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Date:   Sat, 25 Nov 2023 14:10:52 +0100
From:   Christian Brauner <brauner@kernel.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Omar Sandoval <osandov@fb.com>,
        David Howells <dhowells@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [GIT PULL] vfs fixes
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References: <20231124-vfs-fixes-3420a81c0abe@brauner>
 <CAHk-=wiJFsu70BqrgxtoAfMHeJVJMfsWzQ42PXFduGNhFSVGDA@mail.gmail.com>
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On Fri, Nov 24, 2023 at 10:25:15AM -0800, Linus Torvalds wrote:
> On Fri, 24 Nov 2023 at 02:28, Christian Brauner <brauner@kernel.org> wrote:
> >
> > * Fix a bug introduced with the iov_iter rework from last cycle.
> >
> >   This broke /proc/kcore by copying too much and without the correct
> >   offset.
> 
> Ugh. I think the whole /proc/kcore vmalloc handling is just COMPLETELY broken.

Ugh, I didn't even look at that closely because the fix was obviously
correct for that helper alone. Let's try and just return zeroed memory
like you suggested in your last mail before we bother fixing any of
this.

Long-term plan, it'd be nice to just get distros to start turning
/proc/kcore off. Maybe I underestimate legitimate users but this
requires CAP_SYS_RAW_IO so it really can only be useful to pretty
privileged stuff anyway.