Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753318AbbGOSqk (ORCPT ); Wed, 15 Jul 2015 14:46:40 -0400 Received: from pearsoncomputing.net ([192.119.205.242]:8594 "EHLO mail.pearsoncomputing.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752329AbbGOSqj (ORCPT ); Wed, 15 Jul 2015 14:46:39 -0400 DKIM-Filter: OpenDKIM Filter v2.9.2 mail.pearsoncomputing.net AA9FD640D81 Message-ID: <55A6AA89.60202@raptorengineeringinc.com> Date: Wed, 15 Jul 2015 13:46:33 -0500 From: Timothy Pearson User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100922 Thunderbird/3.1.4 MIME-Version: 1.0 To: Yinghai Lu 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" Subject: Re: [PATCH v3] [SCSI] mpt2sas, mpt3sas: Abort initialization if no memory I/O resources detected References: <1436935796-28995-1-git-send-email-Sreekanth.Reddy@avagotech.com> <20150715062456.GB19028@dhcp-135-24-192-118.lsi.com> <55A6658D.6030802@raptorengineeringinc.com> In-Reply-To: X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1536 Lines: 37 On 07/15/2015 01:28 PM, Yinghai Lu wrote: > 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 Unfortunately the systems exhibiting the issue were upgraded to a later BIOS that does not have this problem; it might be possible to set up a test system in the future but that probably won't happen for some time. -- Timothy Pearson Raptor Engineering +1 (415) 727-8645 http://www.raptorengineeringinc.com -- 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/