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To: "Manfred Spraul" <manfred@colorfullife.com>
Cc: <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Longstanding elf fix (2.4.3 fix)
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From: ebiederm@xmission.com (Eric W. Biederman)
Date: 24 Apr 2001 01:19:28 -0600
In-Reply-To: "Manfred Spraul"'s message of "Mon, 23 Apr 2001 23:54:22 +0200"
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"Manfred Spraul" <manfred@colorfullife.com> writes:

> > Well looking a little more closely than I did last night it looks like
> > access_process_vm (called from ptrace) can cause what amounts to a
> > page fault at pretty arbitrary times.
> 
> It's also used for several /proc/<pid> files.
> 
> I remember that I got crashes with concurrent exec+cat
> /proc/<pid>/cmdline until down(mmap_sem) was added into
> setup_arg_pages().

O.k. Then the race I'm catching is real though because it is confined
to bss sections, we are quite unlikely to trigger it.

Eric