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From: Daniel Phillips <phillips@arcor.de>
To: Marcelo Tosatti <marcelo@conectiva.com.br>, linux-kernel@vger.kernel.org
Subject: Race in shrink_cache
Date: Thu, 5 Sep 2002 07:04:28 +0200	[thread overview]
Message-ID: <E17mooe-00064m-00@starship> (raw)

Hi Marcelo,

This looks really suspicious, vmscan.c#435:

	spin_unlock(&pagemap_lru_lock);
							if (put_page_testzero(page))
								__free_pages_ok(page, 0);
	/* avoid to free a locked page */
	page_cache_get(page);

	/* whoops, double free coming */

I suggest you bump the page count before releasing the lru lock.  The race
shown above may not in fact be possible, but the current code is fragile.

-- 
Daniel

             reply	other threads:[~2002-09-05  4:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-09-05  5:04 Daniel Phillips [this message]
2002-09-05  6:36 ` Andrew Morton
2002-09-05  6:36   ` Daniel Phillips
2002-09-05  7:07     ` Andrew Morton
2002-09-05  7:28       ` Daniel Phillips
2002-09-05  7:53         ` Andrew Morton
2002-09-05 18:41           ` Daniel Phillips
2002-09-05 18:51             ` Andrew Morton
2002-09-05 19:08               ` Daniel Phillips
2002-09-05 19:22                 ` Andrew Morton
2002-09-05 20:00                   ` Daniel Phillips
2002-09-05 13:33     ` Rik van Riel

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