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Date:   Wed, 29 Sep 2021 10:48:53 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     Kees Cook <keescook@chromium.org>,
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Subject: Re: [PATCH] proc: Disable /proc/$pid/wchan
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On Fri, Sep 24, 2021 at 02:54:24PM +0100, Mark Rutland wrote:
> We could instead have the scheduler entrypoints snapshot their caller
> into a field in task_struct. If there are sufficiently few callers, that
> could be an inline wrapper that passes a __func__ string. Otherwise, we
> still need to symbolize.

I strongly dislike that option, we'd make the scheduler slower for
something that's typically unused.

The 3 people actually using wchan should pay the cost of obtaining the
data, not everybody all the time.