From patchwork Mon Dec 12 16:35:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 705090 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3tcpNw43hhz9t37 for ; Tue, 13 Dec 2016 03:35:44 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932388AbcLLQf0 (ORCPT ); Mon, 12 Dec 2016 11:35:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:49122 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932269AbcLLQfY (ORCPT ); Mon, 12 Dec 2016 11:35:24 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 68D31AC4D; Mon, 12 Dec 2016 16:35:19 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 7E1321E0D83; Mon, 12 Dec 2016 17:35:18 +0100 (CET) Date: Mon, 12 Dec 2016 17:35:18 +0100 From: Jan Kara To: kernel test robot Cc: Jan Kara , Theodore Ts'o , LKML , linux-ext4@vger.kernel.org, lkp@01.org, Ross Zwisler , linux-nvdimm@lists.01.org, Dave Chinner Subject: Re: [ext4] e2ae766c1b: BUG:sleeping_function_called_from_invalid_context_at_kernel/locking/rwsem.c Message-ID: <20161212163518.GA20728@quack2.suse.cz> References: <20161212101321.GA37214@inn.lkp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20161212101321.GA37214@inn.lkp.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Mon 12-12-16 18:13:21, kernel test robot wrote: > FYI, we noticed the following commit: > > commit: e2ae766c1b030271b5099b25674e2131d1d1e8c1 ("ext4: convert DAX faults to iomap infrastructure") > https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev > > in testcase: nvml > with following parameters: > > group: vmem > test: pmem > nr_pmem: 1 > fs: ext4 > mount_option: dax > > > > on test machine: 64 threads Intel(R) Xeon(R) CPU E5-4650 0 @ 2.70GHz with 64G memory > > caused below changes: > > > +------------------------------------------------+------------+------------+ > | | 96f8ba3dd6 | e2ae766c1b | > +------------------------------------------------+------------+------------+ > | boot_successes | 2 | 2 | > | boot_failures | 2 | 2 | > | BUG:kernel_hang_in_test_stage | 2 | | > | WARNING:at_fs/sysfs/dir.c:#sysfs_warn_dup | 0 | 2 | > | calltrace:parport_pc_init | 0 | 2 | > | calltrace:SyS_finit_module | 0 | 2 | > | WARNING:at_lib/kobject.c:#kobject_add_internal | 0 | 2 | > +------------------------------------------------+------------+------------+ > > > > user :notice: [ 325.592182] vmem_aligned_alloc/TEST1: SETUP (check/pmem/debug) > > user :notice: [ 325.603973] vmem_aligned_alloc/TEST1: START: vmem_aligned_alloc > kern :err : [ 325.608906] BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:51 > kern :err : [ 325.608908] in_atomic(): 1, irqs_disabled(): 0, pid: 24813, name: vmem_aligned_al > kern :warn : [ 325.608914] CPU: 44 PID: 24813 Comm: vmem_aligned_al Tainted: G O 4.9.0-rc4-00045-ge2ae766 #1 > kern :warn : [ 325.608916] Hardware name: Intel Corporation LH Pass/S4600LH...., BIOS SE5C600.86B.99.02.1047.032320122259 03/23/2012 > kern :warn : [ 325.608922] ffffc9002c1f7be0 > kern :warn : [ 325.608923] ffffffff81466af9 > kern :warn : [ 325.608924] ffff880fea2425c0 I think this is actually a bug introduced by Ross' PMD support. Attached patch should fix it. Ross, can you check it please? Honza Reviewed-by: Ross Zwisler Tested-by: "Huang, Ying" From c3d67dc7543abc03161f6cf357039ad9e56783ca Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 12 Dec 2016 16:32:23 +0100 Subject: [PATCH] dax: Fix sleep in atomic contex in grab_mapping_entry() Commit 7b5b8c9c4ac9 "dax: add struct iomap based DAX PMD support" has introduced unmapping of page tables if huge page needs to be split in grab_mapping_entry(). However the unmapping happens after radix_tree_preload() call which disables preemption and thus unmap_mapping_range() tries to acquire i_mmap_lock in atomic context which is a bug. Fix the problem by moving unmapping before radix_tree_preload() call. Fixes: 7b5b8c9c4ac9716fe9d77ec56ae5d962192ba030 Signed-off-by: Jan Kara --- fs/dax.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 51b03e91d3e2..5c74f60d0a50 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -351,14 +351,6 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, } spin_unlock_irq(&mapping->tree_lock); - err = radix_tree_preload( - mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); - if (err) { - if (pmd_downgrade) - put_locked_mapping_entry(mapping, index, entry); - return ERR_PTR(err); - } - /* * Besides huge zero pages the only other thing that gets * downgraded are empty entries which don't need to be @@ -368,6 +360,13 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, unmap_mapping_range(mapping, (index << PAGE_SHIFT) & PMD_MASK, PMD_SIZE, 0); + err = radix_tree_preload( + mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); + if (err) { + if (pmd_downgrade) + put_locked_mapping_entry(mapping, index, entry); + return ERR_PTR(err); + } spin_lock_irq(&mapping->tree_lock); if (pmd_downgrade) { -- 2.10.2