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Date: Wed, 16 Sep 2026 17:30:53 -0700
From: Namhyung Kim <namhyung@kernel.org>
To: Alireza Haghdoost <haghdoost@uber.com>
Cc: sashiko-reviews@lists.linux.dev, linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 1/4] perf symbols: Fix broken ELF_C_READ_MMAP fallback
 guard
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In-Reply-To: <CA+w=M=Rpvn9QpbvC4UWex91wNZ39BNmjt2-PaACNS1Rsai3uGg@mail.gmail.com>

Hello,

On Tue, Sep 15, 2026 at 12:04:27PM -0700, Alireza Haghdoost wrote:
> > Could we restore a proper feature detection mechanism here rather than
> > relying on an unconditional definition?
> 
> Thanks, this is a valid concern. I’ll restore the compile-time
> feature-libelf-mmap probe removed by 22dd1ac91a77 and use it to select
> between ELF_C_READ_MMAP and ELF_C_READ in v2.

Please don't.

I think we already require much recent versions of elfutils like 0.157
for libdw which is released more than 10 years ago.  So I think it's ok
just to assume _MMAP is available.

Thanks,
Namhyung