Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751586AbdGZNZK (ORCPT ); Wed, 26 Jul 2017 09:25:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57240 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750925AbdGZNZH (ORCPT ); Wed, 26 Jul 2017 09:25:07 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 1DE9B12B47 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=asavkov@redhat.com Date: Wed, 26 Jul 2017 15:25:05 +0200 From: Artem Savkov To: Joerg Roedel Cc: Thomas Gleixner , iommu@lists.linux-foundation.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iommu/amd: Fix schedule-while-atomic BUG in initialization code Message-ID: <20170726132505.cw4xmstcrbmuduyz@shodan.usersys.redhat.com> References: <20170725135618.hev4vj7w24gm3a5q@shodan.usersys.redhat.com> <20170726122614.GP15833@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170726122614.GP15833@8bytes.org> User-Agent: NeoMutt/20161126 (1.7.1) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 26 Jul 2017 13:25:07 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2087 Lines: 59 On Wed, Jul 26, 2017 at 02:26:14PM +0200, Joerg Roedel wrote: > Hi Artem, Thomas, > > On Wed, Jul 26, 2017 at 12:42:49PM +0200, Thomas Gleixner wrote: > > On Tue, 25 Jul 2017, Artem Savkov wrote: > > > > > Hi, > > > > > > Commit 1c3c5ea "sched/core: Enable might_sleep() and smp_processor_id() > > > checks early" seem to have uncovered an issue with amd-iommu/x2apic. > > > > > > Starting with that commit the following warning started to show up on AMD > > > systems during boot: > > > > > [ 0.160000] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747 > > > > > [ 0.160000] mutex_lock_nested+0x1b/0x20 > > > [ 0.160000] register_syscore_ops+0x1d/0x70 > > > [ 0.160000] state_next+0x119/0x910 > > > [ 0.160000] iommu_go_to_state+0x29/0x30 > > > [ 0.160000] amd_iommu_enable+0x13/0x23 > > > [ 0.160000] irq_remapping_enable+0x1b/0x39 > > > [ 0.160000] enable_IR_x2apic+0x91/0x196 > > > [ 0.160000] default_setup_apic_routing+0x16/0x6e > > > [ 0.160000] native_smp_prepare_cpus+0x257/0x2d5 > > Thanks for the report! > > > --- a/drivers/iommu/amd_iommu_init.c > > +++ b/drivers/iommu/amd_iommu_init.c > > @@ -2440,7 +2440,6 @@ static int __init state_next(void) > > break; > > case IOMMU_ACPI_FINISHED: > > early_enable_iommus(); > > - register_syscore_ops(&amd_iommu_syscore_ops); > > x86_platform.iommu_shutdown = disable_iommus; > > init_state = IOMMU_ENABLED; > > break; > > @@ -2559,6 +2558,8 @@ static int __init amd_iommu_init(void) > > for_each_iommu(iommu) > > iommu_flush_all_caches(iommu); > > } > > + } else { > > + register_syscore_ops(&amd_iommu_syscore_ops); > > } > > > > return ret; > > Yes, that should fix it, but I think its better to just move the > register_syscore_ops() call to a later initialization step, like in the > patch below. I tested it an will queue it to my iommu/fixes branch. Checked it as well just in case, didn't see any issues. Thank you. Reported-and-tested-by: Artem Savkov -- Regards, Artem