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mm/kmemleak.c
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// SPDX-License-Identifier: GPL-2.0-only |
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/* * mm/kmemleak.c * * Copyright (C) 2008 ARM Limited * Written by Catalin Marinas <catalin.marinas@arm.com> * |
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* For more information on the algorithm and kmemleak usage, please see |
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* Documentation/dev-tools/kmemleak.rst. |
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* * 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 |
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* blocks. The object_tree_root is a red black tree used to look-up |
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* 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 |
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* 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 |
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* |
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* Locks and mutexes are acquired/nested in the following order: |
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* |
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* 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. |
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* |
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* 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. */ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/init.h> #include <linux/kernel.h> #include <linux/list.h> |
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#include <linux/sched/signal.h> |
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#include <linux/sched/task.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/jiffies.h> #include <linux/delay.h> |
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#include <linux/export.h> |
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#include <linux/kthread.h> |
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#include <linux/rbtree.h> |
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#include <linux/fs.h> #include <linux/debugfs.h> #include <linux/seq_file.h> #include <linux/cpumask.h> #include <linux/spinlock.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> #include <linux/rcupdate.h> #include <linux/stacktrace.h> #include <linux/cache.h> #include <linux/percpu.h> |
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#include <linux/memblock.h> |
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#include <linux/pfn.h> |
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#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> |
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#include <linux/workqueue.h> |
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#include <linux/crc32.h> |
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#include <asm/sections.h> #include <asm/processor.h> |
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#include <linux/atomic.h> |
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#include <linux/kasan.h> |
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#include <linux/kmemleak.h> |
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#include <linux/memory_hotplug.h> |
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/* * Kmemleak configuration and common defines. */ #define MAX_TRACE 16 /* stack trace length */ |
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#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */ |
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#define SECS_FIRST_SCAN 60 /* delay before the first scan */ #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ |
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#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */ |
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#define BYTES_PER_POINTER sizeof(void *) |
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/* GFP bitmask for kmemleak internal allocations */ |
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#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \ |
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__GFP_NORETRY | __GFP_NOMEMALLOC | \ |
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__GFP_NOWARN) |
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/* scanning area inside a memory block */ struct kmemleak_scan_area { struct hlist_node node; |
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unsigned long start; size_t size; |
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}; |
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#define KMEMLEAK_GREY 0 #define KMEMLEAK_BLACK -1 |
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/* * 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 |
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* rb_node are already protected by the corresponding locks or mutex (see |
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* the notes on locking above). These objects are reference-counted * (use_count) and freed using the RCU mechanism. */ struct kmemleak_object { spinlock_t lock; |
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unsigned int flags; /* object status flags */ |
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struct list_head object_list; struct list_head gray_list; |
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struct rb_node rb_node; |
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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; |
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/* pass surplus references to this pointer */ unsigned long excess_ref; |
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/* 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; |
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/* checksum for detecting modified objects */ u32 checksum; |
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/* 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) |
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/* flag set to fully scan the object when scan_area allocation failed */ #define OBJECT_FULL_SCAN (1 << 3) |
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#define HEX_PREFIX " " |
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/* 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 |
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/* 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); |
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/* memory pool allocation */ |
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static struct kmemleak_object mem_pool[CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE]; |
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static int mem_pool_free_count = ARRAY_SIZE(mem_pool); static LIST_HEAD(mem_pool_free_list); |
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/* 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 */ |
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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 */ |
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static int kmemleak_enabled = 1; |
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/* same as above but only for the kmemleak_free() callback */ |
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static int kmemleak_free_enabled = 1; |
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/* set in the late_initcall if there were no errors */ |
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static int kmemleak_initialized; |
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/* set if a kmemleak warning was issued */ |
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static int kmemleak_warning; |
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/* set if a fatal kmemleak error has occurred */ |
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static int kmemleak_error; |
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/* minimum and maximum address that may be valid pointers */ static unsigned long min_addr = ULONG_MAX; static unsigned long max_addr; |
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static struct task_struct *scan_thread; |
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/* used to avoid reporting of recently allocated objects */ |
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static unsigned long jiffies_min_age; |
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static unsigned long jiffies_last_scan; |
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/* delay between automatic memory scannings */ static signed long jiffies_scan_wait; /* enables or disables the task stacks scanning */ |
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static int kmemleak_stack_scan = 1; |
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/* protects the memory scanning, parameters and debug/kmemleak file access */ |
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static DEFINE_MUTEX(scan_mutex); |
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/* setting kmemleak=on, will set this var, skipping the disable */ static int kmemleak_skip_disable; |
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/* If there are leaks that can be reported */ static bool kmemleak_found_leaks; |
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static bool kmemleak_verbose; module_param_named(verbose, kmemleak_verbose, bool, 0600); |
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static void kmemleak_disable(void); /* * Print a warning and dump the stack trace. */ |
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#define kmemleak_warn(x...) do { \ |
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pr_warn(x); \ |
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dump_stack(); \ |
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kmemleak_warning = 1; \ |
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} while (0) /* |
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* Macro invoked when a serious kmemleak condition occurred and cannot be |
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* recovered from. Kmemleak will be disabled and further allocation/freeing |
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* tracing no longer available. */ |
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#define kmemleak_stop(x...) do { \ |
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kmemleak_warn(x); \ kmemleak_disable(); \ } while (0) |
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#define warn_or_seq_printf(seq, fmt, ...) do { \ if (seq) \ seq_printf(seq, fmt, ##__VA_ARGS__); \ else \ pr_warn(fmt, ##__VA_ARGS__); \ } while (0) static void warn_or_seq_hex_dump(struct seq_file *seq, int prefix_type, int rowsize, int groupsize, const void *buf, size_t len, bool ascii) { if (seq) seq_hex_dump(seq, HEX_PREFIX, prefix_type, rowsize, groupsize, buf, len, ascii); else print_hex_dump(KERN_WARNING, pr_fmt(HEX_PREFIX), prefix_type, rowsize, groupsize, buf, len, ascii); } |
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/* |
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* 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; |
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size_t len; |
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/* limit the number of lines to HEX_MAX_LINES */ |
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len = min_t(size_t, object->size, HEX_MAX_LINES * HEX_ROW_SIZE); |
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warn_or_seq_printf(seq, " hex dump (first %zu bytes): ", len); |
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kasan_disable_current(); |
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warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE, HEX_GROUP_SIZE, ptr, len, HEX_ASCII); |
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kasan_enable_current(); |
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} /* |
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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. */ |
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static bool color_white(const struct kmemleak_object *object) |
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{ |
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return object->count != KMEMLEAK_BLACK && object->count < object->min_count; |
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} |
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static bool color_gray(const struct kmemleak_object *object) |
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{ |
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return object->min_count != KMEMLEAK_BLACK && object->count >= object->min_count; |
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} /* |
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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. */ |
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static bool unreferenced_object(struct kmemleak_object *object) |
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{ |
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return (color_white(object) && object->flags & OBJECT_ALLOCATED) && |
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time_before_eq(object->jiffies + jiffies_min_age, jiffies_last_scan); |
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} /* |
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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. |
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*/ |
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static void print_unreferenced(struct seq_file *seq, struct kmemleak_object *object) { int i; |
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unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); |
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warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu): ", |
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object->pointer, object->size); |
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warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds) ", |
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object->comm, object->pid, object->jiffies, msecs_age / 1000, msecs_age % 1000); |
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hex_dump_object(seq, object); |
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warn_or_seq_printf(seq, " backtrace: "); |
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for (i = 0; i < object->trace_len; i++) { void *ptr = (void *)object->trace[i]; |
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warn_or_seq_printf(seq, " [<%p>] %pS ", 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) { |
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pr_notice("Object 0x%08lx (size %zu): ", |
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object->pointer, object->size); |
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pr_notice(" comm \"%s\", pid %d, jiffies %lu ", object->comm, object->pid, object->jiffies); pr_notice(" min_count = %d ", object->min_count); pr_notice(" count = %d ", object->count); |
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pr_notice(" flags = 0x%x ", object->flags); |
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pr_notice(" checksum = %u ", object->checksum); |
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pr_notice(" backtrace: "); |
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stack_trace_print(object->trace, object->trace_len, 4); |
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} /* |
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* Look-up a memory block metadata (kmemleak_object) in the object search |
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* 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) { |
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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 { |
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kmemleak_warn("Found object by alias at 0x%08lx ", ptr); |
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dump_object_info(object); |
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break; |
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} |
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} 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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* Memory pool allocation and freeing. kmemleak_lock must not be held. */ static struct kmemleak_object *mem_pool_alloc(gfp_t gfp) { unsigned long flags; struct kmemleak_object *object; /* try the slab allocator first */ |
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if (object_cache) { object = kmem_cache_alloc(object_cache, gfp_kmemleak_mask(gfp)); if (object) return object; } |
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/* slab allocation failed, try the memory pool */ write_lock_irqsave(&kmemleak_lock, flags); object = list_first_entry_or_null(&mem_pool_free_list, typeof(*object), object_list); if (object) list_del(&object->object_list); else if (mem_pool_free_count) object = &mem_pool[--mem_pool_free_count]; |
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else pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE "); |
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write_unlock_irqrestore(&kmemleak_lock, flags); return object; } /* * Return the object to either the slab allocator or the memory pool. */ static void mem_pool_free(struct kmemleak_object *object) { unsigned long flags; if (object < mem_pool || object >= mem_pool + ARRAY_SIZE(mem_pool)) { kmem_cache_free(object_cache, object); return; } /* add the object to the memory pool free list */ write_lock_irqsave(&kmemleak_lock, flags); list_add(&object->object_list, &mem_pool_free_list); write_unlock_irqrestore(&kmemleak_lock, flags); } /* |
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* RCU callback to free a kmemleak_object. */ static void free_object_rcu(struct rcu_head *rcu) { |
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struct hlist_node *tmp; |
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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. */ |
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hlist_for_each_entry_safe(area, tmp, &object->area_list, node) { hlist_del(&area->node); |
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|
480 481 |
kmem_cache_free(scan_area_cache, area); } |
0647398a8
|
482 |
mem_pool_free(object); |
3c7b4e6b8
|
483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 |
} /* * 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); |
c56658681
|
499 500 501 502 503 504 505 506 507 |
/* * It may be too early for the RCU callbacks, however, there is no * concurrent object_list traversal when !object_cache and all objects * came from the memory pool. Free the object directly. */ if (object_cache) call_rcu(&object->rcu, free_object_rcu); else free_object_rcu(&object->rcu); |
3c7b4e6b8
|
508 509 510 |
} /* |
85d3a316c
|
511 |
* Look up an object in the object search tree and increase its use_count. |
3c7b4e6b8
|
512 513 514 515 |
*/ static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias) { unsigned long flags; |
9fbed2540
|
516 |
struct kmemleak_object *object; |
3c7b4e6b8
|
517 518 519 |
rcu_read_lock(); read_lock_irqsave(&kmemleak_lock, flags); |
93ada579b
|
520 |
object = lookup_object(ptr, alias); |
3c7b4e6b8
|
521 522 523 524 525 526 527 528 529 530 531 |
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; } /* |
2abd839aa
|
532 533 534 535 536 537 538 539 540 541 |
* Remove an object from the object_tree_root and object_list. Must be called * with the kmemleak_lock held _if_ kmemleak is still enabled. */ static void __remove_object(struct kmemleak_object *object) { rb_erase(&object->rb_node, &object_tree_root); list_del_rcu(&object->object_list); } /* |
e781a9ab4
|
542 543 544 545 546 547 548 549 550 551 552 |
* 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); |
2abd839aa
|
553 554 |
if (object) __remove_object(object); |
e781a9ab4
|
555 556 557 558 559 560 |
write_unlock_irqrestore(&kmemleak_lock, flags); return object; } /* |
fd6789675
|
561 562 563 564 |
* Save stack trace to the given array of MAX_TRACE size. */ static int __save_stack_trace(unsigned long *trace) { |
07984aad1
|
565 |
return stack_trace_save(trace, MAX_TRACE, 2); |
fd6789675
|
566 567 568 |
} /* |
3c7b4e6b8
|
569 570 571 |
* Create the metadata (struct kmemleak_object) corresponding to an allocated * memory block and add it to the object_list and object_tree_root. */ |
fd6789675
|
572 573 |
static struct kmemleak_object *create_object(unsigned long ptr, size_t size, int min_count, gfp_t gfp) |
3c7b4e6b8
|
574 575 |
{ unsigned long flags; |
85d3a316c
|
576 577 |
struct kmemleak_object *object, *parent; struct rb_node **link, *rb_parent; |
a2f775751
|
578 |
unsigned long untagged_ptr; |
3c7b4e6b8
|
579 |
|
0647398a8
|
580 |
object = mem_pool_alloc(gfp); |
3c7b4e6b8
|
581 |
if (!object) { |
598d80914
|
582 583 |
pr_warn("Cannot allocate a kmemleak_object structure "); |
6ae4bd1f0
|
584 |
kmemleak_disable(); |
fd6789675
|
585 |
return NULL; |
3c7b4e6b8
|
586 587 588 589 590 591 592 |
} 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); |
04609ccc4
|
593 |
object->flags = OBJECT_ALLOCATED; |
3c7b4e6b8
|
594 595 |
object->pointer = ptr; object->size = size; |
94f4a1618
|
596 |
object->excess_ref = 0; |
3c7b4e6b8
|
597 |
object->min_count = min_count; |
04609ccc4
|
598 |
object->count = 0; /* white color initially */ |
3c7b4e6b8
|
599 |
object->jiffies = jiffies; |
04609ccc4
|
600 |
object->checksum = 0; |
3c7b4e6b8
|
601 602 603 604 605 |
/* task information */ if (in_irq()) { object->pid = 0; strncpy(object->comm, "hardirq", sizeof(object->comm)); |
6ef905695
|
606 |
} else if (in_serving_softirq()) { |
3c7b4e6b8
|
607 608 609 610 611 612 613 614 615 616 617 618 619 620 |
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 */ |
fd6789675
|
621 |
object->trace_len = __save_stack_trace(object->trace); |
3c7b4e6b8
|
622 |
|
3c7b4e6b8
|
623 |
write_lock_irqsave(&kmemleak_lock, flags); |
0580a1819
|
624 |
|
a2f775751
|
625 626 627 |
untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr); min_addr = min(min_addr, untagged_ptr); max_addr = max(max_addr, untagged_ptr + size); |
85d3a316c
|
628 629 630 631 632 633 634 635 636 637 |
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 { |
756a025f0
|
638 639 |
kmemleak_stop("Cannot insert 0x%lx into the object search tree (overlaps existing) ", |
85d3a316c
|
640 |
ptr); |
9d5a4c730
|
641 642 643 644 645 |
/* * No need for parent->lock here since "parent" cannot * be freed while the kmemleak_lock is held. */ dump_object_info(parent); |
85d3a316c
|
646 |
kmem_cache_free(object_cache, object); |
9d5a4c730
|
647 |
object = NULL; |
85d3a316c
|
648 649 |
goto out; } |
3c7b4e6b8
|
650 |
} |
85d3a316c
|
651 652 |
rb_link_node(&object->rb_node, rb_parent, link); rb_insert_color(&object->rb_node, &object_tree_root); |
3c7b4e6b8
|
653 654 655 |
list_add_tail_rcu(&object->object_list, &object_list); out: write_unlock_irqrestore(&kmemleak_lock, flags); |
fd6789675
|
656 |
return object; |
3c7b4e6b8
|
657 658 659 |
} /* |
e781a9ab4
|
660 |
* Mark the object as not allocated and schedule RCU freeing via put_object(). |
3c7b4e6b8
|
661 |
*/ |
53238a60d
|
662 |
static void __delete_object(struct kmemleak_object *object) |
3c7b4e6b8
|
663 664 |
{ unsigned long flags; |
3c7b4e6b8
|
665 |
|
3c7b4e6b8
|
666 |
WARN_ON(!(object->flags & OBJECT_ALLOCATED)); |
e781a9ab4
|
667 |
WARN_ON(atomic_read(&object->use_count) < 1); |
3c7b4e6b8
|
668 669 670 671 672 673 |
/* * Locking here also ensures that the corresponding memory block * cannot be freed when it is being scanned. */ spin_lock_irqsave(&object->lock, flags); |
3c7b4e6b8
|
674 675 676 677 678 679 |
object->flags &= ~OBJECT_ALLOCATED; spin_unlock_irqrestore(&object->lock, flags); put_object(object); } /* |
53238a60d
|
680 681 682 683 684 685 |
* 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; |
e781a9ab4
|
686 |
object = find_and_remove_object(ptr, 0); |
53238a60d
|
687 688 689 690 691 692 693 694 695 |
if (!object) { #ifdef DEBUG kmemleak_warn("Freeing unknown object at 0x%08lx ", ptr); #endif return; } __delete_object(object); |
53238a60d
|
696 697 698 699 700 701 702 703 704 705 706 |
} /* * 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; |
e781a9ab4
|
707 |
object = find_and_remove_object(ptr, 1); |
53238a60d
|
708 709 |
if (!object) { #ifdef DEBUG |
756a025f0
|
710 711 712 |
kmemleak_warn("Partially freeing unknown object at 0x%08lx (size %zu) ", ptr, size); |
53238a60d
|
713 714 715 |
#endif return; } |
53238a60d
|
716 717 718 719 |
/* * Create one or two objects that may result from the memory block * split. Note that partial freeing is only done by free_bootmem() and |
c56658681
|
720 |
* this happens before kmemleak_init() is called. |
53238a60d
|
721 722 723 724 725 726 727 728 729 |
*/ 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); |
e781a9ab4
|
730 |
__delete_object(object); |
53238a60d
|
731 |
} |
a1084c877
|
732 733 734 735 736 737 738 739 740 |
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) |
3c7b4e6b8
|
741 742 |
{ unsigned long flags; |
a1084c877
|
743 744 745 746 747 748 749 750 |
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) { |
3c7b4e6b8
|
751 752 753 754 |
struct kmemleak_object *object; object = find_and_get_object(ptr, 0); if (!object) { |
756a025f0
|
755 756 757 |
kmemleak_warn("Trying to color unknown object at 0x%08lx as %s ", ptr, |
a1084c877
|
758 759 |
(color == KMEMLEAK_GREY) ? "Grey" : (color == KMEMLEAK_BLACK) ? "Black" : "Unknown"); |
3c7b4e6b8
|
760 761 |
return; } |
a1084c877
|
762 |
paint_it(object, color); |
3c7b4e6b8
|
763 764 765 766 |
put_object(object); } /* |
145b64b95
|
767 |
* Mark an object permanently as gray-colored so that it can no longer be |
a1084c877
|
768 769 770 771 772 773 774 775 |
* 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); } /* |
3c7b4e6b8
|
776 777 778 779 780 |
* Mark the object as black-colored so that it is ignored from scans and * reporting. */ static void make_black_object(unsigned long ptr) { |
a1084c877
|
781 |
paint_ptr(ptr, KMEMLEAK_BLACK); |
3c7b4e6b8
|
782 783 784 785 786 787 |
} /* * 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. */ |
c017b4be3
|
788 |
static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp) |
3c7b4e6b8
|
789 790 791 |
{ unsigned long flags; struct kmemleak_object *object; |
c56658681
|
792 |
struct kmemleak_scan_area *area = NULL; |
3c7b4e6b8
|
793 |
|
c017b4be3
|
794 |
object = find_and_get_object(ptr, 1); |
3c7b4e6b8
|
795 |
if (!object) { |
ae281064b
|
796 797 798 |
kmemleak_warn("Adding scan area to unknown object at 0x%08lx ", ptr); |
3c7b4e6b8
|
799 800 |
return; } |
c56658681
|
801 802 |
if (scan_area_cache) area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp)); |
3c7b4e6b8
|
803 804 |
spin_lock_irqsave(&object->lock, flags); |
dba82d943
|
805 806 807 808 809 810 811 |
if (!area) { pr_warn_once("Cannot allocate a scan area, scanning the full object "); /* mark the object for full scan to avoid false positives */ object->flags |= OBJECT_FULL_SCAN; goto out_unlock; } |
7f88f88f8
|
812 813 814 |
if (size == SIZE_MAX) { size = object->pointer + object->size - ptr; } else if (ptr + size > object->pointer + object->size) { |
ae281064b
|
815 816 |
kmemleak_warn("Scan area larger than object 0x%08lx ", ptr); |
3c7b4e6b8
|
817 818 819 820 821 822 |
dump_object_info(object); kmem_cache_free(scan_area_cache, area); goto out_unlock; } INIT_HLIST_NODE(&area->node); |
c017b4be3
|
823 824 |
area->start = ptr; area->size = size; |
3c7b4e6b8
|
825 826 827 828 |
hlist_add_head(&area->node, &object->area_list); out_unlock: spin_unlock_irqrestore(&object->lock, flags); |
3c7b4e6b8
|
829 830 831 832 |
put_object(object); } /* |
94f4a1618
|
833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 |
* 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 ", ptr); return; } spin_lock_irqsave(&object->lock, flags); object->excess_ref = excess_ref; spin_unlock_irqrestore(&object->lock, flags); put_object(object); } /* |
3c7b4e6b8
|
858 859 860 861 862 863 864 865 866 867 868 |
* 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) { |
ae281064b
|
869 870 |
kmemleak_warn("Not scanning unknown object at 0x%08lx ", ptr); |
3c7b4e6b8
|
871 872 873 874 875 876 877 878 |
return; } spin_lock_irqsave(&object->lock, flags); object->flags |= OBJECT_NO_SCAN; spin_unlock_irqrestore(&object->lock, flags); put_object(object); } |
a2b6bf63c
|
879 880 881 882 883 884 885 886 887 888 889 890 |
/** * 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 |
94f4a1618
|
891 |
* (memory block) is allocated (kmem_cache_alloc, kmalloc etc.). |
3c7b4e6b8
|
892 |
*/ |
a6186d89c
|
893 894 |
void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count, gfp_t gfp) |
3c7b4e6b8
|
895 896 897 |
{ pr_debug("%s(0x%p, %zu, %d) ", __func__, ptr, size, min_count); |
8910ae896
|
898 |
if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b8
|
899 |
create_object((unsigned long)ptr, size, min_count, gfp); |
3c7b4e6b8
|
900 901 |
} EXPORT_SYMBOL_GPL(kmemleak_alloc); |
a2b6bf63c
|
902 |
/** |
f528f0b8e
|
903 904 905 |
* kmemleak_alloc_percpu - register a newly allocated __percpu object * @ptr: __percpu pointer to beginning of the object * @size: size of the object |
8a8c35fad
|
906 |
* @gfp: flags used for kmemleak internal memory allocations |
f528f0b8e
|
907 908 |
* * This function is called from the kernel percpu allocator when a new object |
8a8c35fad
|
909 |
* (memory block) is allocated (alloc_percpu). |
f528f0b8e
|
910 |
*/ |
8a8c35fad
|
911 912 |
void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size, gfp_t gfp) |
f528f0b8e
|
913 914 915 916 917 918 919 920 921 922 |
{ unsigned int cpu; pr_debug("%s(0x%p, %zu) ", __func__, ptr, size); /* * Percpu allocations are only scanned and not reported as leaks * (min_count is set to 0). */ |
8910ae896
|
923 |
if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8e
|
924 925 |
for_each_possible_cpu(cpu) create_object((unsigned long)per_cpu_ptr(ptr, cpu), |
8a8c35fad
|
926 |
size, 0, gfp); |
f528f0b8e
|
927 928 929 930 |
} EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu); /** |
94f4a1618
|
931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 |
* 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) ", __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); |
94f4a1618
|
952 953 954 955 956 |
} } EXPORT_SYMBOL_GPL(kmemleak_vmalloc); /** |
a2b6bf63c
|
957 958 959 960 961 |
* 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.). |
3c7b4e6b8
|
962 |
*/ |
a6186d89c
|
963 |
void __ref kmemleak_free(const void *ptr) |
3c7b4e6b8
|
964 965 966 |
{ pr_debug("%s(0x%p) ", __func__, ptr); |
c5f3b1a51
|
967 |
if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
53238a60d
|
968 |
delete_object_full((unsigned long)ptr); |
3c7b4e6b8
|
969 970 |
} EXPORT_SYMBOL_GPL(kmemleak_free); |
a2b6bf63c
|
971 972 973 974 975 976 977 978 |
/** * 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). |
53238a60d
|
979 |
*/ |
a6186d89c
|
980 |
void __ref kmemleak_free_part(const void *ptr, size_t size) |
53238a60d
|
981 982 983 |
{ pr_debug("%s(0x%p) ", __func__, ptr); |
8910ae896
|
984 |
if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
53238a60d
|
985 |
delete_object_part((unsigned long)ptr, size); |
53238a60d
|
986 987 |
} EXPORT_SYMBOL_GPL(kmemleak_free_part); |
a2b6bf63c
|
988 |
/** |
f528f0b8e
|
989 990 991 992 993 994 995 996 997 998 999 1000 |
* 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) ", __func__, ptr); |
c5f3b1a51
|
1001 |
if (kmemleak_free_enabled && ptr && !IS_ERR(ptr)) |
f528f0b8e
|
1002 1003 1004 |
for_each_possible_cpu(cpu) delete_object_full((unsigned long)per_cpu_ptr(ptr, cpu)); |
f528f0b8e
|
1005 1006 1007 1008 |
} EXPORT_SYMBOL_GPL(kmemleak_free_percpu); /** |
ffe2c748e
|
1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 |
* 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) ", __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 ", 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); /** |
a2b6bf63c
|
1045 1046 1047 1048 1049 |
* 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. |
3c7b4e6b8
|
1050 |
*/ |
a6186d89c
|
1051 |
void __ref kmemleak_not_leak(const void *ptr) |
3c7b4e6b8
|
1052 1053 1054 |
{ pr_debug("%s(0x%p) ", __func__, ptr); |
8910ae896
|
1055 |
if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b8
|
1056 |
make_gray_object((unsigned long)ptr); |
3c7b4e6b8
|
1057 1058 |
} EXPORT_SYMBOL(kmemleak_not_leak); |
a2b6bf63c
|
1059 1060 1061 1062 1063 1064 1065 1066 |
/** * 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. |
3c7b4e6b8
|
1067 |
*/ |
a6186d89c
|
1068 |
void __ref kmemleak_ignore(const void *ptr) |
3c7b4e6b8
|
1069 1070 1071 |
{ pr_debug("%s(0x%p) ", __func__, ptr); |
8910ae896
|
1072 |
if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b8
|
1073 |
make_black_object((unsigned long)ptr); |
3c7b4e6b8
|
1074 1075 |
} EXPORT_SYMBOL(kmemleak_ignore); |
a2b6bf63c
|
1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 |
/** * 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. |
3c7b4e6b8
|
1086 |
*/ |
c017b4be3
|
1087 |
void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) |
3c7b4e6b8
|
1088 1089 1090 |
{ pr_debug("%s(0x%p) ", __func__, ptr); |
8910ae896
|
1091 |
if (kmemleak_enabled && ptr && size && !IS_ERR(ptr)) |
c017b4be3
|
1092 |
add_scan_area((unsigned long)ptr, size, gfp); |
3c7b4e6b8
|
1093 1094 |
} EXPORT_SYMBOL(kmemleak_scan_area); |
a2b6bf63c
|
1095 1096 1097 1098 1099 1100 1101 1102 |
/** * 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. |
3c7b4e6b8
|
1103 |
*/ |
a6186d89c
|
1104 |
void __ref kmemleak_no_scan(const void *ptr) |
3c7b4e6b8
|
1105 1106 1107 |
{ pr_debug("%s(0x%p) ", __func__, ptr); |
8910ae896
|
1108 |
if (kmemleak_enabled && ptr && !IS_ERR(ptr)) |
3c7b4e6b8
|
1109 |
object_no_scan((unsigned long)ptr); |
3c7b4e6b8
|
1110 1111 |
} EXPORT_SYMBOL(kmemleak_no_scan); |
9099daed9
|
1112 1113 1114 |
/** * kmemleak_alloc_phys - similar to kmemleak_alloc but taking a physical * address argument |
e8b098fc5
|
1115 1116 1117 1118 1119 |
* @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 |
9099daed9
|
1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 |
*/ 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 |
e8b098fc5
|
1132 1133 1134 |
* @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 |
9099daed9
|
1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 |
*/ 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 |
e8b098fc5
|
1146 |
* @phys: physical address of the object |
9099daed9
|
1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 |
*/ 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 |
e8b098fc5
|
1158 |
* @phys: physical address of the object |
9099daed9
|
1159 1160 1161 1162 1163 1164 1165 |
*/ 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); |
3c7b4e6b8
|
1166 |
/* |
04609ccc4
|
1167 1168 1169 1170 1171 |
* 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; |
e79ed2f13
|
1172 |
kasan_disable_current(); |
04609ccc4
|
1173 |
object->checksum = crc32(0, (void *)object->pointer, object->size); |
e79ed2f13
|
1174 |
kasan_enable_current(); |
04609ccc4
|
1175 1176 1177 1178 |
return object->checksum != old_csum; } /* |
04f70d13c
|
1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 |
* 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); } } /* |
3c7b4e6b8
|
1203 |
* Memory scanning is a long process and it needs to be interruptable. This |
25985edce
|
1204 |
* function checks whether such interrupt condition occurred. |
3c7b4e6b8
|
1205 1206 1207 |
*/ static int scan_should_stop(void) { |
8910ae896
|
1208 |
if (!kmemleak_enabled) |
3c7b4e6b8
|
1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 |
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, |
93ada579b
|
1228 |
struct kmemleak_object *scanned) |
3c7b4e6b8
|
1229 1230 1231 1232 |
{ unsigned long *ptr; unsigned long *start = PTR_ALIGN(_start, BYTES_PER_POINTER); unsigned long *end = _end - (BYTES_PER_POINTER - 1); |
93ada579b
|
1233 |
unsigned long flags; |
a2f775751
|
1234 |
unsigned long untagged_ptr; |
3c7b4e6b8
|
1235 |
|
93ada579b
|
1236 |
read_lock_irqsave(&kmemleak_lock, flags); |
3c7b4e6b8
|
1237 |
for (ptr = start; ptr < end; ptr++) { |
3c7b4e6b8
|
1238 |
struct kmemleak_object *object; |
8e019366b
|
1239 |
unsigned long pointer; |
94f4a1618
|
1240 |
unsigned long excess_ref; |
3c7b4e6b8
|
1241 1242 1243 |
if (scan_should_stop()) break; |
e79ed2f13
|
1244 |
kasan_disable_current(); |
8e019366b
|
1245 |
pointer = *ptr; |
e79ed2f13
|
1246 |
kasan_enable_current(); |
8e019366b
|
1247 |
|
a2f775751
|
1248 1249 |
untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer); if (untagged_ptr < min_addr || untagged_ptr >= max_addr) |
93ada579b
|
1250 1251 1252 1253 1254 1255 1256 1257 1258 |
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); |
3c7b4e6b8
|
1259 1260 |
if (!object) continue; |
93ada579b
|
1261 |
if (object == scanned) |
3c7b4e6b8
|
1262 |
/* self referenced, ignore */ |
3c7b4e6b8
|
1263 |
continue; |
3c7b4e6b8
|
1264 1265 1266 1267 1268 1269 |
/* * Avoid the lockdep recursive warning on object->lock being * previously acquired in scan_object(). These locks are * enclosed by scan_mutex. */ |
93ada579b
|
1270 |
spin_lock_nested(&object->lock, SINGLE_DEPTH_NESTING); |
94f4a1618
|
1271 1272 1273 1274 1275 1276 1277 1278 |
/* 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); } |
93ada579b
|
1279 |
spin_unlock(&object->lock); |
94f4a1618
|
1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 |
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); } |
93ada579b
|
1292 1293 1294 |
} read_unlock_irqrestore(&kmemleak_lock, flags); } |
0587da40b
|
1295 |
|
93ada579b
|
1296 1297 1298 |
/* * Scan a large memory block in MAX_SCAN_SIZE chunks to reduce the latency. */ |
dce5b0bde
|
1299 |
#ifdef CONFIG_SMP |
93ada579b
|
1300 1301 1302 1303 1304 1305 1306 1307 1308 |
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(); |
3c7b4e6b8
|
1309 1310 |
} } |
dce5b0bde
|
1311 |
#endif |
3c7b4e6b8
|
1312 1313 1314 1315 1316 1317 1318 1319 |
/* * 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; |
3c7b4e6b8
|
1320 1321 1322 |
unsigned long flags; /* |
21ae2956c
|
1323 1324 |
* Once the object->lock is acquired, the corresponding memory block * cannot be freed (the same lock is acquired in delete_object). |
3c7b4e6b8
|
1325 1326 1327 1328 1329 1330 1331 |
*/ spin_lock_irqsave(&object->lock, flags); if (object->flags & OBJECT_NO_SCAN) goto out; if (!(object->flags & OBJECT_ALLOCATED)) /* already freed object */ goto out; |
dba82d943
|
1332 1333 |
if (hlist_empty(&object->area_list) || object->flags & OBJECT_FULL_SCAN) { |
af98603da
|
1334 1335 |
void *start = (void *)object->pointer; void *end = (void *)(object->pointer + object->size); |
93ada579b
|
1336 1337 1338 1339 1340 |
void *next; do { next = min(start + MAX_SCAN_SIZE, end); scan_block(start, next, object); |
af98603da
|
1341 |
|
93ada579b
|
1342 1343 1344 |
start = next; if (start >= end) break; |
af98603da
|
1345 1346 1347 1348 |
spin_unlock_irqrestore(&object->lock, flags); cond_resched(); spin_lock_irqsave(&object->lock, flags); |
93ada579b
|
1349 |
} while (object->flags & OBJECT_ALLOCATED); |
af98603da
|
1350 |
} else |
b67bfe0d4
|
1351 |
hlist_for_each_entry(area, &object->area_list, node) |
c017b4be3
|
1352 1353 |
scan_block((void *)area->start, (void *)(area->start + area->size), |
93ada579b
|
1354 |
object); |
3c7b4e6b8
|
1355 1356 1357 1358 1359 |
out: spin_unlock_irqrestore(&object->lock, flags); } /* |
04609ccc4
|
1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 |
* 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)); } /* |
3c7b4e6b8
|
1393 1394 1395 1396 1397 1398 1399 |
* 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; |
04609ccc4
|
1400 |
struct kmemleak_object *object; |
3c7b4e6b8
|
1401 |
int i; |
4698c1f2b
|
1402 |
int new_leaks = 0; |
3c7b4e6b8
|
1403 |
|
acf4968ec
|
1404 |
jiffies_last_scan = jiffies; |
3c7b4e6b8
|
1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 |
/* 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) { |
ae281064b
|
1415 1416 |
pr_debug("object->use_count = %d ", |
3c7b4e6b8
|
1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 |
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(); |
3c7b4e6b8
|
1429 1430 1431 |
#ifdef CONFIG_SMP /* per-cpu sections scanning */ for_each_possible_cpu(i) |
93ada579b
|
1432 1433 |
scan_large_block(__per_cpu_start + per_cpu_offset(i), __per_cpu_end + per_cpu_offset(i)); |
3c7b4e6b8
|
1434 1435 1436 |
#endif /* |
029aeff5d
|
1437 |
* Struct page scanning for each node. |
3c7b4e6b8
|
1438 |
*/ |
bfc8c9013
|
1439 |
get_online_mems(); |
3c7b4e6b8
|
1440 |
for_each_online_node(i) { |
108bcc96e
|
1441 1442 |
unsigned long start_pfn = node_start_pfn(i); unsigned long end_pfn = node_end_pfn(i); |
3c7b4e6b8
|
1443 1444 1445 |
unsigned long pfn; for (pfn = start_pfn; pfn < end_pfn; pfn++) { |
9f1eb38e0
|
1446 |
struct page *page = pfn_to_online_page(pfn); |
3c7b4e6b8
|
1447 |
|
9f1eb38e0
|
1448 1449 1450 1451 1452 |
if (!page) continue; /* only scan pages belonging to this node */ if (page_to_nid(page) != i) |
3c7b4e6b8
|
1453 |
continue; |
3c7b4e6b8
|
1454 1455 1456 |
/* only scan if page is in use */ if (page_count(page) == 0) continue; |
93ada579b
|
1457 |
scan_block(page, page + 1, NULL); |
13ab183d1
|
1458 |
if (!(pfn & 63)) |
bde5f6bc6
|
1459 |
cond_resched(); |
3c7b4e6b8
|
1460 1461 |
} } |
bfc8c9013
|
1462 |
put_online_mems(); |
3c7b4e6b8
|
1463 1464 |
/* |
43ed5d6ee
|
1465 |
* Scanning the task stacks (may introduce false negatives). |
3c7b4e6b8
|
1466 1467 |
*/ if (kmemleak_stack_scan) { |
43ed5d6ee
|
1468 |
struct task_struct *p, *g; |
3c7b4e6b8
|
1469 |
read_lock(&tasklist_lock); |
43ed5d6ee
|
1470 |
do_each_thread(g, p) { |
37df49f43
|
1471 1472 1473 1474 1475 |
void *stack = try_get_task_stack(p); if (stack) { scan_block(stack, stack + THREAD_SIZE, NULL); put_task_stack(p); } |
43ed5d6ee
|
1476 |
} while_each_thread(g, p); |
3c7b4e6b8
|
1477 1478 1479 1480 1481 |
read_unlock(&tasklist_lock); } /* * Scan the objects already referenced from the sections scanned |
04609ccc4
|
1482 |
* above. |
3c7b4e6b8
|
1483 |
*/ |
04609ccc4
|
1484 |
scan_gray_list(); |
2587362ea
|
1485 1486 |
/* |
04609ccc4
|
1487 1488 |
* Check for new or unreferenced objects modified since the previous * scan and color them gray until the next scan. |
2587362ea
|
1489 1490 1491 1492 |
*/ rcu_read_lock(); list_for_each_entry_rcu(object, &object_list, object_list) { spin_lock_irqsave(&object->lock, flags); |
04609ccc4
|
1493 1494 1495 1496 |
if (color_white(object) && (object->flags & OBJECT_ALLOCATED) && update_checksum(object) && get_object(object)) { /* color it gray temporarily */ object->count = object->min_count; |
2587362ea
|
1497 1498 1499 1500 1501 |
list_add_tail(&object->gray_list, &gray_list); } spin_unlock_irqrestore(&object->lock, flags); } rcu_read_unlock(); |
04609ccc4
|
1502 1503 1504 1505 |
/* * Re-scan the gray list for modified unreferenced objects. */ scan_gray_list(); |
4698c1f2b
|
1506 1507 |
/* |
04609ccc4
|
1508 |
* If scanning was stopped do not report any new unreferenced objects. |
17bb9e0d9
|
1509 |
*/ |
04609ccc4
|
1510 |
if (scan_should_stop()) |
17bb9e0d9
|
1511 1512 1513 |
return; /* |
4698c1f2b
|
1514 1515 1516 1517 1518 1519 1520 1521 |
* 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; |
154221c3e
|
1522 1523 1524 |
if (kmemleak_verbose) print_unreferenced(NULL, object); |
4698c1f2b
|
1525 1526 1527 1528 1529 |
new_leaks++; } spin_unlock_irqrestore(&object->lock, flags); } rcu_read_unlock(); |
dc9b3f424
|
1530 1531 |
if (new_leaks) { kmemleak_found_leaks = true; |
756a025f0
|
1532 1533 1534 |
pr_info("%d new suspected memory leaks (see /sys/kernel/debug/kmemleak) ", new_leaks); |
dc9b3f424
|
1535 |
} |
4698c1f2b
|
1536 |
|
3c7b4e6b8
|
1537 1538 1539 1540 1541 1542 1543 1544 |
} /* * 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) { |
d53ce0422
|
1545 |
static int first_run = IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN); |
3c7b4e6b8
|
1546 |
|
ae281064b
|
1547 1548 |
pr_info("Automatic memory scanning thread started "); |
bf2a76b31
|
1549 |
set_user_nice(current, 10); |
3c7b4e6b8
|
1550 1551 1552 1553 1554 |
/* * Wait before the first scan to allow the system to fully initialize. */ if (first_run) { |
98c42d945
|
1555 |
signed long timeout = msecs_to_jiffies(SECS_FIRST_SCAN * 1000); |
3c7b4e6b8
|
1556 |
first_run = 0; |
98c42d945
|
1557 1558 |
while (timeout && !kthread_should_stop()) timeout = schedule_timeout_interruptible(timeout); |
3c7b4e6b8
|
1559 1560 1561 |
} while (!kthread_should_stop()) { |
3c7b4e6b8
|
1562 1563 1564 |
signed long timeout = jiffies_scan_wait; mutex_lock(&scan_mutex); |
3c7b4e6b8
|
1565 |
kmemleak_scan(); |
3c7b4e6b8
|
1566 |
mutex_unlock(&scan_mutex); |
4698c1f2b
|
1567 |
|
3c7b4e6b8
|
1568 1569 1570 1571 |
/* wait before the next scan */ while (timeout && !kthread_should_stop()) timeout = schedule_timeout_interruptible(timeout); } |
ae281064b
|
1572 1573 |
pr_info("Automatic memory scanning thread ended "); |
3c7b4e6b8
|
1574 1575 1576 1577 1578 1579 |
return 0; } /* * Start the automatic memory scanning thread. This function must be called |
4698c1f2b
|
1580 |
* with the scan_mutex held. |
3c7b4e6b8
|
1581 |
*/ |
7eb0d5e5b
|
1582 |
static void start_scan_thread(void) |
3c7b4e6b8
|
1583 1584 1585 1586 1587 |
{ if (scan_thread) return; scan_thread = kthread_run(kmemleak_scan_thread, NULL, "kmemleak"); if (IS_ERR(scan_thread)) { |
598d80914
|
1588 1589 |
pr_warn("Failed to create the scan thread "); |
3c7b4e6b8
|
1590 1591 1592 1593 1594 |
scan_thread = NULL; } } /* |
914b6dfff
|
1595 |
* Stop the automatic memory scanning thread. |
3c7b4e6b8
|
1596 |
*/ |
7eb0d5e5b
|
1597 |
static void stop_scan_thread(void) |
3c7b4e6b8
|
1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 |
{ 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; |
b87324d08
|
1614 1615 1616 1617 1618 |
int err; err = mutex_lock_interruptible(&scan_mutex); if (err < 0) return ERR_PTR(err); |
3c7b4e6b8
|
1619 |
|
3c7b4e6b8
|
1620 1621 1622 1623 1624 1625 1626 1627 1628 |
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: |
3c7b4e6b8
|
1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 |
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; |
58fac0956
|
1640 |
struct kmemleak_object *obj = prev_obj; |
3c7b4e6b8
|
1641 1642 |
++(*pos); |
3c7b4e6b8
|
1643 |
|
58fac0956
|
1644 |
list_for_each_entry_continue_rcu(obj, &object_list, object_list) { |
52c3ce4ec
|
1645 1646 |
if (get_object(obj)) { next_obj = obj; |
3c7b4e6b8
|
1647 |
break; |
52c3ce4ec
|
1648 |
} |
3c7b4e6b8
|
1649 |
} |
288c857d6
|
1650 |
|
3c7b4e6b8
|
1651 1652 1653 1654 1655 1656 1657 1658 1659 |
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) { |
b87324d08
|
1660 1661 1662 1663 1664 |
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. */ |
f5886c7f9
|
1665 |
rcu_read_unlock(); |
b87324d08
|
1666 1667 1668 1669 |
mutex_unlock(&scan_mutex); if (v) put_object(v); } |
3c7b4e6b8
|
1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 |
} /* * 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); |
288c857d6
|
1681 |
if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) |
17bb9e0d9
|
1682 |
print_unreferenced(seq, object); |
3c7b4e6b8
|
1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 |
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) { |
b87324d08
|
1696 |
return seq_open(file, &kmemleak_seq_ops); |
3c7b4e6b8
|
1697 |
} |
189d84ed5
|
1698 1699 1700 1701 1702 |
static int dump_str_object_info(const char *str) { unsigned long flags; struct kmemleak_object *object; unsigned long addr; |
dc053733e
|
1703 1704 |
if (kstrtoul(str, 0, &addr)) return -EINVAL; |
189d84ed5
|
1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 |
object = find_and_get_object(addr, 0); if (!object) { pr_info("Unknown object at 0x%08lx ", addr); return -EINVAL; } spin_lock_irqsave(&object->lock, flags); dump_object_info(object); spin_unlock_irqrestore(&object->lock, flags); put_object(object); return 0; } |
3c7b4e6b8
|
1719 |
/* |
30b371010
|
1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 |
* 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)) |
a1084c877
|
1735 |
__paint_it(object, KMEMLEAK_GREY); |
30b371010
|
1736 1737 1738 |
spin_unlock_irqrestore(&object->lock, flags); } rcu_read_unlock(); |
dc9b3f424
|
1739 1740 |
kmemleak_found_leaks = false; |
30b371010
|
1741 |
} |
c89da70c7
|
1742 |
static void __kmemleak_do_cleanup(void); |
30b371010
|
1743 |
/* |
3c7b4e6b8
|
1744 1745 1746 1747 1748 1749 1750 1751 1752 |
* 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) |
4698c1f2b
|
1753 |
* scan - trigger a memory scan |
30b371010
|
1754 |
* clear - mark all current reported unreferenced kmemleak objects as |
c89da70c7
|
1755 1756 |
* grey to ignore printing them, or free all kmemleak objects * if kmemleak has been disabled. |
189d84ed5
|
1757 |
* dump=... - dump information about the object found at the given address |
3c7b4e6b8
|
1758 1759 1760 1761 1762 1763 |
*/ 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; |
b87324d08
|
1764 |
int ret; |
3c7b4e6b8
|
1765 1766 1767 1768 1769 |
buf_size = min(size, (sizeof(buf) - 1)); if (strncpy_from_user(buf, user_buf, buf_size) < 0) return -EFAULT; buf[buf_size] = 0; |
b87324d08
|
1770 1771 1772 |
ret = mutex_lock_interruptible(&scan_mutex); if (ret < 0) return ret; |
c89da70c7
|
1773 |
if (strncmp(buf, "clear", 5) == 0) { |
8910ae896
|
1774 |
if (kmemleak_enabled) |
c89da70c7
|
1775 1776 1777 1778 1779 |
kmemleak_clear(); else __kmemleak_do_cleanup(); goto out; } |
8910ae896
|
1780 |
if (!kmemleak_enabled) { |
4e4dfce22
|
1781 |
ret = -EPERM; |
c89da70c7
|
1782 1783 |
goto out; } |
3c7b4e6b8
|
1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 |
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; |
3c7b4e6b8
|
1796 |
|
3dbb95f78
|
1797 |
ret = kstrtoul(buf + 5, 0, &secs); |
b87324d08
|
1798 1799 |
if (ret < 0) goto out; |
3c7b4e6b8
|
1800 1801 1802 1803 1804 |
stop_scan_thread(); if (secs) { jiffies_scan_wait = msecs_to_jiffies(secs * 1000); start_scan_thread(); } |
4698c1f2b
|
1805 1806 |
} else if (strncmp(buf, "scan", 4) == 0) kmemleak_scan(); |
189d84ed5
|
1807 1808 |
else if (strncmp(buf, "dump=", 5) == 0) ret = dump_str_object_info(buf + 5); |
4698c1f2b
|
1809 |
else |
b87324d08
|
1810 1811 1812 1813 1814 1815 |
ret = -EINVAL; out: mutex_unlock(&scan_mutex); if (ret < 0) return ret; |
3c7b4e6b8
|
1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 |
/* 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, |
5f3bf19ae
|
1828 |
.release = seq_release, |
3c7b4e6b8
|
1829 |
}; |
c89da70c7
|
1830 1831 |
static void __kmemleak_do_cleanup(void) { |
2abd839aa
|
1832 |
struct kmemleak_object *object, *tmp; |
c89da70c7
|
1833 |
|
2abd839aa
|
1834 1835 1836 1837 1838 1839 1840 1841 |
/* * Kmemleak has already been disabled, no need for RCU list traversal * or kmemleak_lock held. */ list_for_each_entry_safe(object, tmp, &object_list, object_list) { __remove_object(object); __delete_object(object); } |
c89da70c7
|
1842 |
} |
3c7b4e6b8
|
1843 |
/* |
74341703e
|
1844 1845 1846 |
* 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). |
3c7b4e6b8
|
1847 |
*/ |
179a8100e
|
1848 |
static void kmemleak_do_cleanup(struct work_struct *work) |
3c7b4e6b8
|
1849 |
{ |
3c7b4e6b8
|
1850 |
stop_scan_thread(); |
3c7b4e6b8
|
1851 |
|
914b6dfff
|
1852 |
mutex_lock(&scan_mutex); |
c5f3b1a51
|
1853 |
/* |
914b6dfff
|
1854 1855 1856 1857 |
* 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. |
c5f3b1a51
|
1858 1859 |
*/ kmemleak_free_enabled = 0; |
914b6dfff
|
1860 |
mutex_unlock(&scan_mutex); |
c5f3b1a51
|
1861 |
|
c89da70c7
|
1862 1863 1864 |
if (!kmemleak_found_leaks) __kmemleak_do_cleanup(); else |
756a025f0
|
1865 1866 |
pr_info("Kmemleak disabled without freeing internal data. Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\". "); |
3c7b4e6b8
|
1867 |
} |
179a8100e
|
1868 |
static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup); |
3c7b4e6b8
|
1869 1870 1871 1872 1873 1874 1875 1876 |
/* * 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 */ |
8910ae896
|
1877 |
if (cmpxchg(&kmemleak_error, 0, 1)) |
3c7b4e6b8
|
1878 1879 1880 |
return; /* stop any memory operation tracing */ |
8910ae896
|
1881 |
kmemleak_enabled = 0; |
3c7b4e6b8
|
1882 1883 |
/* check whether it is too early for a kernel thread */ |
8910ae896
|
1884 |
if (kmemleak_initialized) |
179a8100e
|
1885 |
schedule_work(&cleanup_work); |
c5f3b1a51
|
1886 1887 |
else kmemleak_free_enabled = 0; |
3c7b4e6b8
|
1888 1889 1890 1891 1892 1893 1894 1895 |
pr_info("Kernel memory leak detector disabled "); } /* * Allow boot-time kmemleak disabling (enabled by default). */ |
8bd30c109
|
1896 |
static int __init kmemleak_boot_config(char *str) |
3c7b4e6b8
|
1897 1898 1899 1900 1901 |
{ if (!str) return -EINVAL; if (strcmp(str, "off") == 0) kmemleak_disable(); |
ab0155a22
|
1902 1903 1904 |
else if (strcmp(str, "on") == 0) kmemleak_skip_disable = 1; else |
3c7b4e6b8
|
1905 1906 1907 1908 1909 1910 |
return -EINVAL; return 0; } early_param("kmemleak", kmemleak_boot_config); /* |
2030117d2
|
1911 |
* Kmemleak initialization. |
3c7b4e6b8
|
1912 1913 1914 |
*/ void __init kmemleak_init(void) { |
ab0155a22
|
1915 1916 1917 1918 1919 1920 |
#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF if (!kmemleak_skip_disable) { kmemleak_disable(); return; } #endif |
c56658681
|
1921 1922 |
if (kmemleak_error) return; |
3c7b4e6b8
|
1923 1924 1925 1926 1927 |
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); |
3c7b4e6b8
|
1928 |
|
298a32b13
|
1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 |
/* register the data/bss sections */ create_object((unsigned long)_sdata, _edata - _sdata, KMEMLEAK_GREY, GFP_ATOMIC); create_object((unsigned long)__bss_start, __bss_stop - __bss_start, KMEMLEAK_GREY, GFP_ATOMIC); /* only register .data..ro_after_init if not within .data */ if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata) create_object((unsigned long)__start_ro_after_init, __end_ro_after_init - __start_ro_after_init, KMEMLEAK_GREY, GFP_ATOMIC); |
3c7b4e6b8
|
1939 1940 1941 1942 1943 1944 1945 |
} /* * Late initialization function. */ static int __init kmemleak_late_init(void) { |
8910ae896
|
1946 |
kmemleak_initialized = 1; |
3c7b4e6b8
|
1947 |
|
282401df9
|
1948 |
debugfs_create_file("kmemleak", 0644, NULL, NULL, &kmemleak_fops); |
b353756b2
|
1949 |
|
8910ae896
|
1950 |
if (kmemleak_error) { |
3c7b4e6b8
|
1951 |
/* |
25985edce
|
1952 |
* Some error occurred and kmemleak was disabled. There is a |
3c7b4e6b8
|
1953 1954 1955 1956 |
* 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. */ |
179a8100e
|
1957 |
schedule_work(&cleanup_work); |
3c7b4e6b8
|
1958 1959 |
return -ENOMEM; } |
d53ce0422
|
1960 1961 1962 1963 1964 |
if (IS_ENABLED(CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN)) { mutex_lock(&scan_mutex); start_scan_thread(); mutex_unlock(&scan_mutex); } |
3c7b4e6b8
|
1965 |
|
0e965a6bd
|
1966 1967 1968 |
pr_info("Kernel memory leak detector initialized (mem pool available: %d) ", mem_pool_free_count); |
3c7b4e6b8
|
1969 1970 1971 1972 |
return 0; } late_initcall(kmemleak_late_init); |