Re: [PATCH 1/1] tracing: Simplify trace_array_get()

From: Oleg Nesterov
Date: Fri Jul 19 2013 - 12:38:19 EST


On 07/19, Steven Rostedt wrote:
>
> On Fri, 2013-07-19 at 17:51 +0200, Oleg Nesterov wrote:
> > mutex_lock(&trace_types_lock);
> > - list_for_each_entry(tr, &ftrace_trace_arrays, list) {
> > - if (tr == this_tr) {
> > - tr->ref++;
> > - ret = 0;
> > - break;
> > - }
> > + if (!list_empty(&this_tr->list)) {
>
> Because this_tr can be freed outside the lock. Accessing this_tr->list
> can cause a crash.

Aaah, indeed.

Thanks Steven!

Oleg.

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