From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762027Ab0J2U7U (ORCPT ); Fri, 29 Oct 2010 16:59:20 -0400 Received: from mail-ew0-f46.google.com ([209.85.215.46]:58776 "EHLO mail-ew0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758342Ab0J2U7T (ORCPT ); Fri, 29 Oct 2010 16:59:19 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; b=dpwOFAczwT9STe3acoBwbmEpp1L5xLQFmc4sxoTXDyga/cx/grMkm5rwa9X4a9xkD0 hg2zmf9YTIDld5OdJkZCRwLJ02NVHUkpxKfKZ/6oImRlGsPiEPeqSqytVM/C24kaptN3 NyNYec67JvQ73i8LQj2eLhv22FhrtBAQRliow= Date: Sat, 30 Oct 2010 00:59:15 +0400 From: Cyrill Gorcunov To: Eric Dumazet Cc: Peter Zijlstra , mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, brgerst@gmail.com, tglx@linutronix.de, mingo@elte.hu, linux-tip-commits@vger.kernel.org Subject: Re: [tip:x86/urgent] x86-32: Restore irq stacks NUMA-aware allocations Message-ID: <20101029205915.GC6130@lenovo> References: <1288276854.2649.607.camel@edumazet-laptop> <1288377146.1988.0.camel@laptop> <20101029202809.GB6130@lenovo> <1288385587.2680.13.camel@edumazet-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1288385587.2680.13.camel@edumazet-laptop> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 29, 2010 at 10:53:07PM +0200, Eric Dumazet wrote: > Le samedi 30 octobre 2010 à 00:28 +0400, Cyrill Gorcunov a écrit : > > On Fri, Oct 29, 2010 at 08:32:26PM +0200, Peter Zijlstra wrote: > > > On Fri, 2010-10-29 at 06:43 +0000, tip-bot for Eric Dumazet wrote: > > > > + irqctx = page_address(alloc_pages_node(cpu_to_node(cpu), > > > > + THREAD_FLAGS, > > > > + THREAD_ORDER)); > > > > > > Shouldn't we be checking for a NULL return from alloc_pages_node() > > > before calling page_address() on it? > > > -- > > > > I didnt check for NULL because original code was not either. > > If you cannot allocate memory for the IRQ stack, only choice is to crash > anyway. > > Adding BUG_ON() is not that helpful in this respect. > I believe it was a nit in first place, so the BUG_ON simply tells to code readers that we knew the NULL can happen here but there is simply no way to continue then. Cyrill