From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f197.google.com (mail-ua0-f197.google.com [209.85.217.197]) by kanga.kvack.org (Postfix) with ESMTP id 9E6576B000A for ; Mon, 30 Jul 2018 23:08:54 -0400 (EDT) Received: by mail-ua0-f197.google.com with SMTP id g9-v6so4659982uam.17 for ; Mon, 30 Jul 2018 20:08:54 -0700 (PDT) Received: from userp2120.oracle.com (userp2120.oracle.com. [156.151.31.85]) by mx.google.com with ESMTPS id 4-v6si5780811vkg.117.2018.07.30.20.08.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Jul 2018 20:08:53 -0700 (PDT) Subject: Re: [PATCH] ipc/shm.c add ->pagesize function to shm_vm_ops References: <20180727211727.5020-1-jane.chu@oracle.com> <20180730164459.zduhnk7itoldqnom@linux-r8p5> From: Jane Chu Message-ID: Date: Mon, 30 Jul 2018 20:08:48 -0700 MIME-Version: 1.0 In-Reply-To: <20180730164459.zduhnk7itoldqnom@linux-r8p5> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, dan.j.williams@intel.com, mhocko@suse.com, jack@suse.cz, jglisse@redhat.com, mike.kravetz@oracle.com, linux-mm@kvack.org, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org Hi, Davidlohr, On 7/30/2018 9:44 AM, Davidlohr Bueso wrote: > On Fri, 27 Jul 2018, Jane Chu wrote: > >> Commit 05ea88608d4e13 (mm, hugetlbfs: introduce ->pagesize() to >> vm_operations_struct) adds a new ->pagesize() function to >> hugetlb_vm_ops, intended to cover all hugetlbfs backed files. >> >> With System V shared memory model, if "huge page" is specified, >> the "shared memory" is backed by hugetlbfs files, but the mappings >> initiated via shmget/shmat have their original vm_ops overwritten >> with shm_vm_ops, so we need to add a ->pagesize function to shm_vm_ops. >> Otherwise, vma_kernel_pagesize() returns PAGE_SIZE given a hugetlbfs >> backed vma, result in below BUG: >> >> fs/hugetlbfs/inode.c >> A A A A A A 443A A A A A A A A A A A A if (unlikely(page_mapped(page))) { >> A A A A A A 444A A A A A A A A A A A A A A A A A A A A BUG_ON(truncate_op); >> >> [A 242.268342] hugetlbfs: oracle (4592): Using mlock ulimits for >> SHM_HUGETLB is deprecated >> [A 282.653208] ------------[ cut here ]------------ >> [A 282.708447] kernel BUG at fs/hugetlbfs/inode.c:444! >> [A 282.818957] Modules linked in: nfsv3 rpcsec_gss_krb5 nfsv4 ... >> [A 284.025873] CPU: 35 PID: 5583 Comm: oracle_5583_sbt Not tainted >> 4.14.35-1829.el7uek.x86_64 #2 >> [A 284.246609] task: ffff9bf0507aaf80 task.stack: ffffa9e625628000 >> [A 284.317455] RIP: 0010:remove_inode_hugepages+0x3db/0x3e2 >> .... >> [A 285.292389] Call Trace: >> [A 285.321630]A hugetlbfs_evict_inode+0x1e/0x3e >> [A 285.372707]A evict+0xdb/0x1af >> [A 285.408185]A iput+0x1a2/0x1f7 >> [A 285.443661]A dentry_unlink_inode+0xc6/0xf0 >> [A 285.492661]A __dentry_kill+0xd8/0x18d >> [A 285.536459]A dput+0x1b5/0x1ed >> [A 285.571939]A __fput+0x18b/0x216 >> [A 285.609495]A ____fput+0xe/0x10 >> [A 285.646030]A task_work_run+0x90/0xa7 >> [A 285.688788]A exit_to_usermode_loop+0xdd/0x116 >> [A 285.740905]A do_syscall_64+0x187/0x1ae >> [A 285.785740]A entry_SYSCALL_64_after_hwframe+0x150/0x0 >> >> Suggested-by: Mike Kravetz >> Signed-off-by: Jane Chu > > Acked-by: Davidlohr Bueso Thank you! -jane