From: Andi Kleen <ak@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: Andi Kleen <ak@suse.de>,
davem@davemloft.net, dwmw2@infradead.org,
linux-arch@vger.kernel.org
Subject: Re: TASK_SIZE is variable.
Date: Wed, 26 Jan 2005 08:43:06 +0100 [thread overview]
Message-ID: <20050126074306.GE7198@wotan.suse.de> (raw)
In-Reply-To: <20050125232441.6efb49c1.akpm@osdl.org>
On Tue, Jan 25, 2005 at 11:24:41PM -0800, Andrew Morton wrote:
> Andi Kleen <ak@suse.de> wrote:
> >
> > After rereading Anton's post on l-k I think the problem happens
> > when a proc accesses (like read on /proc/*/cmdline) increases the
> > reference count of a mm, then the mm exits, and then the other
> > process reading /proc does the final mmput. Then the exit_mmap
> > executes in the context of the other process.
>
> yup. This happens in quite a few places. Everything under mmput() needs
> to understand that the mm isn't necessarily current's mm. I'm not sure
> that introcuction of additional locking to prevent that would be very nice.
After thinking about it more I agree. Just replacing TASK_SIZE with
something that depends on the mm is the best solution here.
> (Could we null out current->mm during mmput() to catch buggy code, or would
> that break the lazy-tlb code?)
It wouldn't have caught TASK_SIZE anyways, I'm not sure how useful this is.
-Andi
next prev parent reply other threads:[~2005-01-26 7:43 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-25 22:26 TASK_SIZE is variable David Woodhouse
2005-01-25 23:52 ` David S. Miller
2005-01-26 6:36 ` Andi Kleen
2005-01-26 6:41 ` David S. Miller
2005-01-26 7:13 ` Andi Kleen
2005-01-26 7:24 ` Andrew Morton
2005-01-26 7:43 ` Andi Kleen [this message]
2005-01-26 8:01 ` Andrew Morton
2005-01-26 8:04 ` Andi Kleen
2005-01-28 2:58 ` Paul Mackerras
2005-01-28 3:11 ` Paul Mackerras
2005-01-28 3:17 ` Andrew Morton
2005-01-28 6:40 ` Andi Kleen
2005-01-29 11:23 ` Anton Blanchard
2005-01-28 8:46 ` Russell King
2005-01-28 6:39 ` Andi Kleen
2005-01-28 11:32 ` David Woodhouse
2005-01-26 7:54 ` David Woodhouse
2005-01-29 20:23 ` Andrew Morton
2005-01-29 23:28 ` Paul Mackerras
2005-01-30 11:01 ` Andi Kleen
2005-01-30 12:10 ` Paul Mackerras
2005-01-31 2:23 ` David S. Miller
2005-01-31 9:23 ` Andi Kleen
2005-01-31 19:29 ` David S. Miller
2005-01-31 19:38 ` Andi Kleen
2005-01-31 20:35 ` David S. Miller
2005-02-03 4:08 ` Andrew Morton
2005-02-03 6:28 ` David S. Miller
2005-02-03 7:19 ` Andi Kleen
2005-02-03 9:23 ` David Woodhouse
2005-01-31 2:33 ` Matthew Wilcox
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