Re: [PATCH] ftrace: fix current_tracer error return

From: Frédéric Weisbecker
Date: Tue Oct 28 2008 - 11:35:28 EST


2008/10/28 Steven Rostedt <rostedt@xxxxxxxxxxx>:
>
> The commit (in linux-tip) c2931e05ec5965597cbfb79ad332d4a29aeceb23
> ( ftrace: return an error when setting a nonexistent tracer )
> added useful code that would error when a bad tracer was written into
> the current_tracer file.
>
> But this had a bug if the amount written was more than the amount read by
> that code. The first iteration would set the tracer correctly, but since
> it did not consume the rest of what was written (usually whitespace), the
> userspace utility would continue to write what was not consumed. This
> second iteration would fail to find a tracer and return -EINVAL. Funny
> thing is that the tracer would have already been set.
>
> This patch just consumes all the data that is written to the file.
>
>
> Signed-off-by: Steven Rostedt <srostedt@xxxxxxxxxx>



An that corrects the bug when I failed to assign the sched_switch tracer.
Thanks Steven!

Tested-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
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