From d6d3523caab75196560c85aae80cb8f4a8e380ea Mon Sep 17 00:00:00 2001 From: "Geyslan G. Bem" Date: Wed, 6 Nov 2013 16:02:51 -0300 Subject: [PATCH] tracing: Do not assign filp->private_data to freed memory 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 Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 043f833246a0..f919a2e21bf3 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -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) -- 2.34.1