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SubjectRe: [PATCH v2] tracing: fix referencing after memory freeing and refactors code
On Wed,  6 Nov 2013 16:02:51 -0300
"Geyslan G. Bem" <geyslan@gmail.com> wrote:

> In 'system_tr_open()':
> Fix possible 'dir' assignment after freeing it.

I'll take this patch, but I'm going to reword the subject and the
change log. The assignment of dir to filp->private_data after dir is
freed is not as bad as it sounds. As we are returning an error,
filp->private_data is never used.

-- Steve


>
> In both functions:
> Restructures logic conditions testing 'tracing_is_disabled()'
> return before the others tests.
>
> Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
> ---
> 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 368a4d5..b44a7ea 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)



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