diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/kmemleak.c | 166 |
1 files changed, 70 insertions, 96 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index c96f2c8..eeece2d 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -48,10 +48,10 @@ * 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 - * - kmemleak_mutex (mutex): prevents multiple users of the "kmemleak" debugfs - * file together with modifications to the memory scanning parameters - * including the scan_thread pointer + * 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 * * The kmemleak_object structures have a use_count incremented or decremented * using the get_object()/put_object() functions. When the use_count becomes @@ -190,15 +190,15 @@ static unsigned long max_addr; static unsigned long next_scan_yield; static struct task_struct *scan_thread; static unsigned long jiffies_scan_yield; +/* 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; -/* mutex protecting the memory scanning */ +static int kmemleak_stack_scan = 1; +/* protects the memory scanning, parameters and debug/kmemleak file access */ static DEFINE_MUTEX(scan_mutex); -/* mutex protecting the access to the /sys/kernel/debug/kmemleak file */ -static DEFINE_MUTEX(kmemleak_mutex); /* number of leaks reported (for limitation purposes) */ static int reported_leaks; @@ -235,7 +235,7 @@ struct early_log { }; /* early logging buffer and current position */ -static struct early_log early_log[200]; +static struct early_log early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE]; static int crt_early_log; static void kmemleak_disable(void); @@ -279,15 +279,6 @@ static int color_gray(const struct kmemleak_object *object) } /* - * Objects are considered referenced if their color is gray and they have not - * been deleted. - */ -static int referenced_object(struct kmemleak_object *object) -{ - return (object->flags & OBJECT_ALLOCATED) && color_gray(object); -} - -/* * 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. @@ -295,42 +286,28 @@ static int referenced_object(struct kmemleak_object *object) static int unreferenced_object(struct kmemleak_object *object) { return (object->flags & OBJECT_ALLOCATED) && color_white(object) && - time_is_before_eq_jiffies(object->jiffies + jiffies_min_age); + time_before_eq(object->jiffies + jiffies_min_age, + jiffies_last_scan); } /* - * Printing of the (un)referenced objects information, either to the seq file - * or to the kernel log. The print_referenced/print_unreferenced functions - * must be called with the object->lock held. + * Printing of the unreferenced objects information to the seq file. The + * print_unreferenced function must be called with the object->lock held. */ -#define print_helper(seq, x...) do { \ - struct seq_file *s = (seq); \ - if (s) \ - seq_printf(s, x); \ - else \ - pr_info(x); \ -} while (0) - -static void print_referenced(struct kmemleak_object *object) -{ - pr_info("referenced object 0x%08lx (size %zu)\n", - object->pointer, object->size); -} - static void print_unreferenced(struct seq_file *seq, struct kmemleak_object *object) { int i; - print_helper(seq, "unreferenced object 0x%08lx (size %zu):\n", - object->pointer, object->size); - print_helper(seq, " comm \"%s\", pid %d, jiffies %lu\n", - object->comm, object->pid, object->jiffies); - print_helper(seq, " backtrace:\n"); + seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", + object->pointer, object->size); + seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", + object->comm, object->pid, object->jiffies); + seq_printf(seq, " backtrace:\n"); for (i = 0; i < object->trace_len; i++) { void *ptr = (void *)object->trace[i]; - print_helper(seq, " [<%p>] %pS\n", ptr, ptr); + seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); } } @@ -554,8 +531,10 @@ static void delete_object(unsigned long ptr) write_lock_irqsave(&kmemleak_lock, flags); object = lookup_object(ptr, 0); if (!object) { +#ifdef DEBUG kmemleak_warn("Freeing unknown object at 0x%08lx\n", ptr); +#endif write_unlock_irqrestore(&kmemleak_lock, flags); return; } @@ -571,8 +550,6 @@ static void delete_object(unsigned long ptr) * cannot be freed when it is being scanned. */ spin_lock_irqsave(&object->lock, flags); - if (object->flags & OBJECT_REPORTED) - print_referenced(object); object->flags &= ~OBJECT_ALLOCATED; spin_unlock_irqrestore(&object->lock, flags); put_object(object); @@ -696,7 +673,8 @@ static void log_early(int op_type, const void *ptr, size_t size, struct early_log *log; if (crt_early_log >= ARRAY_SIZE(early_log)) { - kmemleak_stop("Early log buffer exceeded\n"); + pr_warning("Early log buffer exceeded\n"); + kmemleak_disable(); return; } @@ -952,6 +930,9 @@ static void kmemleak_scan(void) struct kmemleak_object *object, *tmp; struct task_struct *task; int i; + int new_leaks = 0; + + jiffies_last_scan = jiffies; /* prepare the kmemleak_object's */ rcu_read_lock(); @@ -1049,6 +1030,32 @@ static void kmemleak_scan(void) object = tmp; } WARN_ON(!list_empty(&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) + pr_info("%d new suspected memory leaks (see " + "/sys/kernel/debug/kmemleak)\n", new_leaks); + } /* @@ -1070,36 +1077,12 @@ static int kmemleak_scan_thread(void *arg) } while (!kthread_should_stop()) { - struct kmemleak_object *object; signed long timeout = jiffies_scan_wait; mutex_lock(&scan_mutex); - kmemleak_scan(); - reported_leaks = 0; - - rcu_read_lock(); - list_for_each_entry_rcu(object, &object_list, object_list) { - unsigned long flags; - - if (reported_leaks >= REPORTS_NR) - break; - spin_lock_irqsave(&object->lock, flags); - if (!(object->flags & OBJECT_REPORTED) && - unreferenced_object(object)) { - print_unreferenced(NULL, object); - object->flags |= OBJECT_REPORTED; - reported_leaks++; - } else if ((object->flags & OBJECT_REPORTED) && - referenced_object(object)) { - print_referenced(object); - object->flags &= ~OBJECT_REPORTED; - } - spin_unlock_irqrestore(&object->lock, flags); - } - rcu_read_unlock(); - mutex_unlock(&scan_mutex); + /* wait before the next scan */ while (timeout && !kthread_should_stop()) timeout = schedule_timeout_interruptible(timeout); @@ -1112,7 +1095,7 @@ static int kmemleak_scan_thread(void *arg) /* * Start the automatic memory scanning thread. This function must be called - * with the kmemleak_mutex held. + * with the scan_mutex held. */ void start_scan_thread(void) { @@ -1127,7 +1110,7 @@ void start_scan_thread(void) /* * Stop the automatic memory scanning thread. This function must be called - * with the kmemleak_mutex held. + * with the scan_mutex held. */ void stop_scan_thread(void) { @@ -1147,10 +1130,8 @@ static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos) struct kmemleak_object *object; loff_t n = *pos; - if (!n) { - kmemleak_scan(); + if (!n) reported_leaks = 0; - } if (reported_leaks >= REPORTS_NR) return NULL; @@ -1211,11 +1192,10 @@ static int kmemleak_seq_show(struct seq_file *seq, void *v) unsigned long flags; spin_lock_irqsave(&object->lock, flags); - if (!unreferenced_object(object)) - goto out; - print_unreferenced(seq, object); - reported_leaks++; -out: + if ((object->flags & OBJECT_REPORTED) && unreferenced_object(object)) { + print_unreferenced(seq, object); + reported_leaks++; + } spin_unlock_irqrestore(&object->lock, flags); return 0; } @@ -1234,13 +1214,10 @@ static int kmemleak_open(struct inode *inode, struct file *file) if (!atomic_read(&kmemleak_enabled)) return -EBUSY; - ret = mutex_lock_interruptible(&kmemleak_mutex); + ret = mutex_lock_interruptible(&scan_mutex); if (ret < 0) goto out; if (file->f_mode & FMODE_READ) { - ret = mutex_lock_interruptible(&scan_mutex); - if (ret < 0) - goto kmemleak_unlock; ret = seq_open(file, &kmemleak_seq_ops); if (ret < 0) goto scan_unlock; @@ -1249,8 +1226,6 @@ static int kmemleak_open(struct inode *inode, struct file *file) scan_unlock: mutex_unlock(&scan_mutex); -kmemleak_unlock: - mutex_unlock(&kmemleak_mutex); out: return ret; } @@ -1259,11 +1234,9 @@ static int kmemleak_release(struct inode *inode, struct file *file) { int ret = 0; - if (file->f_mode & FMODE_READ) { + if (file->f_mode & FMODE_READ) seq_release(inode, file); - mutex_unlock(&scan_mutex); - } - mutex_unlock(&kmemleak_mutex); + mutex_unlock(&scan_mutex); return ret; } @@ -1278,6 +1251,7 @@ static int kmemleak_release(struct inode *inode, struct file *file) * 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 */ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, size_t size, loff_t *ppos) @@ -1315,7 +1289,9 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf, jiffies_scan_wait = msecs_to_jiffies(secs * 1000); start_scan_thread(); } - } else + } else if (strncmp(buf, "scan", 4) == 0) + kmemleak_scan(); + else return -EINVAL; /* ignore the rest of the buffer, only one command at a time */ @@ -1340,11 +1316,9 @@ static int kmemleak_cleanup_thread(void *arg) { struct kmemleak_object *object; - mutex_lock(&kmemleak_mutex); + mutex_lock(&scan_mutex); stop_scan_thread(); - mutex_unlock(&kmemleak_mutex); - mutex_lock(&scan_mutex); rcu_read_lock(); list_for_each_entry_rcu(object, &object_list, object_list) delete_object(object->pointer); @@ -1486,9 +1460,9 @@ static int __init kmemleak_late_init(void) &kmemleak_fops); if (!dentry) pr_warning("Failed to create the debugfs kmemleak file\n"); - mutex_lock(&kmemleak_mutex); + mutex_lock(&scan_mutex); start_scan_thread(); - mutex_unlock(&kmemleak_mutex); + mutex_unlock(&scan_mutex); pr_info("Kernel memory leak detector initialized\n"); |
