kmemleak: Do not acquire scan_mutex in kmemleak_open()
Initially, the scan_mutex was acquired in kmemleak_open() and released in kmemleak_release() (corresponding to /sys/kernel/debug/kmemleak operations). This was causing some lockdep reports when the file was closed from a different task than the one opening it. This patch moves the scan_mutex acquiring in kmemleak_write() or kmemleak_seq_start() with releasing in kmemleak_seq_stop(). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>hifive-unleashed-5.1
parent
288c857d66
commit
b87324d082
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@ -1101,6 +1101,11 @@ static void *kmemleak_seq_start(struct seq_file *seq, loff_t *pos)
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{
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{
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struct kmemleak_object *object;
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struct kmemleak_object *object;
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loff_t n = *pos;
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loff_t n = *pos;
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int err;
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err = mutex_lock_interruptible(&scan_mutex);
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if (err < 0)
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return ERR_PTR(err);
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rcu_read_lock();
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rcu_read_lock();
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list_for_each_entry_rcu(object, &object_list, object_list) {
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list_for_each_entry_rcu(object, &object_list, object_list) {
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@ -1144,8 +1149,15 @@ static void *kmemleak_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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*/
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*/
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static void kmemleak_seq_stop(struct seq_file *seq, void *v)
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static void kmemleak_seq_stop(struct seq_file *seq, void *v)
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{
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{
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if (v)
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if (!IS_ERR(v)) {
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put_object(v);
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/*
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* kmemleak_seq_start may return ERR_PTR if the scan_mutex
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* waiting was interrupted, so only release it if !IS_ERR.
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*/
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mutex_unlock(&scan_mutex);
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if (v)
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put_object(v);
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}
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}
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}
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/*
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/*
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@ -1172,36 +1184,15 @@ static const struct seq_operations kmemleak_seq_ops = {
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static int kmemleak_open(struct inode *inode, struct file *file)
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static int kmemleak_open(struct inode *inode, struct file *file)
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{
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{
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int ret = 0;
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if (!atomic_read(&kmemleak_enabled))
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if (!atomic_read(&kmemleak_enabled))
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return -EBUSY;
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return -EBUSY;
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ret = mutex_lock_interruptible(&scan_mutex);
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return seq_open(file, &kmemleak_seq_ops);
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if (ret < 0)
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goto out;
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if (file->f_mode & FMODE_READ) {
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ret = seq_open(file, &kmemleak_seq_ops);
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if (ret < 0)
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goto scan_unlock;
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}
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return ret;
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scan_unlock:
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mutex_unlock(&scan_mutex);
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out:
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return ret;
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}
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}
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static int kmemleak_release(struct inode *inode, struct file *file)
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static int kmemleak_release(struct inode *inode, struct file *file)
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{
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{
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int ret = 0;
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return seq_release(inode, file);
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if (file->f_mode & FMODE_READ)
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seq_release(inode, file);
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mutex_unlock(&scan_mutex);
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return ret;
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}
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}
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/*
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/*
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@ -1221,15 +1212,17 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
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{
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{
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char buf[64];
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char buf[64];
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int buf_size;
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int buf_size;
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int ret;
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if (!atomic_read(&kmemleak_enabled))
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return -EBUSY;
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buf_size = min(size, (sizeof(buf) - 1));
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buf_size = min(size, (sizeof(buf) - 1));
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if (strncpy_from_user(buf, user_buf, buf_size) < 0)
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if (strncpy_from_user(buf, user_buf, buf_size) < 0)
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return -EFAULT;
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return -EFAULT;
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buf[buf_size] = 0;
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buf[buf_size] = 0;
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ret = mutex_lock_interruptible(&scan_mutex);
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if (ret < 0)
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return ret;
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if (strncmp(buf, "off", 3) == 0)
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if (strncmp(buf, "off", 3) == 0)
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kmemleak_disable();
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kmemleak_disable();
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else if (strncmp(buf, "stack=on", 8) == 0)
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else if (strncmp(buf, "stack=on", 8) == 0)
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@ -1242,11 +1235,10 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
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stop_scan_thread();
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stop_scan_thread();
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else if (strncmp(buf, "scan=", 5) == 0) {
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else if (strncmp(buf, "scan=", 5) == 0) {
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unsigned long secs;
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unsigned long secs;
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int err;
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err = strict_strtoul(buf + 5, 0, &secs);
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ret = strict_strtoul(buf + 5, 0, &secs);
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if (err < 0)
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if (ret < 0)
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return err;
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goto out;
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stop_scan_thread();
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stop_scan_thread();
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if (secs) {
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if (secs) {
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jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
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jiffies_scan_wait = msecs_to_jiffies(secs * 1000);
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@ -1255,7 +1247,12 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
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} else if (strncmp(buf, "scan", 4) == 0)
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} else if (strncmp(buf, "scan", 4) == 0)
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kmemleak_scan();
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kmemleak_scan();
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else
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else
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return -EINVAL;
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ret = -EINVAL;
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out:
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mutex_unlock(&scan_mutex);
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if (ret < 0)
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return ret;
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/* ignore the rest of the buffer, only one command at a time */
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/* ignore the rest of the buffer, only one command at a time */
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*ppos += size;
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*ppos += size;
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