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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 24 Nov 2023 12:12:20 -0800
Message-ID: <CAHk-=wjCS30Mqy9b=op2f=ir9iPQfQ2Efjo1b8yMeJrXcWTtWA@mail.gmail.com>
Subject: Re: [GIT PULL] vfs fixes
To:     Christian Brauner <brauner@kernel.org>,
        Omar Sandoval <osandov@fb.com>,
        David Howells <dhowells@redhat.com>
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
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On Fri, 24 Nov 2023 at 10:52, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Gaah. I guess it's the VM_IOREMAP case that is the cause of all this horridness.
>
> So we'd have to know not to mess with IO mappings. Annoying.

Doing a debian code search, I see a number of programs that do a
"stat()" on the kcore file, to get some notion of "system memory
size". I don't think it's valid, but whatever. We probably shouldn't
change it.

I also see some programs that actually read the ELF notes and sections
for dumping purposes.

But does anybody actually run gdb on that thing or similar? That's the
original model for that file, but it was always more of a gimmick than
anything else.

Because we could just say "read zeroes from KCORE_VMALLOC" and be done
with it that way.

                  Linus