From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9A78ECE599 for ; Thu, 17 Oct 2019 03:00:55 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 63D83218DE for ; Thu, 17 Oct 2019 03:00:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63D83218DE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46tv791sYvzDqVj for ; Thu, 17 Oct 2019 14:00:53 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=sbobroff@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46tv4y071vzDr7h for ; Thu, 17 Oct 2019 13:58:57 +1100 (AEDT) Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x9H2vIpl111760 for ; Wed, 16 Oct 2019 22:58:52 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2vpbgpej7e-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 16 Oct 2019 22:58:52 -0400 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 17 Oct 2019 03:58:49 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x9H2wFk639321990 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 17 Oct 2019 02:58:16 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5B4ED52050; Thu, 17 Oct 2019 02:58:47 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id B08725204F; Thu, 17 Oct 2019 02:58:46 +0000 (GMT) Received: from osmium (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id 43586A024A; Thu, 17 Oct 2019 13:58:43 +1100 (AEDT) Date: Thu, 17 Oct 2019 13:58:42 +1100 From: Sam Bobroff To: Frederic Barrat Subject: Re: [PATCH] powernv/eeh: Fix oops when probing cxl devices References: <20191016162833.22509-1-fbarrat@linux.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="AhhlLboLdkugWU4S" Content-Disposition: inline In-Reply-To: <20191016162833.22509-1-fbarrat@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-TM-AS-GCONF: 00 x-cbid: 19101702-0008-0000-0000-00000322BE65 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19101702-0009-0000-0000-00004A41DA39 Message-Id: <20191017025841.GA18824@osmium> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-10-17_01:, , 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=8.0.1-1908290000 definitions=main-1910170020 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: clombard@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, andrew.donnellan@au1.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" --AhhlLboLdkugWU4S Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Oct 16, 2019 at 06:28:33PM +0200, Frederic Barrat wrote: > Recent cleanup in the way EEH support is added to a device causes a > kernel oops when the cxl driver probes a device and creates virtual > devices discovered on the FPGA: >=20 > BUG: Kernel NULL pointer dereference at 0x000000a0 > Faulting instruction address: 0xc000000000048070 > Oops: Kernel access of bad area, sig: 7 [#1] > ... > NIP [c000000000048070] eeh_add_device_late.part.9+0x50/0x1e0 > LR [c00000000004805c] eeh_add_device_late.part.9+0x3c/0x1e0 > Call Trace: > [c000200e43983900] [c00000000079e250] _dev_info+0x5c/0x6c (unreliable) > [c000200e43983980] [c0000000000d1ad0] pnv_pcibios_bus_add_device+0x60= /0xb0 > [c000200e439839f0] [c0000000000606d0] pcibios_bus_add_device+0x40/0x60 > [c000200e43983a10] [c0000000006aa3a0] pci_bus_add_device+0x30/0x100 > [c000200e43983a80] [c0000000006aa4d4] pci_bus_add_devices+0x64/0xd0 > [c000200e43983ac0] [c00800001c429118] cxl_pci_vphb_add+0xe0/0x130 [cx= l] > [c000200e43983b00] [c00800001c4242ac] cxl_probe+0x504/0x5b0 [cxl] > [c000200e43983bb0] [c0000000006bba1c] local_pci_probe+0x6c/0x110 > [c000200e43983c30] [c000000000159278] work_for_cpu_fn+0x38/0x60 >=20 > The root cause is that those cxl virtual devices don't have a > representation in the device tree and therefore no associated pci_dn > structure. In eeh_add_device_late(), pdn is NULL, so edev is NULL and > we oops. >=20 > We never had explicit support for EEH for those virtual > devices. Instead, EEH events are reported to the (real) pci device and > handled by the cxl driver. Which can then forward to the virtual > devices and handle dependencies. The fact that we try adding EEH > support for the virtual devices is new and a side-effect of the recent > cleanup. >=20 > This patch fixes it by skipping adding EEH support on powernv for > devices which don't have a pci_dn structure. >=20 > The cxl driver doesn't create virtual devices on pseries so this patch > doesn't fix it there intentionally. >=20 > Fixes: b905f8cdca77 ("powerpc/eeh: EEH for pSeries hot plug") > Signed-off-by: Frederic Barrat > --- >=20 > Sam: I'm resubmitting indentically as the RFC after all. I couldn't > find a clean way to separate the non-capi virtual device case to print > a warning and I'm a bit reluctant to make heavy changes for that. >=20 > Support for cxl on pseries has been bit-rotting for a while and > because of that, we don't create virtual devices there. So I didn't > touch the pseries path. At least on pseries, if there's another > unexpected case where the pdn is NULL, we should catch it more easily > with the oops message. OK. I agree that it's not worth doing more. Reviewed-by: Sam Bobroff > arch/powerpc/platforms/powernv/eeh-powernv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/= platforms/powernv/eeh-powernv.c > index 6bc24a47e9ef..6f300ab7f0e9 100644 > --- a/arch/powerpc/platforms/powernv/eeh-powernv.c > +++ b/arch/powerpc/platforms/powernv/eeh-powernv.c > @@ -42,7 +42,7 @@ void pnv_pcibios_bus_add_device(struct pci_dev *pdev) > { > struct pci_dn *pdn =3D pci_get_pdn(pdev); > =20 > - if (eeh_has_flag(EEH_FORCE_DISABLED)) > + if (!pdn || eeh_has_flag(EEH_FORCE_DISABLED)) > return; > =20 > dev_dbg(&pdev->dev, "EEH: Setting up device\n"); > --=20 > 2.21.0 >=20 --AhhlLboLdkugWU4S Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEELWWF8pdtWK5YQRohMX8w6AQl/iIFAl2n2NkACgkQMX8w6AQl /iImFQf+JSGQ2R/tlPonut7EwfjbDUzCAy77Ne35nomC8l+LmmpOLsaV920F/M3G ru+ruPKT89bkN7/3E1TumwCFtWEob1PRxd7LjcTox01xc6MSa4zlN+SG+Ca5Qy2a wv8BlSCkGHzZJJP2JK8musQeqVv6ZyLsvhPW6OVLCt5JOMWbr9wU8Lkuf2rN3ZoI jS5u8g3edu7mxyOS4f6GDU8A6kRUDhxY6TJ20UtgUsPbeYXEa0ByhpN0NqPEPwde sheFRMRNOm3uk1RvkRtGJG0rwcuIWs8XI7VZ2sWe7Djx4I+Olry1d4rgxPwmOj81 nxGs6qdF4YhF2/NODDU8/bgryIMZ4w== =6K0N -----END PGP SIGNATURE----- --AhhlLboLdkugWU4S--