From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id E5ECE6B02C3 for ; Tue, 8 Aug 2017 07:17:52 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id r62so29957254pfj.1 for ; Tue, 08 Aug 2017 04:17:52 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com. [148.163.156.1]) by mx.google.com with ESMTPS id m8si786630plk.673.2017.08.08.04.17.51 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 08 Aug 2017 04:17:51 -0700 (PDT) Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v78BH3tb106872 for ; Tue, 8 Aug 2017 07:17:51 -0400 Received: from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com [202.81.31.141]) by mx0a-001b2d01.pphosted.com with ESMTP id 2c7ay0n19y-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 08 Aug 2017 07:17:50 -0400 Received: from localhost by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 8 Aug 2017 21:17:48 +1000 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v78BHl5433292542 for ; Tue, 8 Aug 2017 21:17:47 +1000 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v78BHkW7011337 for ; Tue, 8 Aug 2017 21:17:46 +1000 Subject: Re: [RFC v5 05/11] mm: fix lock dependency against mapping->i_mmap_rwsem References: <1497635555-25679-1-git-send-email-ldufour@linux.vnet.ibm.com> <1497635555-25679-6-git-send-email-ldufour@linux.vnet.ibm.com> From: Anshuman Khandual Date: Tue, 8 Aug 2017 16:47:23 +0530 MIME-Version: 1.0 In-Reply-To: <1497635555-25679-6-git-send-email-ldufour@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Message-Id: <564749a2-a729-b927-7707-1cad897c418a@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour , paulmck@linux.vnet.ibm.com, peterz@infradead.org, akpm@linux-foundation.org, kirill@shutemov.name, ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com, Tim Chen On 06/16/2017 11:22 PM, Laurent Dufour wrote: > kworker/32:1/819 is trying to acquire lock: > (&vma->vm_sequence){+.+...}, at: [] > zap_page_range_single+0xd0/0x1a0 > > but task is already holding lock: > (&mapping->i_mmap_rwsem){++++..}, at: [] > unmap_mapping_range+0x7c/0x160 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #2 (&mapping->i_mmap_rwsem){++++..}: > down_write+0x84/0x130 > __vma_adjust+0x1f4/0xa80 > __split_vma.isra.2+0x174/0x290 > do_munmap+0x13c/0x4e0 > vm_munmap+0x64/0xb0 > elf_map+0x11c/0x130 > load_elf_binary+0x6f0/0x15f0 > search_binary_handler+0xe0/0x2a0 > do_execveat_common.isra.14+0x7fc/0xbe0 > call_usermodehelper_exec_async+0x14c/0x1d0 > ret_from_kernel_thread+0x5c/0x68 > > -> #1 (&vma->vm_sequence/1){+.+...}: > __vma_adjust+0x124/0xa80 > __split_vma.isra.2+0x174/0x290 > do_munmap+0x13c/0x4e0 > vm_munmap+0x64/0xb0 > elf_map+0x11c/0x130 > load_elf_binary+0x6f0/0x15f0 > search_binary_handler+0xe0/0x2a0 > do_execveat_common.isra.14+0x7fc/0xbe0 > call_usermodehelper_exec_async+0x14c/0x1d0 > ret_from_kernel_thread+0x5c/0x68 > > -> #0 (&vma->vm_sequence){+.+...}: > lock_acquire+0xf4/0x310 > unmap_page_range+0xcc/0xfa0 > zap_page_range_single+0xd0/0x1a0 > unmap_mapping_range+0x138/0x160 > truncate_pagecache+0x50/0xa0 > put_aio_ring_file+0x48/0xb0 > aio_free_ring+0x40/0x1b0 > free_ioctx+0x38/0xc0 > process_one_work+0x2cc/0x8a0 > worker_thread+0xac/0x580 > kthread+0x164/0x1b0 > ret_from_kernel_thread+0x5c/0x68 > > other info that might help us debug this: > > Chain exists of: > &vma->vm_sequence --> &vma->vm_sequence/1 --> &mapping->i_mmap_rwsem > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(&mapping->i_mmap_rwsem); > lock(&vma->vm_sequence/1); > lock(&mapping->i_mmap_rwsem); > lock(&vma->vm_sequence); > > *** DEADLOCK *** > > To fix that we must grab the vm_sequence lock after any mapping one in > __vma_adjust(). > > Signed-off-by: Laurent Dufour Should not this be folded back into the previous patch ? It fixes an issue introduced by the previous one. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org