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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 C0107C433EF for ; Thu, 31 Mar 2022 06:26:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=DGaiHWvdYxXc1h4m51qelnHM8VMUvE2l8fZhFKREhlY=; b=fqmxMoDodmoU0C iINfomiIu1McAnw/P6FMfvodLD5vDUgtU9a8oT1wqGk/CTzCVKZjMEzkqcYX/Wrgnu9E8RiPXy4m+ RdC4EfEexbVaLavECZLQ35N0OHF9cVcsr6jLb2nmWHwTSViphRafgl/ynyojs6sfVGMJlJYXgIBJa LKBhNpJeJXmVt9qSSBuM82eDt7cjZylZzzeLxmtj4dDInJqoRzPLNJvv+K5ik8opvt2JNbSMgd8ZC lFxLtXPvqqJJD3QqlBxLMQz8mvnCFDNVoG3dJUWb76FzOrwS1w8KeIJop9xYk7t9TdPvQ2qfRrqrf rrXPunWzZYNkzpH3h6GA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nZoFJ-000rR7-TV; Thu, 31 Mar 2022 06:25:26 +0000 Received: from muru.com ([72.249.23.125]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nZoFG-000rPp-5s for linux-arm-kernel@lists.infradead.org; Thu, 31 Mar 2022 06:25:23 +0000 Received: from localhost (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 45FA080FA; Thu, 31 Mar 2022 06:23:13 +0000 (UTC) Date: Thu, 31 Mar 2022 09:25:20 +0300 From: Tony Lindgren To: Jason Gunthorpe Cc: Lu Baolu , Joerg Roedel , Christoph Hellwig , Ben Skeggs , Kevin Tian , Ashok Raj , Will Deacon , Robin Murphy , Alex Williamson , Eric Auger , Liu Yi L , Jacob jun Pan , David Airlie , Daniel Vetter , Thierry Reding , Jonathan Hunter , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Christoph Hellwig , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, regressions@lists.linux.dev 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> <20220330173323.GA2120790@nvidia.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220330173323.GA2120790@nvidia.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220330_232522_295832_43EAE42E X-CRM114-Status: GOOD ( 24.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, * Jason Gunthorpe [220330 17:31]: > On Wed, Mar 30, 2022 at 08:19:37PM +0300, Tony Lindgren wrote: > > > > > __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. > > That makes alot more sense > > > > Can you find the code that is the NULL deref? > > > > I can debug a bit more tomorrow. > > Looks like omap's omap_iommu_probe_device() is buggy, it returns 0 on > error paths: > > num_iommus = of_property_count_elems_of_size(dev->of_node, "iommus", > sizeof(phandle)); > if (num_iommus < 0) > return 0; > > This function needs to return an errno -ENODEV > > Otherwise it causes a NULL dev->iommu->iommu_dev and dev_iommu_ops() will > crash. You got it. This fixes the issue for me. Looks like the regression already happened earlier and recent changes just expose it. For reference, fix posted at: https://lore.kernel.org/linux-iommu/20220331062301.24269-1-tony@atomide.com/T/#u Regards, Tony _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel