From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1CF74C43441 for ; Fri, 23 Nov 2018 11:16:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC6C220659 for ; Fri, 23 Nov 2018 11:16:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC6C220659 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394326AbeKWV7t (ORCPT ); Fri, 23 Nov 2018 16:59:49 -0500 Received: from mx2.suse.de ([195.135.220.15]:53388 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387941AbeKWV7t (ORCPT ); Fri, 23 Nov 2018 16:59:49 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 9B019AEA1; Fri, 23 Nov 2018 11:15:57 +0000 (UTC) Date: Fri, 23 Nov 2018 12:15:57 +0100 From: Michal Hocko To: Daniel Vetter Cc: LKML , Linux MM , Intel Graphics Development , DRI Development , Andrew Morton , Christian =?iso-8859-1?Q?K=F6nig?= , David Rientjes , =?iso-8859-1?B?Suly9G1l?= Glisse , Paolo Bonzini , Daniel Vetter Subject: Re: [PATCH 1/3] mm: Check if mmu notifier callbacks are allowed to fail Message-ID: <20181123111557.GG8625@dhcp22.suse.cz> References: <20181122165106.18238-1-daniel.vetter@ffwll.ch> <20181122165106.18238-2-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20181122165106.18238-2-daniel.vetter@ffwll.ch> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 22-11-18 17:51:04, Daniel Vetter wrote: > Just a bit of paranoia, since if we start pushing this deep into > callchains it's hard to spot all places where an mmu notifier > implementation might fail when it's not allowed to. What does WARN give you more than the existing pr_info? Is really backtrace that interesting? > Cc: Andrew Morton > Cc: Michal Hocko > Cc: "Christian König" > Cc: David Rientjes > Cc: Daniel Vetter > Cc: "Jérôme Glisse" > Cc: linux-mm@kvack.org > Cc: Paolo Bonzini > Signed-off-by: Daniel Vetter > --- > mm/mmu_notifier.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c > index 5119ff846769..59e102589a25 100644 > --- a/mm/mmu_notifier.c > +++ b/mm/mmu_notifier.c > @@ -190,6 +190,8 @@ int __mmu_notifier_invalidate_range_start(struct mm_struct *mm, > pr_info("%pS callback failed with %d in %sblockable context.\n", > mn->ops->invalidate_range_start, _ret, > !blockable ? "non-" : ""); > + WARN(blockable,"%pS callback failure not allowed\n", > + mn->ops->invalidate_range_start); > ret = _ret; > } > } > -- > 2.19.1 > -- Michal Hocko SUSE Labs