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=-8.3 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 55B8BC10F14 for ; Tue, 15 Oct 2019 05:44:30 +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 C7BB4217F9 for ; Tue, 15 Oct 2019 05:44:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C7BB4217F9 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 46skrp6XbZzDqgV for ; Tue, 15 Oct 2019 16:44:26 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) 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 46skpg2NcQzDqX6 for ; Tue, 15 Oct 2019 16:42:33 +1100 (AEDT) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x9F5cR4d002727 for ; Tue, 15 Oct 2019 01:42:30 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2vn6m7jgfg-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 15 Oct 2019 01:42:30 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 15 Oct 2019 06:42:28 +0100 Received: from b06cxnps4076.portsmouth.uk.ibm.com (9.149.109.198) by e06smtp01.uk.ibm.com (192.168.101.131) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 15 Oct 2019 06:42:26 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x9F5gO1p47448302 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 15 Oct 2019 05:42:24 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4D1474C046; Tue, 15 Oct 2019 05:42:24 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AB9AA4C040; Tue, 15 Oct 2019 05:42:23 +0000 (GMT) Received: from ozlabs.au.ibm.com (unknown [9.192.253.14]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 15 Oct 2019 05:42:23 +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 CA379A00B2; Tue, 15 Oct 2019 16:42:20 +1100 (AEDT) Date: Tue, 15 Oct 2019 16:42:20 +1100 From: Sam Bobroff To: Frederic Barrat Subject: Re: [EXTERNAL] [RFC PATCH] powernv/eeh: Fix oops when probing cxl devices References: <20190927124510.15518-1-fbarrat@linux.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="jI8keyz6grp/JLjh" Content-Disposition: inline In-Reply-To: <20190927124510.15518-1-fbarrat@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-TM-AS-GCONF: 00 x-cbid: 19101505-4275-0000-0000-0000037223D6 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19101505-4276-0000-0000-00003885345A Message-Id: <20191015054219.GA16918@osmium> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-10-15_03:, , 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-1910150050 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" --jI8keyz6grp/JLjh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Sep 27, 2019 at 02:45:10PM +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 > Fixes: b905f8cdca77 ("powerpc/eeh: EEH for pSeries hot plug") > Signed-off-by: Frederic Barrat > --- >=20 > Sending as an RFC, as I'm afraid of hiding potential issues and would > be interested in comments. The powernv eeh code expects a struct > pci_dn, so the fix seems safe. I'm wondering if there could be cases > (other than capi virtual devices) where we'd want to blow up and fix > instead of going undetected with this patch. Looks good to me. I do think it would be good to detect a missing pci_dn (WARN_ONCE() might be appropriate). However to implement it, pnv_pcibios_bus_add_device() would need a way to detect that a struct pci_dev is a cxl virtual device. I don't see an easy way to do that; do you know if it's possible? One last thing: pseries_pcibios_bus_add_device() also requires a pci_dn. Do you know if it's possible to trigger a similar issue there, or is it not possible for some reason? Cheers, Sam. > 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 --jI8keyz6grp/JLjh Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEELWWF8pdtWK5YQRohMX8w6AQl/iIFAl2lXDUACgkQMX8w6AQl /iJBCAgAksTjVyjxKcuASc9gGa03XuQk5+jtvOg1k7setPdSjRGuDBdRCc4RMHc+ YwehN9IWUzNh8iOQmJcsTVI1tLM/lWSXcaF528cCKanH0mDS5v/G6Ax1d3czsySQ dzqCzFB8q6/Rnlb93G3HRS3YXdAqYq4hpM4q7nSLBqI/jKVryfCDdU4x/uPJmLhl xVG9RbSASyNJL70timUA7Sr5CowMrH+U1rP1Pk2rwxObGP3PkgLkpUNOByPxhBHH kQnyN1w3cvJE96ZckD1q2tkafZzHvM1S1xNUJl4kZIs+imGT1oTFUn5y5DTr9pX4 KruvAzfIyEQaYaTYUGfyvHd9rmqjgA== =SJDD -----END PGP SIGNATURE----- --jI8keyz6grp/JLjh--