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From: William Lee Irwin III <wli@holomorphy.com>
To: Andi Kleen <ak@muc.de>
Cc: Anton Blanchard <anton@samba.org>,
	linux-kernel@vger.kernel.org, spyro@f2s.com
Subject: Re: [PATCH] Use MM_VM_SIZE in exit_mmap
Date: Tue, 25 Jan 2005 23:39:48 -0800	[thread overview]
Message-ID: <20050126073948.GJ10843@holomorphy.com> (raw)
In-Reply-To: <m1zmyw4rlj.fsf@muc.de>

Anton Blanchard <anton@samba.org> writes:
>> It is possible for one task to end up "owning" an mm from another - we
>> have seen this with the procfs code when process 1 accesses
>> /proc/pid/cmdline of process 2 while it is exiting.  Process 2 exits
>> but does not tear its mm down. Later on process 1 finishes with the proc
>> file and the mm gets torn down at this point.

On Wed, Jan 26, 2005 at 07:44:24AM +0100, Andi Kleen wrote:
> IMHO that's the root bug. That sounds really dangerous and will likely
> cause other problems because it is totally unexpected. How about fixing
> /proc to not do this?

It would not be meaningful. It's a natural outcome of reference
counting the mm, /proc/ is far from the only place that acquires
references on mm's, and they're all necessary.


-- wli

      reply	other threads:[~2005-01-26  7:40 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-25 14:22 [PATCH] Use MM_VM_SIZE in exit_mmap Anton Blanchard
2005-01-25 16:46 ` Chris Wedgwood
2005-01-25 16:57   ` Anton Blanchard
2005-01-25 17:13     ` Chris Wedgwood
2005-01-27 20:46     ` [PATCH RFC] Change (some) TASK_SIZE to task_vtop(current) Chris Wedgwood
2005-01-25 23:02 ` [PATCH] Use MM_VM_SIZE in exit_mmap Ian Molton
2005-01-25 23:39   ` Russell King
2005-01-26  0:01     ` Anton Blanchard
2005-01-26  0:17 ` Nick Piggin
2005-01-26  6:44 ` Andi Kleen
2005-01-26  7:39   ` William Lee Irwin III [this message]

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