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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Marcelo Tosatti <marcelo.tosatti@cyclades.com>,
	Andrew Morton <akpm@osdl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] do_brk() needs mmap_sem write-locked
Date: Thu, 13 Jan 2005 15:36:21 +0000	[thread overview]
Message-ID: <1105626859.4624.18.camel@localhost.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.58.0501120800500.2373@ppc970.osdl.org>

On Mer, 2005-01-12 at 16:03, Linus Torvalds wrote:
> if that warning ever triggers, mmap_sem will now be locked, and that will 
> cause problems. So I suspect it's better to do
> 
> 	if (down_read_trylock(&mm->mmap_sem)) {
> 		WARN_ON(1);
> 		up_read(&mm->mmap_sem);

Better to leave the lock held and remember the error then drop it at the
end - anything else means the WARN_ON case is a security hole.


      parent reply	other threads:[~2005-01-13 16:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-12  0:21 [PATCH] do_brk() needs mmap_sem write-locked Marcelo Tosatti
2005-01-12 16:03 ` Linus Torvalds
2005-01-12 15:27   ` Marcelo Tosatti
2005-01-13 15:36   ` Alan Cox [this message]

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