From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id 10A305F0001 for ; Tue, 7 Apr 2009 16:22:16 -0400 (EDT) Date: Tue, 7 Apr 2009 22:24:49 +0200 From: Andi Kleen Subject: Re: [PATCH] [8/16] POISON: Add various poison checks in mm/memory.c Message-ID: <20090407202449.GX17934@one.firstfloor.org> References: <20090407509.382219156@firstfloor.org> <20090407151005.4E24B1D046D@basil.firstfloor.org> <20090407190330.GB3818@cmpxchg.org> <20090407193145.GU17934@one.firstfloor.org> <20090407201708.GA4220@cmpxchg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090407201708.GA4220@cmpxchg.org> Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: Andi Kleen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org List-ID: > I think we missed each other here. I wasn't talking about _why_ you > take that reference -- that is clear. But I see these two > possibilities: > > a) memory_failure() is called on a page on the free list, the > get_page() will trigger a bug because the refcount is 0 Ah got it now. Sorry for misreading you. That's indeed a problem. Fixing. free pages was something my injector based test suite didn't cover :/ > b) if that is not possible, the above check is not needed There was at least one case where the process could free it anyways. I think. Or maybe that was something I fixed in a different way. It's possible this check is not needed, but it's probably safer to keep it (and it's all super slow path) -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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