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tracing: Change tracing_entries_fops to rely on tracing_get_cpu()

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tracing_open_generic_tc() is racy, the memory inode->i_private
points to can be already freed.

1. Change its last user, tracing_entries_fops, to use
   tracing_*_generic_tr() instead.

2. Change debugfs_create_file("buffer_size_kb", data) callers
   to pass "data = tr".

3. Change tracing_entries_read() and tracing_entries_write() to
   use tracing_get_cpu().

4. Kill the no longer used tracing_open_generic_tc() and
   tracing_release_generic_tc().

Link: http://lkml.kernel.org/r/20130723152606.GA23730@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Oleg Nesterov 2013-07-23 17:26:06 +02:00 committed by Steven Rostedt
parent 4d3435b8a4
commit 0bc392ee46
1 changed files with 12 additions and 37 deletions
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49
kernel/trace/trace.c
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@ -2984,23 +2984,6 @@ static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
return 0;
}
static int tracing_open_generic_tc(struct inode *inode, struct file *filp)
{
struct trace_cpu *tc = inode->i_private;
struct trace_array *tr = tc->tr;
if (tracing_disabled)
return -ENODEV;
if (trace_array_get(tr) < 0)
return -ENODEV;
filp->private_data = inode->i_private;
return 0;
}
static int tracing_release(struct inode *inode, struct file *file)
{
struct seq_file *m = file->private_data;
@ -3054,15 +3037,6 @@ static int tracing_release_generic_tr(struct inode *inode, struct file *file)
return 0;
}
static int tracing_release_generic_tc(struct inode *inode, struct file *file)
{
struct trace_cpu *tc = inode->i_private;
struct trace_array *tr = tc->tr;
trace_array_put(tr);
return 0;
}
static int tracing_single_release_tr(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
@ -4382,15 +4356,16 @@ static ssize_t
tracing_entries_read(struct file *filp, char __user *ubuf,
size_t cnt, 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;
int cpu = tracing_get_cpu(inode);
char buf[64];
int r = 0;
ssize_t ret;
mutex_lock(&trace_types_lock);
if (tc->cpu == RING_BUFFER_ALL_CPUS) {
if (cpu == RING_BUFFER_ALL_CPUS) {
int cpu, buf_size_same;
unsigned long size;
@ -4417,7 +4392,7 @@ tracing_entries_read(struct file *filp, char __user *ubuf,
} else
r = sprintf(buf, "X\n");
} else
r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10);
r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
mutex_unlock(&trace_types_lock);
@ -4429,7 +4404,8 @@ static ssize_t
tracing_entries_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct trace_cpu *tc = filp->private_data;
struct inode *inode = file_inode(filp);
struct trace_array *tr = inode->i_private;
unsigned long val;
int ret;
@ -4443,8 +4419,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
/* value is in KB */
val <<= 10;
ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu);
ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
if (ret < 0)
return ret;
@ -4892,11 +4867,11 @@ static const struct file_operations tracing_pipe_fops = {
};
static const struct file_operations tracing_entries_fops = {
.open = tracing_open_generic_tc,
.open = tracing_open_generic_tr,
.read = tracing_entries_read,
.write = tracing_entries_write,
.llseek = generic_file_llseek,
.release = tracing_release_generic_tc,
.release = tracing_release_generic_tr,
};
static const struct file_operations tracing_total_entries_fops = {
@ -5580,7 +5555,7 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
tr, cpu, &tracing_stats_fops);
trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
&data->trace_cpu, cpu, &tracing_entries_fops);
tr, cpu, &tracing_entries_fops);
#ifdef CONFIG_TRACER_SNAPSHOT
trace_create_cpu_file("snapshot", 0644, d_cpu,
@ -6156,7 +6131,7 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
tr, &tracing_pipe_fops);
trace_create_file("buffer_size_kb", 0644, d_tracer,
(void *)&tr->trace_cpu, &tracing_entries_fops);
tr, &tracing_entries_fops);
trace_create_file("buffer_total_size_kb", 0444, d_tracer,
tr, &tracing_total_entries_fops);