Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753443AbbGOS2o (ORCPT ); Wed, 15 Jul 2015 14:28:44 -0400 Received: from mail-ie0-f178.google.com ([209.85.223.178]:36630 "EHLO mail-ie0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752560AbbGOS2m (ORCPT ); Wed, 15 Jul 2015 14:28:42 -0400 MIME-Version: 1.0 In-Reply-To: <55A6658D.6030802@raptorengineeringinc.com> References: <1436935796-28995-1-git-send-email-Sreekanth.Reddy@avagotech.com> <20150715062456.GB19028@dhcp-135-24-192-118.lsi.com> <55A6658D.6030802@raptorengineeringinc.com> Date: Wed, 15 Jul 2015 11:28:41 -0700 X-Google-Sender-Auth: Gor7IY7VxLy-dYCppkkKmsbME5Y Message-ID: Subject: Re: [PATCH v3] [SCSI] mpt2sas, mpt3sas: Abort initialization if no memory I/O resources detected From: Yinghai Lu To: Timothy Pearson Cc: Sreekanth Reddy , James Bottomley , martin.petersen@oracle.com, Linux-Scsi , "James E.J. Bottomley" , Sathya.Prakash@avagotech.com, Linux Kernel Mailing List , Christoph Hellwig , Bjorn Helgaas , "linux-pci@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1156 Lines: 26 On Wed, Jul 15, 2015 at 6:52 AM, Timothy Pearson wrote: >> I have just kept the same description provide by Timothy in his >> initial patch. >> >> But I observe that their may be chance of getting "unable to handle >> kernel NULL pointer dereference" kernel panic if no Memory Resource >> available in the PCI subsystem. So agreed to the Timothy proposal of >> aborting the driver initialization if it doesn't detect any Memory >> resource instead of whole system get into panic state. >> > On some systems Linux is unable / unwilling to assign a BAR if the BIOS > does not assign one at startup. I didn't look into the Linux allocator > side of things in much detail, but it is quite possible that Linux is > unaware the device only has partial resources assigned. > Would be great if you can post boot log so we can figure about why those BARs are not assigned. Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/