diff options
Diffstat (limited to 'mm/kmemleak.c')
| -rw-r--r-- | mm/kmemleak.c | 90 |
1 files changed, 40 insertions, 50 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 4130a4889fa9..e96e0ec6a56e 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 @@ -195,10 +195,8 @@ static unsigned long jiffies_min_age; static signed long jiffies_scan_wait; /* enables or disables the task stacks scanning */ static int kmemleak_stack_scan = 1; -/* mutex protecting the memory scanning */ +/* 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; @@ -927,6 +925,7 @@ static void kmemleak_scan(void) struct kmemleak_object *object, *tmp; struct task_struct *task; int i; + int new_leaks = 0; /* prepare the kmemleak_object's */ rcu_read_lock(); @@ -1024,6 +1023,26 @@ static void kmemleak_scan(void) object = tmp; } WARN_ON(!list_empty(&gray_list)); + + /* + * 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); + } /* @@ -1045,33 +1064,12 @@ static int kmemleak_scan_thread(void *arg) } while (!kthread_should_stop()) { - struct kmemleak_object *object; signed long timeout = jiffies_scan_wait; - int new_leaks = 0; mutex_lock(&scan_mutex); - kmemleak_scan(); - - rcu_read_lock(); - list_for_each_entry_rcu(object, &object_list, object_list) { - unsigned long flags; - - 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); - mutex_unlock(&scan_mutex); + /* wait before the next scan */ while (timeout && !kthread_should_stop()) timeout = schedule_timeout_interruptible(timeout); @@ -1084,7 +1082,7 @@ 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) { @@ -1099,7 +1097,7 @@ 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) { @@ -1119,10 +1117,8 @@ 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; @@ -1206,13 +1202,10 @@ 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; @@ -1221,8 +1214,6 @@ 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; } @@ -1231,11 +1222,9 @@ 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; } @@ -1250,6 +1239,7 @@ 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) @@ -1287,7 +1277,9 @@ 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 */ @@ -1312,11 +1304,9 @@ 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); @@ -1458,9 +1448,9 @@ 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"); |
