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08 Nov 2018 17:06:51 -0600 Received: from pps.filterd (m0144103.ppops.net [127.0.0.1]) by mx0b-00154901.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wA8N2nol191906 for ; Thu, 8 Nov 2018 18:06:50 -0500 Received: from esa4.dell-outbound2.iphmx.com (esa4.dell-outbound2.iphmx.com [68.232.154.98]) by mx0b-00154901.pphosted.com with ESMTP id 2nmq3m2hmw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Thu, 08 Nov 2018 18:06:50 -0500 Received: from ausxippc101.us.dell.com ([143.166.85.207]) by esa4.dell-outbound2.iphmx.com with ESMTP/TLS/DHE-RSA-AES256-SHA256; 09 Nov 2018 05:06:49 +0600 X-LoopCount0: from 10.166.134.83 X-IronPort-AV: E=Sophos;i="5.54,481,1534827600"; d="scan'208";a="1159082747" From: To: Subject: Re: [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected Thread-Topic: [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected Thread-Index: AQHUT50UQ290XPGvJEGnaSTTjbCF+g== Date: Thu, 8 Nov 2018 23:06:47 +0000 Message-ID: <16bf9d14bc5f4a90b2b88dd2eb165186@ausx13mps321.AMER.DELL.COM> References: <20180918221501.13112-1-mr.nuke.me@gmail.com> <20181107234257.GC41183@google.com> <20181108200855.GE41183@google.com> <20181108220117.GA11466@kroah.com> <20181108223258.GD2932@localhost.localdomain> <20181108224255.GA20619@kroah.com> <20d68e586fff4dcca5616d5056f6fc21@ausx13mps321.AMER.DELL.COM> <20181108225109.GA3023@kroah.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.177.90.70] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-11-08_13:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1811080194 X-Mailman-Approved-At: Fri, 09 Nov 2018 13:29:42 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Shyam.Iyer@dell.com, sbobroff@linux.ibm.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, keith.busch@intel.com, lukas@wunner.de, helgaas@kernel.org, mr.nuke.me@gmail.com, Austin.Bolen@dell.com, oohall@gmail.com, linuxppc-dev@lists.ozlabs.org, jonathan.derrick@intel.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 11/08/2018 04:51 PM, Greg KH wrote:=0A= > On Thu, Nov 08, 2018 at 10:49:08PM +0000, Alex_Gagniuc@Dellteam.com wrote= :=0A= >> In the case that we're trying to fix, this code executing is a result of= =0A= >> the device being gone, so we can guarantee race-free operation. I agree= =0A= >> that there is a race, in the general case. As far as checking the result= =0A= >> for all F's, that's not an option when firmware crashes the system as a= =0A= >> result of the mmio read/write. It's never pretty when firmware gets=0A= >> involved.=0A= > =0A= > If you have firmware that crashes the system when you try to read from a= =0A= > PCI device that was hot-removed, that is broken firmware and needs to be= =0A= > fixed. The kernel can not work around that as again, you will never win= =0A= > that race.=0A= =0A= But it's not the firmware that crashes. It's linux as a result of a =0A= fatal error message from the firmware. And we can't fix that because FFS = =0A= handling requires that the system reboots [1].=0A= =0A= If we're going to say that we don't want to support FFS because it's a =0A= separate code path, and different flow, that's fine. I am myself, not a =0A= fan of FFS. But if we're going to continue supporting it, I think we'll =0A= continue to have to resolve these sort of unintended consequences.=0A= =0A= Alex=0A= =0A= [1] ACPI 6.2, 18.1 - Hardware Errors and Error Sources=0A=