references to other objects. Kmemleak will only scan these areas
+ * reducing the number false negatives.
+ */
+void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
+{
+ pr_debug("%s(0x%p)\n", __func__, ptr);
+
+ if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
+ add_scan_area((unsigned long)ptr, size, gfp);
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
+}
+EXPORT_SYMBOL(kmemleak_scan_area);
+
+/**
+ * kmemleak_no_scan - do not scan an allocated object
+ * @ptr: pointer to beginning of the object
+ *
+ * This function notifies kmemleak not to scan the given memory block. Useful
+ * in situations where it is known that the given object does not contain any
+ * references to other objects. Kmemleak will not scan such objects reducing
+ * the number of false negatives.
+ */
+void __ref kmemleak_no_scan(const void *ptr)
+{
+ pr_debug("%s(0x%p)\n", __func__, ptr);
+
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
+ object_no_scan((unsigned long)ptr);
+ else if (kmemleak_early_log)
+ log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
+}
+EXPORT_SYMBOL(kmemleak_no_scan);
+
+/**
+ * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical
+ * 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)
+{
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
+ kmemleak_alloc(__va(phys), size, min_count, gfp);
+}
+EXPORT_SYMBOL(kmemleak_alloc_phys);
+
+/**
+ * kmemleak_free_part_phys - similar to kmemleak_free_part but taking a
+ * physical address argument
+ * @phys: physical address if the beginning or inside an object. This
+ * also represents the start of the range to be freed
+ * @size: size to be unregistered
+ */
+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);
+
+/**
+ * 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));
+}
+EXPORT_SYMBOL(kmemleak_not_leak_phys);
+
+/**
+ * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
+ * address argument
+ * @phys: physical address of the object
+ */
+void __ref kmemleak_ignore_phys(phys_addr_t phys)
+{
+ if (!IS_ENABLED(CONFIG_HIGHMEM) || PHYS_PFN(phys) < max_low_pfn)
+ kmemleak_ignore(__va(phys));
+}
+EXPORT_SYMBOL(kmemleak_ignore_phys);
+
+/*
+ * Update an object's checksum and return true if it was modified.
+ */
+static bool update_checksum(struct kmemleak_object *object)
+{
+ u32 old_csum = object->checksum;
+
+ kasan_disable_current();
+ object->checksum = crc32(0, (void *)object->pointer, object->size);
+ kasan_enable_current();
+
+ return object->checksum != old_csum;
+}
+
+/*
+ * Update an object's references. object->lock must be held by the caller.
+ */
+static void update_refs(struct kmemleak_object *object)
+{
+ if (!color_white(object)) {
+ /* non-orphan, ignored or new */
+ return;
+ }
+
+ /*
+ * Increase the object's reference count (number of pointers to the
+ * memory block). If this count reaches the required minimum, the
+ * object's color will become gray and it will be added to the
+ * gray_list.
+ */
+ object->count++;
+ if (color_gray(object)) {
+ /* put_object() called when removing from gray_list */
+ WARN_ON(!get_object(object));
+ list_add_tail(&object->gray_list, &gray_list);
+ }
+}
+
+/*
+ * Memory scanning is a long process and it needs to be interruptable. This
+ * function checks whether such interrupt condition occurred.
+ */
+static int scan_should_stop(void)
+{
+ if (!kmemleak_enabled)
+ return 1;
+
+ /*
+ * This function may be called from either process or kthread context,
+ * hence the need to check for both stop conditions.
+ */
+ if (current->mm)
+ return signal_pending(current);
+ else
+ return kthread_should_stop();
+
+ return 0;
+}
+
+/*
+ * Scan a memory block (exclusive range) for valid pointers and add those
+ * found to the gray list.
+ */
+static void scan_block(void *_start, void *_end,
+ struct kmemleak_object *scanned)
+{
+ unsigned long *ptr;
+ unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER);
+ unsigned long *end = _end - (BYTES_PER_POINTER - 1);
+ unsigned long flags;
+
+ read_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;
+ kasan_enable_current();
+
+ if (pointer < min_addr || pointer >= 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.
+ */
+ 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);
+ }
+ spin_unlock(&object->lock);
+
+ if (excess_ref) {
+ object = lookup_object(excess_ref, 0);
+ if (!object)
+ continue;
+ if (object == scanned)
+ /* circular reference, ignore */
+ continue;
+ spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING);
+ update_refs(object);
+ spin_unlock(&object->lock);
+ }
+ }
+ read_unlock_irqrestore(&kmemleak_lock, flags);
+}
+
+/*
+ * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency.
+ */
+static void scan_large_block(void *start, void *end)
+{
+ void *next;
+
+ while (start < end) {
+ next = min(start + MAX_SCAN_SIZE, end);
+ scan_block(start, next, NULL);
+ start = next;
+ cond_resched();
+ }
+}
+
+/*
+ * Scan a memory block corresponding to a kmemleak_object. A condition is
+ * that object->use_count >= 1.
+ */
+static void scan_object(struct kmemleak_object *object)
+{
+ struct kmemleak_scan_area *area;
+ unsigned long flags;
+
+ /*
+ * Once the object->lock is acquired, the corresponding memory block
+ * cannot be freed (the same lock is acquired in delete_object).
+ */
+ spin_lock_irqsave(&object->lock, flags);
+ if (object->flags & OBJECT_NO_SCAN)
+ goto out;
+ if (!(object->flags & OBJECT_ALLOCATED))
+ /* already freed object */
+ goto out;
+ if (hlist_empty(&object->area_list)) {
+ void *start = (void *)object->pointer;
+ void *end = (void *)(object->pointer + object->size);
+ void *next;
+
+ do {
+ next = min(start + MAX_SCAN_SIZE, end);
+ scan_block(start, next, object);
+
+ start = next;
+ if (start >= end)
+ break;
+
+ spin_unlock_irqrestore(&object->lock, flags);
+ cond_resched();
+ spin_lock_irqsave(&object->lock, flags);
+ } while (object->flags & OBJECT_ALLOCATED);
+ } else
+ hlist_for_each_entry(area, &object->area_list, node)
+ scan_block((void *)area->start,
+ (void *)(area->start + area->size),
+ object);
+out:
+ spin_unlock_irqrestore(&object->lock, flags);
+}
+
+/*
+ * Scan the objects already referenced (gray objects). More objects will be
+ * referenced and, if there are no memory leaks, all the objects are scanned.
+ */
+static void scan_gray_list(void)
+{
+ struct kmemleak_object *object, *tmp;
+
+ /*
+ * The list traversal is safe for both tail additions and removals
+ * from inside the loop. The kmemleak objects cannot be freed from
+ * outside the loop because their use_count was incremented.
+ */
+ object = list_entry(gray_list.next, typeof(*object), gray_list);
+ while (&object->gray_list != &gray_list) {
+ cond_resched();
+
+ /* may add new objects to the list */
+ if (!scan_should_stop())
+ scan_object(object);
+
+ tmp = list_entry(object->gray_list.next, typeof(*object),
+ gray_list);
+
+ /* remove the object from the list and release it */
+ list_del(&object->gray_list);
+ put_object(object);
+
+ object = tmp;
+ }
+ WARN_ON(!list_empty(&gray_list));
+}
+
+/*
+ * 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;
+ int new_leaks = 0;
+
+ jiffies_last_scan = jiffies;
+
+ /* prepare the kmemleak_object's */
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list) {
+ spin_lock_irqsave(&object->lock, flags);
+#ifdef DEBUG
+ /*
+ * With a few exceptions there should be a maximum of
+ * 1 reference to any object at this point.
+ */
+ if (atomic_read(&object->use_count) > 1) {
+ pr_debug("object->use_count = %d\n",
+ atomic_read(&object->use_count));
+ dump_object_info(object);
+ }
+#endif
+ /* 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);
+
+ spin_unlock_irqrestore(&object->lock, flags);
+ }
+ rcu_read_unlock();
+
+ /* data/bss scanning */
+ scan_large_block(_sdata, _edata);
+ scan_large_block(__bss_start, __bss_stop);
+ scan_large_block(__start_ro_after_init, __end_ro_after_init);
+
+#ifdef CONFIG_SMP
+ /* per-cpu sections scanning */
+ for_each_possible_cpu(i)
+ scan_large_block(__per_cpu_start + per_cpu_offset(i),
+ __per_cpu_end + per_cpu_offset(i));
+#endif
+
+ /*
+ * 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);
+ unsigned long pfn;
+
+ for (pfn = start_pfn; pfn < end_pfn; pfn++) {
+ struct page *page;
+
+ if (!pfn_valid(pfn))
+ continue;
+ page = pfn_to_page(pfn);
+ /* 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();
+
+ /*
+ * Scanning the task stacks (may introduce false negatives).
+ */
+ if (kmemleak_stack_scan) {
+ struct task_struct *p, *g;
+
+ read_lock(&tasklist_lock);
+ do_each_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);
+ }
+
+ /*
+ * Scan the objects already referenced from the sections scanned
+ * above.
+ */
+ scan_gray_list();
+
+ /*
+ * Check for new or unreferenced objects modified since the previous
+ * scan and color them gray until the next scan.
+ */
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list) {
+ spin_lock_irqsave(&object->lock, flags);
+ 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);
+ }
+ spin_unlock_irqrestore(&object->lock, flags);
+ }
+ rcu_read_unlock();
+
+ /*
+ * Re-scan the gray list for modified unreferenced objects.
+ */
+ scan_gray_list();
+
+ /*
+ * If scanning was stopped do not report any new unreferenced objects.
+ */
+ if (scan_should_stop())
+ return;
+
+ /*
+ * Scanning result reporting.
+ */
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list) {
+ spin_lock_irqsave(&object->lock, flags);
+ if (unreferenced_object(object) &&
+ !(object->flags & OBJECT_REPORTED)) {
+ object->flags |= OBJECT_REPORTED;
+ new_leaks++;
+ }
+ spin_unlock_irqrestore(&object->lock, flags);
+ }
+ rcu_read_unlock();
+
+ if (new_leaks) {
+ kmemleak_found_leaks = true;
+
+ pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak)\n",
+ new_leaks);
+ }
+
+}
+
+/*
+ * Thread function performing automatic memory scanning. Unreferenced objects
+ * at the end of a memory scan are reported but only the first time.
+ */
+static int kmemleak_scan_thread(void *arg)
+{
+ static int first_run = 1;
+
+ pr_info("Automatic memory scanning thread started\n");
+ set_user_nice(current, 10);
+
+ /*
+ * 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);
+ first_run = 0;
+ while (timeout && !kthread_should_stop())
+ timeout = schedule_timeout_interruptible(timeout);
+ }
+
+ while (!kthread_should_stop()) {
+ signed long timeout = jiffies_scan_wait;
+
+ mutex_lock(&scan_mutex);
+ kmemleak_scan();
+ mutex_unlock(&scan_mutex);
+
+ /* wait before the next scan */
+ while (timeout && !kthread_should_stop())
+ timeout = schedule_timeout_interruptible(timeout);
+ }
+
+ pr_info("Automatic memory scanning thread ended\n");
+
+ return 0;
+}
+
+/*
+ * Start the automatic memory scanning thread. This function must be called
+ * with the scan_mutex held.
+ */
+static void start_scan_thread(void)
+{
+ if (scan_thread)
+ return;
+ scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak");
+ if (IS_ERR(scan_thread)) {
+ pr_warn("Failed to create the scan thread\n");
+ scan_thread = NULL;
+ }
+}
+
+/*
+ * Stop the automatic memory scanning thread.
+ */
+static void stop_scan_thread(void)
+{
+ if (scan_thread) {
+ kthread_stop(scan_thread);
+ scan_thread = NULL;
+ }
+}
+
+/*
+ * Iterate over the object_list and return the first valid object at or after
+ * the required position with its use_count incremented. The function triggers
+ * a memory scanning when the pos argument points to the first position.
+ */
+static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ struct kmemleak_object *object;
+ loff_t n = *pos;
+ int err;
+
+ err = mutex_lock_interruptible(&scan_mutex);
+ if (err < 0)
+ return ERR_PTR(err);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list) {
+ if (n-- > 0)
+ continue;
+ if (get_object(object))
+ goto out;
+ }
+ object = NULL;
+out:
+ return object;
+}
+
+/*
+ * Return the next object in the object_list. The function decrements the
+ * use_count of the previous object and increases that of the next one.
+ */
+static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct kmemleak_object *prev_obj = v;
+ struct kmemleak_object *next_obj = NULL;
+ struct kmemleak_object *obj = prev_obj;
+
+ ++(*pos);
+
+ list_for_each_entry_continue_rcu(obj, &object_list, object_list) {
+ if (get_object(obj)) {
+ next_obj = obj;
+ break;
+ }
+ }
+
+ put_object(prev_obj);
+ return next_obj;
+}
+
+/*
+ * Decrement the use_count of the last object required, if any.
+ */
+static void kmemleak_seq_stop(struct seq_file *seq, void *v)
+{
+ if (!IS_ERR(v)) {
+ /*
+ * kmemleak_seq_start may return ERR_PTR if the scan_mutex
+ * waiting was interrupted, so only release it if !IS_ERR.
+ */
+ rcu_read_unlock();
+ mutex_unlock(&scan_mutex);
+ if (v)
+ put_object(v);
+ }
+}
+
+/*
+ * Print the information for an unreferenced object to the seq file.
+ */
+static int kmemleak_seq_show(struct seq_file *seq, void *v)
+{
+ struct kmemleak_object *object = v;
+ unsigned long flags;
+
+ spin_lock_irqsave(&object->lock, flags);
+ if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object))
+ print_unreferenced(seq, object);
+ spin_unlock_irqrestore(&object->lock, flags);
+ return 0;
+}
+
+static const struct seq_operations kmemleak_seq_ops = {
+ .start = kmemleak_seq_start,
+ .next = kmemleak_seq_next,
+ .stop = kmemleak_seq_stop,
+ .show = kmemleak_seq_show,
+};
+
+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)
+{
+ unsigned long flags;
+ struct kmemleak_object *object;
+ unsigned long addr;
+
+ if (kstrtoul(str, 0, &addr))
+ return -EINVAL;
+ object = find_and_get_object(addr, 0);
+ if (!object) {
+ pr_info("Unknown object at 0x%08lx\n", addr);
+ return -EINVAL;
+ }
+
+ spin_lock_irqsave(&object->lock, flags);
+ dump_object_info(object);
+ spin_unlock_irqrestore(&object->lock, flags);
+
+ put_object(object);
+ return 0;
+}
+
+/*
+ * We use grey instead of black to ensure we can do future scans on the same
+ * objects. If we did not do future scans these black objects could
+ * potentially contain references to newly allocated objects in the future and
+ * we'd end up with false positives.
+ */
+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) {
+ spin_lock_irqsave(&object->lock, flags);
+ if ((object->flags & OBJECT_REPORTED) &&
+ unreferenced_object(object))
+ __paint_it(object, KMEMLEAK_GREY);
+ spin_unlock_irqrestore(&object->lock, flags);
+ }
+ rcu_read_unlock();
+
+ kmemleak_found_leaks = false;
+}
+
+static void __kmemleak_do_cleanup(void);
+
+/*
+ * File write operation to configure kmemleak at run-time. The following
+ * commands can be written to the /sys/kernel/debug/kmemleak file:
+ * off - disable kmemleak (irreversible)
+ * stack=on - enable the task stacks scanning
+ * stack=off - disable the tasks stacks scanning
+ * scan=on - start the automatic memory scanning thread
+ * scan=off - stop the automatic memory scanning thread
+ * scan=... - set the automatic memory scanning period in seconds (0 to
+ * disable it)
+ * scan - trigger a memory scan
+ * clear - mark all current reported unreferenced kmemleak objects as
+ * grey to ignore printing them, or free all kmemleak objects
+ * if kmemleak has been disabled.
+ * dump=... - dump information about the object found at the given address
+ */
+static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
+ size_t size, loff_t *ppos)
+{
+ char buf[64];
+ int buf_size;
+ int ret;
+
+ buf_size = min(size, (sizeof(buf) - 1));
+ if (strncpy_from_user(buf, user_buf, buf_size) < 0)
+ return -EFAULT;
+ buf[buf_size] = 0;
+
+ ret = mutex_lock_interruptible(&scan_mutex);
+ if (ret < 0)
+ return ret;
+
+ if (strncmp(buf, "clear", 5) == 0) {
+ if (kmemleak_enabled)
+ kmemleak_clear();
+ else
+ __kmemleak_do_cleanup();
+ goto out;
+ }
+
+ if (!kmemleak_enabled) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ if (strncmp(buf, "off", 3) == 0)
+ kmemleak_disable();
+ else if (strncmp(buf, "stack=on", 8) == 0)
+ kmemleak_stack_scan = 1;
+ else if (strncmp(buf, "stack=off", 9) == 0)
+ kmemleak_stack_scan = 0;
+ else if (strncmp(buf, "scan=on", 7) == 0)
+ start_scan_thread();
+ else if (strncmp(buf, "scan=off", 8) == 0)
+ stop_scan_thread();
+ else if (strncmp(buf, "scan=", 5) == 0) {
+ unsigned long secs;
+
+ ret = kstrtoul(buf + 5, 0, &secs);
+ if (ret < 0)
+ goto out;
+ stop_scan_thread();
+ if (secs) {
+ jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
+ start_scan_thread();
+ }
+ } else if (strncmp(buf, "scan", 4) == 0)
+ kmemleak_scan();
+ else if (strncmp(buf, "dump=", 5) == 0)
+ ret = dump_str_object_info(buf + 5);
+ else
+ ret = -EINVAL;
+
+out:
+ mutex_unlock(&scan_mutex);
+ if (ret < 0)
+ return ret;
+
+ /* ignore the rest of the buffer, only one command at a time */
+ *ppos += size;
+ return size;
+}
+
+static const struct file_operations kmemleak_fops = {
+ .owner = THIS_MODULE,
+ .open = kmemleak_open,
+ .read = seq_read,
+ .write = kmemleak_write,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static void __kmemleak_do_cleanup(void)
+{
+ struct kmemleak_object *object;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list)
+ delete_object_full(object->pointer);
+ rcu_read_unlock();
+}
+
+/*
+ * Stop the memory scanning thread and free the kmemleak internal objects if
+ * no previous scan thread (otherwise, kmemleak may still have some useful
+ * information on memory leaks).
+ */
+static void kmemleak_do_cleanup(struct work_struct *work)
+{
+ stop_scan_thread();
+
+ mutex_lock(&scan_mutex);
+ /*
+ * Once it is made sure that kmemleak_scan has stopped, it is safe to no
+ * longer track object freeing. Ordering of the scan thread stopping and
+ * the memory accesses below is guaranteed by the kthread_stop()
+ * function.
+ */
+ kmemleak_free_enabled = 0;
+ mutex_unlock(&scan_mutex);
+
+ if (!kmemleak_found_leaks)
+ __kmemleak_do_cleanup();
+ else
+ pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\".\n");
+}
+
+static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
+
+/*
+ * Disable kmemleak. No memory allocation/freeing will be traced once this
+ * function is called. Disabling kmemleak is an irreversible operation.
+ */
+static void kmemleak_disable(void)
+{
+ /* atomically check whether it was already invoked */
+ if (cmpxchg(&kmemleak_error, 0, 1))
+ return;
+
+ /* stop any memory operation tracing */
+ kmemleak_enabled = 0;
+
+ /* check whether it is too early for a kernel thread */
+ if (kmemleak_initialized)
+ schedule_work(&cleanup_work);
+ else
+ kmemleak_free_enabled = 0;
+
+ pr_info("Kernel memory leak detector disabled\n");
+}
+
+/*
+ * Allow boot-time kmemleak disabling (enabled by default).
+ */
+static int __init kmemleak_boot_config(char *str)
+{
+ if (!str)
+ return -EINVAL;
+ if (strcmp(str, "off") == 0)
+ kmemleak_disable();
+ else if (strcmp(str, "on") == 0)
+ kmemleak_skip_disable = 1;
+ else
+ return -EINVAL;
+ return 0;
+}
+early_param("kmemleak", kmemleak_boot_config);
+
+static void __init print_log_trace(struct early_log *log)
+{
+ struct stack_trace trace;
+
+ trace.nr_entries = log->trace_len;
+ trace.entries = log->trace;
+
+ pr_notice("Early log backtrace:\n");
+ print_stack_trace(&trace, 2);
+}
+
+/*
+ * Kmemleak initialization.
+ */
+void __init kmemleak_init(void)
+{
+ int i;
+ unsigned long flags;
+
+#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
+ if (!kmemleak_skip_disable) {
+ kmemleak_early_log = 0;
+ kmemleak_disable();
+ return;
+ }
+#endif
+
+ jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
+ jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
+
+ object_cache = KMEM_CACHE(kmemleak_object, SLAB_NOLEAKTRACE);
+ scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
+
+ if (crt_early_log > ARRAY_SIZE(early_log))
+ pr_warn("Early log buffer exceeded (%d), please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n",
+ crt_early_log);
+
+ /* the kernel is still in UP mode, so disabling the IRQs is enough */
+ local_irq_save(flags);
+ kmemleak_early_log = 0;
+ if (kmemleak_error) {
+ local_irq_restore(flags);
+ return;
+ } else {
+ kmemleak_enabled = 1;
+ kmemleak_free_enabled = 1;
+ }
+ local_irq_restore(flags);
+
+ /*
+ * This is the point where tracking allocations is safe. Automatic
+ * scanning is started during the late initcall. Add the early logged
+ * callbacks to the kmemleak infrastructure.
+ */
+ for (i = 0; i < crt_early_log; i++) {
+ struct early_log *log = &early_log[i];
+
+ switch (log->op_type) {
+ case KMEMLEAK_ALLOC:
+ early_alloc(log);
+ break;
+ case KMEMLEAK_ALLOC_PERCPU:
+ early_alloc_percpu(log);
+ break;
+ case KMEMLEAK_FREE:
+ kmemleak_free(log->ptr);
+ break;
+ case KMEMLEAK_FREE_PART:
+ kmemleak_free_part(log->ptr, log->size);
+ break;
+ case KMEMLEAK_FREE_PERCPU:
+ kmemleak_free_percpu(log->ptr);
+ break;
+ case KMEMLEAK_NOT_LEAK:
+ kmemleak_not_leak(log->ptr);
+ break;
+ case KMEMLEAK_IGNORE:
+ kmemleak_ignore(log->ptr);
+ break;
+ case KMEMLEAK_SCAN_AREA:
+ kmemleak_scan_area(log->ptr, log->size, GFP_KERNEL);
+ break;
+ case KMEMLEAK_NO_SCAN:
+ kmemleak_no_scan(log->ptr);
+ break;
+ case KMEMLEAK_SET_EXCESS_REF:
+ object_set_excess_ref((unsigned long)log->ptr,
+ log->excess_ref);
+ break;
+ default:
+ kmemleak_warn("Unknown early log operation: %d\n",
+ log->op_type);
+ }
+
+ if (kmemleak_warning) {
+ print_log_trace(log);
+ kmemleak_warning = 0;
+ }
+ }
+}
+
+/*
+ * Late initialization function.
+ */
+static int __init kmemleak_late_init(void)
+{
+ struct dentry *dentry;
+
+ kmemleak_initialized = 1;
+
+ dentry = debugfs_create_file("kmemleak", 0644, NULL, NULL,
+ &kmemleak_fops);
+ if (!dentry)
+ pr_warn("Failed to create the debugfs kmemleak file\n");
+
+ if (kmemleak_error) {
+ /*
+ * 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
+ * two clean-up threads but serialized by scan_mutex.
+ */
+ schedule_work(&cleanup_work);
+ return -ENOMEM;
+ }
+
+ mutex_lock(&scan_mutex);
+ start_scan_thread();
+ mutex_unlock(&scan_mutex);
+
+ pr_info("Kernel memory leak detector initialized\n");
+
+ return 0;
+}
+late_initcall(kmemleak_late_init);