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Date: Tue, 23 Jul 2013 17:26:06 +0200
From: Oleg Nesterov <oleg@...hat.com>
To: Al Viro <viro@...iv.linux.org.uk>,
Steven Rostedt <rostedt@...dmis.org>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Alexander Z Lam <azl@...gle.com>, David Sharp <dhsharp@...gle.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...hat.com>,
Vaibhav Nagarnaik <vnagarnaik@...gle.com>,
"zhangwei(Jovi)" <jovi.zhangwei@...wei.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH v2 5/7] tracing: Change tracing_entries_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 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().
Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
kernel/trace/trace.c | 49 ++++++++++++-------------------------------------
1 files changed, 12 insertions(+), 37 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e29dc8f..68b4685 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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);
--
1.5.5.1
--
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