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 Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5B948C433EF for ; Wed, 30 Mar 2022 17:19:44 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id E977641BE5; Wed, 30 Mar 2022 17:19:43 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id peBAsgr6r-5o; Wed, 30 Mar 2022 17:19:43 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp4.osuosl.org (Postfix) with ESMTPS id 86BD441B78; Wed, 30 Mar 2022 17:19:42 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 5CA60C001D; Wed, 30 Mar 2022 17:19:42 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 31528C0012 for ; Wed, 30 Mar 2022 17:19:41 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 103EA61272 for ; Wed, 30 Mar 2022 17:19:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9hrdic84Am2Y for ; Wed, 30 Mar 2022 17:19:40 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from muru.com (muru.com [72.249.23.125]) by smtp3.osuosl.org (Postfix) with ESMTP id 2E16460AB2 for ; Wed, 30 Mar 2022 17:19:39 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 7C50780FA; Wed, 30 Mar 2022 17:17:31 +0000 (UTC) Date: Wed, 30 Mar 2022 20:19:37 +0300 From: Tony Lindgren To: Jason Gunthorpe Subject: Re: [PATCH v4 8/9] iommu: Remove unused argument in is_attach_deferred Message-ID: References: <20220216025249.3459465-1-baolu.lu@linux.intel.com> <20220216025249.3459465-9-baolu.lu@linux.intel.com> <20220330142340.GA2111031@nvidia.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220330142340.GA2111031@nvidia.com> Cc: regressions@lists.linux.dev, David Airlie , Thierry Reding , Will Deacon , Christoph Hellwig , Ashok Raj , Jonathan Hunter , Christoph Hellwig , Ben Skeggs , Kevin Tian , Alex Williamson , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Jacob jun Pan , Daniel Vetter , Robin Murphy X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" * Jason Gunthorpe [220330 14:21]: > On Wed, Mar 30, 2022 at 05:00:39PM +0300, Tony Lindgren wrote: > > Hi, > > > > * Lu Baolu [700101 02:00]: > > > The is_attach_deferred iommu_ops callback is a device op. The domain > > > argument is unnecessary and never used. Remove it to make code clean. > > > > Looks like this causes a regression for at least drivers/iommu/omap-iommu.c. > > > > To me it seems the issue is there is no is_attach_deferred implemented, so > > we get a NULL pointer dereference at virtual address 00000008: > > > > __iommu_probe_device from probe_iommu_group+0x2c/0x38 > > probe_iommu_group from bus_for_each_dev+0x74/0xbc > > bus_for_each_dev from bus_iommu_probe+0x34/0x2e8 > > bus_iommu_probe from bus_set_iommu+0x80/0xc8 > > bus_set_iommu from omap_iommu_init+0x88/0xcc > > omap_iommu_init from do_one_initcall+0x44/0x24c > > > > Any ideas for a fix? > > > > It would be good to fix this quickly so we don't end up with a broken > > v5.18-rc1.. > > > > For reference, this is mainline commit 41bb23e70b50 ("iommu: Remove unused > > argument in is_attach_deferred"). > > Are you confident in the bisection? I don't see how that commit could > NULL deref.. Oops sorry you're right, the breaking commit is a different patch, it's 3f6634d997db ("iommu: Use right way to retrieve iommu_ops") instead. I must have picked the wrong commit while testing. > Can you find the code that is the NULL deref? I can debug a bit more tomorrow. Regards, Tony _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu