From: Oleg Nesterov <oleg@xxxxxxxxxx>
commit 15544209cb0b5312e5220a9337a1fe61d1a1f2d9 upstream.
tracing_open_pipe() is racy, the memory inode->i_private points to
can be already freed.
Change debugfs_create_file("trace_pipe", data) callers to to pass
"data = tr", tracing_open_pipe() can use tracing_get_cpu().
Link: http://lkml.kernel.org/r/20130723152557.GA23717@xxxxxxxxxx
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f064dfb..8e8bb0e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3950,8 +3950,7 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf,
static int tracing_open_pipe(struct inode *inode, struct file *filp)
{
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
+ struct trace_array *tr = inode->i_private;
struct trace_iterator *iter;
int ret = 0;
@@ -3997,9 +3996,9 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
if (trace_clocks[tr->clock_id].in_ns)
iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
- iter->cpu_file = tc->cpu;
- iter->tr = tc->tr;
- iter->trace_buffer = &tc->tr->trace_buffer;
+ iter->tr = tr;
+ iter->trace_buffer = &tr->trace_buffer;
+ iter->cpu_file = tracing_get_cpu(inode);
mutex_init(&iter->mutex);
filp->private_data = iter;
@@ -4022,8 +4021,7 @@ fail:
static int tracing_release_pipe(struct inode *inode, struct file *file)
{
struct trace_iterator *iter = file->private_data;
- struct trace_cpu *tc = inode->i_private;
- struct trace_array *tr = tc->tr;
+ struct trace_array *tr = inode->i_private;
mutex_lock(&trace_types_lock);
@@ -5563,7 +5561,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
/* per cpu trace_pipe */
trace_create_cpu_file("trace_pipe", 0444, d_cpu,
- &data->trace_cpu, cpu, &tracing_pipe_fops);
+ tr, cpu, &tracing_pipe_fops);
/* per cpu trace */
trace_create_cpu_file("trace", 0644, d_cpu,
@@ -6149,7 +6147,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
(void *)&tr->trace_cpu, &tracing_fops);
trace_create_file("trace_pipe", 0444, d_tracer,
- (void *)&tr->trace_cpu, &tracing_pipe_fops);
+ tr, &tracing_pipe_fops);
trace_create_file("buffer_size_kb", 0644, d_tracer,
(void *)&tr->trace_cpu, &tracing_entries_fops);
--
1.7.10.4
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