From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751660AbdITFv2 (ORCPT ); Wed, 20 Sep 2017 01:51:28 -0400 Received: from LGEAMRELO12.lge.com ([156.147.23.52]:44105 "EHLO lgeamrelo12.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751480AbdITFv1 (ORCPT ); Wed, 20 Sep 2017 01:51:27 -0400 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.220.163 X-Original-MAILFROM: minchan@kernel.org Date: Wed, 20 Sep 2017 14:51:25 +0900 From: Minchan Kim To: Sergey Senozhatsky Cc: Andrew Morton , linux-kernel@vger.kernel.org, kernel-team , Sergey Senozhatsky Subject: Re: [PATCH] zram: fix null dereference of handle Message-ID: <20170920055125.GB9428@bbox> References: <20170919102125.GB401@jagdpanzerIV.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170919102125.GB401@jagdpanzerIV.localdomain> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 19, 2017 at 07:21:25PM +0900, Sergey Senozhatsky wrote: > Minchan, > > I just ran across it [because I had a bug to analize where this > part was involved]. I'd really prefer the kernel to BUG_ON immediately > instead of dying in agony. > > can we, please, return BUG_ON() back? > > there is no point in trying to save the kernel once it did that type > of violation. I agree. If it happens, it would corrupt other user's buffer which ends up leaking some private data from others so there is pointless to keep system alive to debug it. Do you mind sending a formal patch? Thanks! > > --- > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index 7c38e850a8fc..685049a9048d 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -1349,7 +1349,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle, > * pools/users, we can't allow mapping in interrupt context > * because it can corrupt another users mappings. > */ > - WARN_ON_ONCE(in_interrupt()); > + BUG_ON(in_interrupt()); > > /* From now on, migration cannot move the object */ > pin_tag(handle); >