tracing: Miscellaneous fixes for trace_array ref counting

Some error paths did not handle ref counting properly, and some trace files need
ref counting.

Link: http://lkml.kernel.org/r/1374171524-11948-1-git-send-email-azl@google.com
Cc: stable@vger.kernel.org # 3.10
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7c3da7b..7d9ceab 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3008,7 +3008,6 @@ static int tracing_release(struct inode *inode, struct file *file)
 
        iter = m->private;
        tr = iter->tr;
-       trace_array_put(tr);
 
        mutex_lock(&trace_types_lock);
 
@@ -3023,6 +3022,9 @@ static int tracing_release(struct inode *inode, struct file *file)
        if (!iter->snapshot)
                /* reenable tracing if it was previously enabled */
                tracing_start_tr(tr);
+
+       __trace_array_put(tr);
+
        mutex_unlock(&trace_types_lock);
 
        mutex_destroy(&iter->mutex);
@@ -3447,6 +3449,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
 static int tracing_trace_options_open(struct inode *inode, struct file *file)
 {
        struct trace_array *tr = inode->i_private;
+       int ret;
 
        if (tracing_disabled)
                return -ENODEV;
@@ -3454,7 +3457,11 @@ static int tracing_trace_options_open(struct inode *inode, struct file *file)
        if (trace_array_get(tr) < 0)
                return -ENODEV;
 
-       return single_open(file, tracing_trace_options_show, inode->i_private);
+       ret = single_open(file, tracing_trace_options_show, inode->i_private);
+       if (ret < 0)
+               trace_array_put(tr);
+
+       return ret;
 }
 
 static const struct file_operations tracing_iter_fops = {
@@ -3958,6 +3965,7 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
        iter = kzalloc(sizeof(*iter), GFP_KERNEL);
        if (!iter) {
                ret = -ENOMEM;
+               __trace_array_put(tr);
                goto out;
        }
 
@@ -4704,21 +4712,24 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file)
                        ret = PTR_ERR(iter);
        } else {
                /* Writes still need the seq_file to hold the private data */
+               ret = -ENOMEM;
                m = kzalloc(sizeof(*m), GFP_KERNEL);
                if (!m)
-                       return -ENOMEM;
+                       goto out;
                iter = kzalloc(sizeof(*iter), GFP_KERNEL);
                if (!iter) {
                        kfree(m);
-                       return -ENOMEM;
+                       goto out;
                }
+               ret = 0;
+
                iter->tr = tr;
                iter->trace_buffer = &tc->tr->max_buffer;
                iter->cpu_file = tc->cpu;
                m->private = iter;
                file->private_data = m;
        }
-
+out:
        if (ret < 0)
                trace_array_put(tr);
 
@@ -5328,9 +5339,10 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
 }
 
 static const struct file_operations tracing_stats_fops = {
-       .open           = tracing_open_generic,
+       .open           = tracing_open_generic_tc,
        .read           = tracing_stats_read,
        .llseek         = generic_file_llseek,
+       .release        = tracing_release_generic_tc,
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 7d85429..7a75cb2 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1218,6 +1218,7 @@ show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
 
 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
 static int ftrace_event_set_open(struct inode *inode, struct file *file);
+static int ftrace_event_release(struct inode *inode, struct file *file);
 
 static const struct seq_operations show_event_seq_ops = {
        .start = t_start,
@@ -1245,7 +1246,7 @@ static const struct file_operations ftrace_set_event_fops = {
        .read = seq_read,
        .write = ftrace_event_write,
        .llseek = seq_lseek,
-       .release = seq_release,
+       .release = ftrace_event_release,
 };
 
 static const struct file_operations ftrace_enable_fops = {
@@ -1323,6 +1324,15 @@ ftrace_event_open(struct inode *inode, struct file *file,
        return ret;
 }
 
+static int ftrace_event_release(struct inode *inode, struct file *file)
+{
+       struct trace_array *tr = inode->i_private;
+
+       trace_array_put(tr);
+
+       return seq_release(inode, file);
+}
+
 static int
 ftrace_event_avail_open(struct inode *inode, struct file *file)
 {
@@ -1336,12 +1346,19 @@ ftrace_event_set_open(struct inode *inode, struct file *file)
 {
        const struct seq_operations *seq_ops = &show_set_event_seq_ops;
        struct trace_array *tr = inode->i_private;
+       int ret;
+
+       if (trace_array_get(tr) < 0)
+               return -ENODEV;
 
        if ((file->f_mode & FMODE_WRITE) &&
            (file->f_flags & O_TRUNC))
                ftrace_clear_events(tr);
 
-       return ftrace_event_open(inode, file, seq_ops);
+       ret = ftrace_event_open(inode, file, seq_ops);
+       if (ret < 0)
+               trace_array_put(tr);
+       return ret;
 }
 
 static struct event_subsystem *