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From: Matt Mackall <mpm@selenic.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@sw.ru>,
	linux-kernel@vger.kernel.org,
	Nick Piggin <nickpiggin@yahoo.com.au>
Subject: Re: - maps2-add-proc-pid-pagemap-interface-fix.patch removed from -mm tree
Date: Fri, 27 Apr 2007 15:41:55 -0500	[thread overview]
Message-ID: <20070427204155.GT11115@waste.org> (raw)
In-Reply-To: <20070427132713.fc9d82c0.akpm@linux-foundation.org>

On Fri, Apr 27, 2007 at 01:27:13PM -0700, Andrew Morton wrote:
> On Fri, 27 Apr 2007 14:45:33 +0400
> Alexey Dobriyan <adobriyan@sw.ru> wrote:
> 
> > > maps2-add-proc-pid-pagemap-interface.patch
> > 
> > Ohhh, you're repeating december mincore() bug
> > 2f77d107050abc14bc393b34bdb7b91cf670c250
> > 
> > pagemap_read() takes ->mmap_sem for reading
> > walk_page_range
> > pagemap_pte_range
> > add_to_pagemap
> > flush_pagemap
> > copy_to_user
> 
> argh.  I think it's always a bug to run uaccess functions while holding
> mmap_sem, isn't it?

Yep, looks that way.

> I'll see if I can get something like this working as a -mm-only thing:

I was wondering if there was a sensible way to do this. This looks
pretty good.
 
> +	no+_mmap_sem();						\

Except for this bit. Maybe put it in the same config bucket as might_sleep?

-- 
Mathematics is the supreme nostalgia of our time.

  reply	other threads:[~2007-04-27 20:55 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <200704270814.l3R8EnFJ023047@shell0.pdx.osdl.net>
2007-04-27 10:45 ` Alexey Dobriyan
2007-04-27 20:27   ` Andrew Morton
2007-04-27 20:41     ` Matt Mackall [this message]
2007-04-27 21:31       ` Andrew Morton
2007-04-28  5:13         ` Hugh Dickins
2007-04-28  5:48           ` Andrew Morton

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