From: ebiederman@lnxi.com (Eric W. Biederman)
To: "David S. Miller" <davem@redhat.com>
Cc: Linus Torvalds <torvalds@transmeta.com>,
<linux-kernel@vger.kernel.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH] Longstanding elf fix (2.4.3 fix)
Date: 23 Apr 2001 01:44:57 -0600 [thread overview]
Message-ID: <m3snj0giva.fsf@DLT.linuxnetworx.com> (raw)
In-Reply-To: <m31yqk8oas.fsf@DLT.linuxnetworx.com> <15075.40500.408470.152332@pizda.ninka.net>
In-Reply-To: "David S. Miller"'s message of "Sun, 22 Apr 2001 20:15:00 -0700 (PDT)"
"David S. Miller" <davem@redhat.com> writes:
> Eric W. Biederman writes:
> > In building a patch for 2.4.3 I also discovered that we are not taking
> > the mmap_sem around do_brk in the exec paths.
>
> Does that really matter?
In the library loader I can certainly see it making a difference.
> Who else can get at the address space?
> We are a singly referenced address space at that point... perhaps ptrace?
In practice I don't see it being a big deal. But reliable code is
made by closing all of the little loop holes.
It also improves consistency as all of the calls to do_mmap are
already protected in the exec paths.
And of course since much of the code in the kernel is built on the
copy a good example neglecting the locking without a big comment,
invites trouble elsewhere like in elf_load_library. Where we could
have multiple threads running.
Eric
next prev parent reply other threads:[~2001-04-23 7:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-04-23 0:14 [PATCH] Longstanding elf fix (2.4.3 fix) Eric W. Biederman
2001-04-23 3:15 ` David S. Miller
2001-04-23 7:44 ` Eric W. Biederman [this message]
2001-04-23 7:59 ` Philip Blundell
2001-04-23 16:05 ` Eric W. Biederman
2001-04-23 17:39 ` Linus Torvalds
2001-04-23 18:54 ` Eric W. Biederman
2001-04-24 22:34 ` Ion Badulescu
2001-04-24 23:34 ` Eric W. Biederman
-- strict thread matches above, loose matches on Subject: below --
2001-04-23 21:54 Manfred Spraul
2001-04-24 7:19 ` Eric W. Biederman
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