From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752168AbbIQV0r (ORCPT ); Thu, 17 Sep 2015 17:26:47 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:50874 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751260AbbIQV0p (ORCPT ); Thu, 17 Sep 2015 17:26:45 -0400 Date: Thu, 17 Sep 2015 14:26:44 -0700 From: Andrew Morton To: Sowmini Varadhan Cc: linux-kernel@vger.kernel.org, benh@kernel.crashing.org, linux@roeck-us.net, davem@davemloft.net Subject: Re: [PATCH] iommu-common: Do not try to deref a null iommu->lazy_flush() pointer when n < pool->hint Message-Id: <20150917142644.a7a3c272be10280028c5ad3a@linux-foundation.org> In-Reply-To: <20150917015043.GC13020@oracle.com> References: <20150917015043.GC13020@oracle.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 16 Sep 2015 21:50:43 -0400 Sowmini Varadhan wrote: > The check for invoking iommu->lazy_flush() from iommu_tbl_range_alloc() > has to be refactored so that we only call ->lazy_flush() if it is non-null. Patch looks good. But I don't know which kernel versions need the fix. So, when fixing a bug please always describe the end-user visible effects of that bug. Under what circumstances did your kernel crash?