From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757139Ab0GWBTz (ORCPT ); Thu, 22 Jul 2010 21:19:55 -0400 Received: from mail.solarflare.com ([216.237.3.220]:4862 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756929Ab0GWBTx (ORCPT ); Thu, 22 Jul 2010 21:19:53 -0400 Subject: Re: linux-next: OOPS at bot time From: Ben Hutchings To: Stephen Rothwell Cc: ppc-dev , LKML , Jesse Barnes In-Reply-To: <20100723102202.871a3131.sfr@canb.auug.org.au> References: <20100723102202.871a3131.sfr@canb.auug.org.au> Content-Type: text/plain; charset="UTF-8" Organization: Solarflare Communications Date: Fri, 23 Jul 2010 02:19:45 +0100 Message-ID: <1279847985.4883.391.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.30.2 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 23 Jul 2010 01:21:29.0602 (UTC) FILETIME=[60B74E20:01CB2A05] X-TM-AS-Product-Ver: SMEX-8.0.0.1181-6.000.1038-17520.005 X-TM-AS-Result: No--22.808200-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2010-07-23 at 10:22 +1000, Stephen Rothwell wrote: > Hi all, > > My Power7 boot test paniced like this: (next-20100722) > > %GQLogic Fibre Channel HBA Driver: 8.03.03-k0 > qla2xxx 0002:01:00.2: enabling device (0144 -> 0146) > qla2xxx 0002:01:00.2: Found an ISP8001, irq 35, iobase 0xd000080080014000 > ------------[ cut here ]------------ > kernel BUG at drivers/pci/msi.c:205! [...] > Call Trace: > [c00000000278b270] [c000000000048d9c] .rtas_setup_msi_irqs+0x1d8/0x254 (unreliable) > [c00000000278b360] [c00000000002a9cc] .arch_setup_msi_irqs+0x34/0x4c > [c00000000278b3e0] [c0000000002fd3fc] .pci_enable_msix+0x49c/0x4ac [...] > That line number is this: > > BUG_ON(!(entry->msg.address_hi | entry->msg.address_lo | > entry->msg.data)); > > in read_msi_msg_desc(). That BUG_ON was added by commit > 2ca1af9aa3285c6a5f103ed31ad09f7399fc65d7 ("PCI: MSI: Remove unsafe and > unnecessary hardware access") from the pci tree. I wanted to assert that read_msi_msg_desc() is only used to update MSI/MSI-X descriptors that have already been generated by Linux. It looks like you found an exception. We could make read_msi_msg() fall back to reading from the hardware, but I think that what the pSeries code is trying to do - save an MSI message generated by firmware - is different from what the other callers want. Instead we could add: void save_msi_msg(unsigned int irq) { struct irq_desc *desc = irq_to_desc(irq); struct msi_desc *entry = get_irq_desc_msi(desc); struct msi_msg *msg = &entry->msg; /* ...followed by the old implementation of read_msi_msg_desc() */ } Possibly conditional on something like CONFIG_ARCH_NEEDS_SAVE_MSI_MSG. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.