From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932266Ab1IMSSH (ORCPT ); Tue, 13 Sep 2011 14:18:07 -0400 Received: from gate.crashing.org ([63.228.1.57]:33925 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932101Ab1IMSSC (ORCPT ); Tue, 13 Sep 2011 14:18:02 -0400 Subject: Re: [PATCH 0/2] PCI: PCI-E MPS bug fixes From: Benjamin Herrenschmidt To: Jon Mason Cc: Linus Torvalds , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Jesse Barnes In-Reply-To: <1315911045.455.150.camel@pasglop> References: <1315518078-30619-1-git-send-email-mason@myri.com> <6dad18a7-cf65-46db-8283-78b8da5bfa3a@email.android.com> <1315911045.455.150.camel@pasglop> Content-Type: text/plain; charset="UTF-8" Date: Tue, 13 Sep 2011 15:17:32 -0300 Message-ID: <1315937852.455.156.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-09-13 at 07:50 -0300, Benjamin Herrenschmidt wrote: > > > > You should apply them. I would queue them, and but I don't have > > another PCI tree anywhere for you to pull them. > > > > In fact, I'll be out for the next few weeks; I'll ask Bjorn to cover > > for me. > > Note that I might be missing some patches, but what's currently in Linus > tree is rather wrong. > > The comment is right, but the implementation is bogus: Oh and another one (again, I never saw the patches I'm responding to for some odd reason, only email 0/2, so you might have already fixed that): When using "safe" mode, I get a crash in pcie_find_smpss(). Patch below. >>From 1b542d690323fab332e61099193d598c5c515d13 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Tue, 13 Sep 2011 15:16:33 -0300 Subject: [PATCH] pci: Don't crash when reading mpss from root complex In pcie_find_smpss(), we have the following statement: if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) || dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT)) The problem is that at least on my machine, this gets called for the root complex (virtual P2P bridge), and dev->bus->self is NULL since the parent bus for this is not itself anchor to a PCI device. This adds the necessary NULL check. Signed-off-by: Benjamin Herrenschmidt --- drivers/pci/probe.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8473727..09d1c0f 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1351,7 +1351,8 @@ static int pcie_find_smpss(struct pci_dev *dev, void *data) * will occur as normal. */ if (dev->is_hotplug_bridge && (!list_is_singular(&dev->bus->devices) || - dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT)) + (dev->bus->self && + dev->bus->self->pcie_type != PCI_EXP_TYPE_ROOT_PORT))) *smpss = 0; if (*smpss > dev->pcie_mpss) -- 1.7.4.1