tracing: Change tracing_stats_fops to rely on tracing_get_cpu()
tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.
1. Change one of its users, tracing_stats_fops, to use
tracing_*_generic_tr() instead.
2. Change trace_create_cpu_file("stats", data) to pass "data = tr".
3. Change tracing_stats_read() to use tracing_get_cpu().
Link: http://lkml.kernel.org/r/20130723152603.GA23727@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 30c058a..e29dc8f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2982,7 +2982,6 @@
filp->private_data = inode->i_private;
return 0;
-
}
static int tracing_open_generic_tc(struct inode *inode, struct file *filp)
@@ -5285,14 +5284,14 @@
tracing_stats_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
- struct trace_cpu *tc = filp->private_data;
- struct trace_array *tr = tc->tr;
+ struct inode *inode = file_inode(filp);
+ struct trace_array *tr = inode->i_private;
struct trace_buffer *trace_buf = &tr->trace_buffer;
+ int cpu = tracing_get_cpu(inode);
struct trace_seq *s;
unsigned long cnt;
unsigned long long t;
unsigned long usec_rem;
- int cpu = tc->cpu;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
@@ -5345,10 +5344,10 @@
}
static const struct file_operations tracing_stats_fops = {
- .open = tracing_open_generic_tc,
+ .open = tracing_open_generic_tr,
.read = tracing_stats_read,
.llseek = generic_file_llseek,
- .release = tracing_release_generic_tc,
+ .release = tracing_release_generic_tr,
};
#ifdef CONFIG_DYNAMIC_FTRACE
@@ -5578,7 +5577,7 @@
tr, cpu, &tracing_buffers_fops);
trace_create_cpu_file("stats", 0444, d_cpu,
- &data->trace_cpu, cpu, &tracing_stats_fops);
+ tr, cpu, &tracing_stats_fops);
trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
&data->trace_cpu, cpu, &tracing_entries_fops);