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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 D6E11CA9EC5 for ; Wed, 30 Oct 2019 12:59:02 +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 8C8792080F for ; Wed, 30 Oct 2019 12:59:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8C8792080F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au 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 4737nH3RyHzF4Ms for ; Wed, 30 Oct 2019 23:58:59 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4736qp6JCCzF4CD for ; Wed, 30 Oct 2019 23:16:06 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Received: by ozlabs.org (Postfix, from userid 1034) id 4736qp4MGXz9sPq; Wed, 30 Oct 2019 23:16:06 +1100 (AEDT) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: a8a30219ba78b1abb92091102b632f8e9bbdbf03 In-Reply-To: <20191016162833.22509-1-fbarrat@linux.ibm.com> To: Frederic Barrat , sbobroff@linux.ibm.com, linuxppc-dev@lists.ozlabs.org From: Michael Ellerman Subject: Re: [PATCH] powernv/eeh: Fix oops when probing cxl devices Message-Id: <4736qp4MGXz9sPq@ozlabs.org> Date: Wed, 30 Oct 2019 23:16:06 +1100 (AEDT) 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, andrew.donnellan@au1.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, 2019-10-16 at 16:28:33 UTC, 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: > > 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 [cxl] > [c000200e43983b00] [c00800001c4242ac] cxl_probe+0x504/0x5b0 [cxl] > [c000200e43983bb0] [c0000000006bba1c] local_pci_probe+0x6c/0x110 > [c000200e43983c30] [c000000000159278] work_for_cpu_fn+0x38/0x60 > > 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. > > 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. > > This patch fixes it by skipping adding EEH support on powernv for > devices which don't have a pci_dn structure. > > The cxl driver doesn't create virtual devices on pseries so this patch > doesn't fix it there intentionally. > > Fixes: b905f8cdca77 ("powerpc/eeh: EEH for pSeries hot plug") > Signed-off-by: Frederic Barrat Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/a8a30219ba78b1abb92091102b632f8e9bbdbf03 cheers