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Subject[ 19/99] tracing: Miscellaneous fixes for trace_array ref counting
Date
3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Z Lam <azl@google.com>

commit f77d09a384676bde6445413949d9d2c508ff3e62 upstream.

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

Signed-off-by: Alexander Z Lam <azl@google.com>
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/trace/trace.c | 24 ++++++++++++++++++------
kernel/trace/trace_events.c | 21 +++++++++++++++++++--
2 files changed, 37 insertions(+), 8 deletions(-)

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2956,7 +2956,6 @@ static int tracing_release(struct inode

iter = m->private;
tr = iter->tr;
- trace_array_put(tr);

mutex_lock(&trace_types_lock);

@@ -2971,6 +2970,9 @@ static int tracing_release(struct inode
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);
@@ -3395,6 +3397,7 @@ tracing_trace_options_write(struct file
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;
@@ -3402,7 +3405,11 @@ static int tracing_trace_options_open(st
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 = {
@@ -3906,6 +3913,7 @@ static int tracing_open_pipe(struct inod
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
if (!iter) {
ret = -ENOMEM;
+ __trace_array_put(tr);
goto out;
}

@@ -4652,21 +4660,24 @@ static int tracing_snapshot_open(struct
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);

@@ -5276,9 +5287,10 @@ tracing_stats_read(struct file *filp, ch
}

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
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1221,6 +1221,7 @@ show_header(struct file *filp, char __us

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,
@@ -1248,7 +1249,7 @@ static const struct file_operations ftra
.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 = {
@@ -1326,6 +1327,15 @@ ftrace_event_open(struct inode *inode, s
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)
{
@@ -1339,12 +1349,19 @@ ftrace_event_set_open(struct inode *inod
{
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 *



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