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Subject: Re: perf/jit doesn't cope well with mprotect() to jit containing pages
From: Andres Freund <andres@anarazel.de>
Date: Mon, 12 Dec 2016 01:01:48 -0800
To: Peter Zijlstra <peterz@infradead.org>
CC: linux-kernel@vger.kernel.org, Stephane Eranian <eranian@google.com>,
        acme@kernel.org, jolsa@redhat.com, mingo@elte.hu, anton@ozlabs.org,
        namhyung@kernel.org, Stephane Eranian <eranian@gmail.com>
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On December 12, 2016 12:49:03 AM PST, Peter Zijlstra <peterz@infradead.org> wrote:
>On Fri, Dec 09, 2016 at 09:02:18PM -0800, Andres Freund wrote:

>> Am I doing something wrong, or is there a bug here?
>
>Expected behaviour afaict

So I need to prevent vma  merging to use perf jit support? That seems a bit weird.  Possibly the inject --jit  pass needs to do something about this? A hack might be to re-emit  the fake mmap2 records after ones potentially overwriting previously emitted records.   Don't know perf internals well enough to suggest something prettier.

Andres
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