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tracing: Do not assign filp->private_data to freed memory

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In system_tr_open(), the filp->private_data can be assigned the 'dir'
variable even if it was freed. This is on the error path, and is
harmless because the error return code will prevent filp->private_data
from being used. But for correctness, we should not assign it to
a recently freed variable, as that can cause static tools to give
false warnings.

Also have both subsystem_open() and system_tr_open() return -ENODEV
if tracing has been disabled.

Link: http://lkml.kernel.org/r/1383764571-7318-1-git-send-email-geyslan@gmail.com

Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Geyslan G. Bem 2013-11-06 16:02:51 -03:00 committed by Steven Rostedt
parent 2e86421deb
commit d6d3523caa
1 changed files with 8 additions and 1 deletions
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9
kernel/trace/trace_events.c
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@ -1062,6 +1062,9 @@ static int subsystem_open(struct inode *inode, struct file *filp)
struct trace_array *tr;
int ret;
if (tracing_is_disabled())
return -ENODEV;
/* Make sure the system still exists */
mutex_lock(&trace_types_lock);
mutex_lock(&event_mutex);
@ -1108,6 +1111,9 @@ static int system_tr_open(struct inode *inode, struct file *filp)
struct trace_array *tr = inode->i_private;
int ret;
if (tracing_is_disabled())
return -ENODEV;
if (trace_array_get(tr) < 0)
return -ENODEV;
@ -1124,11 +1130,12 @@ static int system_tr_open(struct inode *inode, struct file *filp)
if (ret < 0) {
trace_array_put(tr);
kfree(dir);
return ret;
}
filp->private_data = dir;
return ret;
return 0;
}
static int subsystem_release(struct inode *inode, struct file *file)