cregit-Linux how code gets into the kernel

Release 4.17 mm/kmemleak.c

Directory: mm
/*
 * 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(); }

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/* * 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; }

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static bool color_gray(const struct kmemleak_object *object) { return object->min_count != KMEMLEAK_BLACK && object->count >= object->min_count; }

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/* * 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); }

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/* * 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); } }

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/* * 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); }

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/* * 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; }

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/* * 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); }

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/* * 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); }

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/* * 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); }

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/* * 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; }

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/* * 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; }

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/* * 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; }

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/* * 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; }

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/* * 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); }

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/* * 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); }

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/* * 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); }

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static void __paint_it(struct kmemleak_object *object, int color) { object->min_count = color; if (color == KMEMLEAK_BLACK) object->flags |= OBJECT_NO_SCAN; }

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Luis R. Rodriguez1753.12%150.00%
Catalin Marinas1546.88%150.00%
Total32100.00%2100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas2351.11%150.00%
Luis R. Rodriguez2248.89%150.00%
Total45100.00%2100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas4359.72%250.00%
Luis R. Rodriguez2838.89%125.00%
Joe Perches11.39%125.00%
Total72100.00%4100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Luis R. Rodriguez1376.47%150.00%
Catalin Marinas423.53%150.00%
Total17100.00%2100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Luis R. Rodriguez1376.47%150.00%
Catalin Marinas423.53%150.00%
Total17100.00%2100.00%

/* * 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); }

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PersonTokensPropCommitsCommitProp
Catalin Marinas19898.02%466.67%
Joe Perches41.98%233.33%
Total202100.00%6100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas78100.00%1100.00%
Total78100.00%1100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas7398.65%150.00%
Joe Perches11.35%150.00%
Total74100.00%2100.00%

/* * 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); }

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PersonTokensPropCommitsCommitProp
Catalin Marinas11397.41%583.33%
Wang Kai32.59%116.67%
Total116100.00%6100.00%

/* * 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(); }

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PersonTokensPropCommitsCommitProp
Catalin Marinas13799.28%266.67%
Tetsuo Handa10.72%133.33%
Total138100.00%3100.00%

/* * 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); } }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas47100.00%1100.00%
Total47100.00%1100.00%

/** * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas76100.00%2100.00%
Total76100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas8295.35%150.00%
Larry Finger44.65%150.00%
Total86100.00%2100.00%

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); } }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas108100.00%1100.00%
Total108100.00%1100.00%

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); }

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PersonTokensPropCommitsCommitProp
Catalin Marinas57100.00%4100.00%
Total57100.00%4100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas62100.00%2100.00%
Total62100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas71100.00%2100.00%
Total71100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas109100.00%1100.00%
Total109100.00%1100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas57100.00%2100.00%
Total57100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas57100.00%2100.00%
Total57100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas6797.10%375.00%
Tiejun Chen22.90%125.00%
Total69100.00%4100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas57100.00%2100.00%
Total57100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas47100.00%1100.00%
Total47100.00%1100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas37100.00%1100.00%
Total37100.00%1100.00%

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)); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas32100.00%1100.00%
Total32100.00%1100.00%

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)); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas32100.00%1100.00%
Total32100.00%1100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas4688.46%150.00%
Andrey Ryabinin611.54%150.00%
Total52100.00%2100.00%

/* * 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); } }

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PersonTokensPropCommitsCommitProp
Catalin Marinas59100.00%1100.00%
Total59100.00%1100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas37100.00%1100.00%
Total37100.00%1100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas23393.57%571.43%
Pekka J Enberg104.02%114.29%
Andrey Ryabinin62.41%114.29%
Total249100.00%7100.00%

/* * 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(); } }

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PersonTokensPropCommitsCommitProp
Catalin Marinas53100.00%3100.00%
Total53100.00%3100.00%

/* * 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); }

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PersonTokensPropCommitsCommitProp
Catalin Marinas21699.54%583.33%
Uwe Kleine-König10.46%116.67%
Total217100.00%6100.00%

/* * 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)); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas108100.00%1100.00%
Total108100.00%1100.00%

/* * 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); } }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas50092.42%1050.00%
Yisheng Xie101.85%15.00%
Cody P Schafer71.29%15.00%
Li Zefan61.11%15.00%
Jakub Kiciński50.92%15.00%
Laura Abbott50.92%15.00%
Andrew Morton20.37%15.00%
Kees Cook20.37%15.00%
Vladimir Davydov20.37%15.00%
Joe Perches20.37%210.00%
Total541100.00%20100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas9479.66%360.00%
Vegard Nossum2319.49%120.00%
Joe Perches10.85%120.00%
Total118100.00%5100.00%

/* * 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; } }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas3992.86%125.00%
Joe Perches24.76%250.00%
Luis R. Rodriguez12.38%125.00%
Total42100.00%4100.00%

/* * Stop the automatic memory scanning thread. */
static void stop_scan_thread(void) { if (scan_thread) { kthread_stop(scan_thread); scan_thread = NULL; } }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas2295.65%150.00%
Luis R. Rodriguez14.35%150.00%
Total23100.00%2100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas90100.00%2100.00%
Total90100.00%2100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas7392.41%266.67%
Michael Wang67.59%133.33%
Total79100.00%3100.00%

/* * 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); } }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas44100.00%3100.00%
Total44100.00%3100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas71100.00%2100.00%
Total71100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas25100.00%2100.00%
Total25100.00%2100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas8989.00%150.00%
Abhijit Pawar1111.00%150.00%
Total100100.00%2100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Luis R. Rodriguez7594.94%266.67%
Li Zefan45.06%133.33%
Total79100.00%3100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas31487.47%466.67%
Li Zefan4412.26%116.67%
Jingoo Han10.28%116.67%
Total359100.00%6100.00%

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(); }

Contributors

PersonTokensPropCommitsCommitProp
Li Zefan34100.00%1100.00%
Total34100.00%1100.00%

/* * 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"); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas2657.78%450.00%
Vinayak Menon1328.89%112.50%
Li Zefan511.11%225.00%
Joe Perches12.22%112.50%
Total45100.00%8100.00%

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"); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas4695.83%375.00%
Li Zefan24.17%125.00%
Total48100.00%4100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas5187.93%133.33%
Jason Baron610.34%133.33%
Dou Liyang11.72%133.33%
Total58100.00%3100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas45100.00%1100.00%
Total45100.00%1100.00%

/* * 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; } } }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas28693.16%1071.43%
Jason Baron165.21%17.14%
Li Zefan20.65%17.14%
Joe Perches20.65%17.14%
Wang Kai10.33%17.14%
Total307100.00%14100.00%

/* * Late initialization function. */
static int __init kmemleak_late_init(void) { struct dentry *dentry; kmemleak_initialized = 1; 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; } dentry = debugfs_create_file("kmemleak", 0644, NULL, NULL, &kmemleak_fops); if (!dentry) pr_warn("Failed to create the debugfs kmemleak file\n"); mutex_lock(&scan_mutex); start_scan_thread(); mutex_unlock(&scan_mutex); pr_info("Kernel memory leak detector initialized\n"); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas7994.05%337.50%
Joe Perches22.38%225.00%
Konstantin Khlebnikov11.19%112.50%
Li Zefan11.19%112.50%
Lucas De Marchi11.19%112.50%
Total84100.00%8100.00%

late_initcall(kmemleak_late_init);

Overall Contributors

PersonTokensPropCommitsCommitProp
Catalin Marinas631288.83%4748.96%
Luis R. Rodriguez1852.60%44.17%
Michel Lespinasse1692.38%11.04%
Li Zefan1171.65%44.17%
Sergey Senozhatsky941.32%11.04%
Joe Perches300.42%33.12%
Jason Baron270.38%11.04%
Vegard Nossum230.32%11.04%
Andrey Ryabinin150.21%11.04%
Vinayak Menon140.20%11.04%
Andy Shevchenko110.15%11.04%
Abhijit Pawar110.15%11.04%
Pekka J Enberg100.14%11.04%
Yisheng Xie100.14%11.04%
Laura Abbott80.11%11.04%
Ingo Molnar70.10%33.12%
Dmitriy Vyukov70.10%22.08%
Cody P Schafer70.10%11.04%
Michael Wang60.08%11.04%
Jakub Kiciński50.07%11.04%
Larry Finger50.07%11.04%
Sasha Levin40.06%11.04%
Wang Kai40.06%11.04%
Mike Rapoport40.06%11.04%
Lucas De Marchi30.04%11.04%
Tiejun Chen20.03%11.04%
Vladimir Davydov20.03%11.04%
Andrew Morton20.03%11.04%
Kees Cook20.03%11.04%
Paul Gortmaker10.01%11.04%
Jianpeng Ma (马建朋)10.01%11.04%
Jingoo Han10.01%11.04%
Arun Sharma10.01%11.04%
Dou Liyang10.01%11.04%
Holger Hans Peter Freyther10.01%11.04%
Tetsuo Handa10.01%11.04%
Andreas Platschek10.01%11.04%
Uwe Kleine-König10.01%11.04%
Konstantin Khlebnikov10.01%11.04%
Total7106100.00%96100.00%
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