From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 40FFF6B0071 for ; Wed, 9 Jun 2010 21:16:44 -0400 (EDT) Date: Wed, 9 Jun 2010 21:16:17 -0400 From: Rik van Riel Subject: [PATCH -mm] only drop root anon_vma if not self Message-ID: <20100609211617.3e7e41bd@annuminas.surriel.com> In-Reply-To: References: <1275929000.3021.56.camel@e102109-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Dave Young Cc: Catalin Marinas , Andrew Morton , Linux Kernel Mailing List , linux-mm@kvack.org List-ID: On Wed, 9 Jun 2010 17:19:02 +0800 Dave Young wrote: > > Manually bisected mm patches, the memleak caused by following patch: > > > > mm-extend-ksm-refcounts-to-the-anon_vma-root.patch > > > So I guess the refcount break, either drop-without-get or over-drop I'm guessing I did not run the kernel with enough debug options enabled when I tested my patches... Dave & Catalin, thank you for tracking this down. Dave, does the below patch fix your issue? Andrew, if the patch below works, you'll probably want to merge it as mm-extend-ksm-refcounts-to-the-anon_vma-root-fix.patch :) ---------------- With the new anon_vma code we take a refcount on the root anon_vma. However, the root anon_vma does not have a refcount on itself, so we should not try to do a drop on itself when it is being unlinked. Signed-off-by: Rik van Riel --- linux-2.6-rtavma/mm/rmap.c.orig 2010-06-09 21:10:07.349376896 -0400 +++ linux-2.6-rtavma/mm/rmap.c 2010-06-09 21:10:24.180406299 -0400 @@ -275,7 +275,8 @@ static void anon_vma_unlink(struct anon_ if (empty) { /* We no longer need the root anon_vma */ - drop_anon_vma(anon_vma->root); + if (anon_vma->root != anon_vma) + drop_anon_vma(anon_vma->root); anon_vma_free(anon_vma); } } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org