From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f70.google.com (mail-it0-f70.google.com [209.85.214.70]) by kanga.kvack.org (Postfix) with ESMTP id B4BC96B0333 for ; Mon, 27 Mar 2017 02:24:06 -0400 (EDT) Received: by mail-it0-f70.google.com with SMTP id 133so58868106itu.17 for ; Sun, 26 Mar 2017 23:24:06 -0700 (PDT) Received: from out0-158.mail.aliyun.com (out0-158.mail.aliyun.com. [140.205.0.158]) by mx.google.com with ESMTP id f16si3560709plj.212.2017.03.26.23.24.05 for ; Sun, 26 Mar 2017 23:24:05 -0700 (PDT) Reply-To: "Hillf Danton" From: "Hillf Danton" References: <1490477850-7944-1-git-send-email-mike.kravetz@oracle.com> In-Reply-To: <1490477850-7944-1-git-send-email-mike.kravetz@oracle.com> Subject: Re: [PATCH v2] hugetlbfs: initialize shared policy as part of inode allocation Date: Mon, 27 Mar 2017 14:24:00 +0800 Message-ID: <016101d2a6c2$b98e9080$2cabb180$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: 'Mike Kravetz' , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: 'Dmitry Vyukov' , 'Tetsuo Handa' , 'Michal Hocko' , 'Dave Hansen' , 'Andrew Morton' On March 26, 2017 5:38 AM Mike Kravetz wrote: > > Any time after inode allocation, destroy_inode can be called. The > hugetlbfs inode contains a shared_policy structure, and > mpol_free_shared_policy is unconditionally called as part of > hugetlbfs_destroy_inode. Initialize the policy as part of inode > allocation so that any quick (error path) calls to destroy_inode > will be handed an initialized policy. > > syzkaller fuzzer found this bug, that resulted in the following: > > BUG: KASAN: user-memory-access in atomic_inc > include/asm-generic/atomic-instrumented.h:87 [inline] at addr > 000000131730bd7a > BUG: KASAN: user-memory-access in __lock_acquire+0x21a/0x3a80 > kernel/locking/lockdep.c:3239 at addr 000000131730bd7a > Write of size 4 by task syz-executor6/14086 > CPU: 3 PID: 14086 Comm: syz-executor6 Not tainted 4.11.0-rc3+ #364 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:16 [inline] > dump_stack+0x1b8/0x28d lib/dump_stack.c:52 > kasan_report_error mm/kasan/report.c:291 [inline] > kasan_report.part.2+0x34a/0x480 mm/kasan/report.c:316 > kasan_report+0x21/0x30 mm/kasan/report.c:303 > check_memory_region_inline mm/kasan/kasan.c:326 [inline] > check_memory_region+0x137/0x190 mm/kasan/kasan.c:333 > kasan_check_write+0x14/0x20 mm/kasan/kasan.c:344 > atomic_inc include/asm-generic/atomic-instrumented.h:87 [inline] > __lock_acquire+0x21a/0x3a80 kernel/locking/lockdep.c:3239 > lock_acquire+0x1ee/0x590 kernel/locking/lockdep.c:3762 > __raw_write_lock include/linux/rwlock_api_smp.h:210 [inline] > _raw_write_lock+0x33/0x50 kernel/locking/spinlock.c:295 > mpol_free_shared_policy+0x43/0xb0 mm/mempolicy.c:2536 > hugetlbfs_destroy_inode+0xca/0x120 fs/hugetlbfs/inode.c:952 > alloc_inode+0x10d/0x180 fs/inode.c:216 > new_inode_pseudo+0x69/0x190 fs/inode.c:889 > new_inode+0x1c/0x40 fs/inode.c:918 > hugetlbfs_get_inode+0x40/0x420 fs/hugetlbfs/inode.c:734 > hugetlb_file_setup+0x329/0x9f0 fs/hugetlbfs/inode.c:1282 > newseg+0x422/0xd30 ipc/shm.c:575 > ipcget_new ipc/util.c:285 [inline] > ipcget+0x21e/0x580 ipc/util.c:639 > SYSC_shmget ipc/shm.c:673 [inline] > SyS_shmget+0x158/0x230 ipc/shm.c:657 > entry_SYSCALL_64_fastpath+0x1f/0xc2 > > Analysis provided by Tetsuo Handa > v2: Remove now redundant initialization in hugetlbfs_get_root > > Reported-by: Dmitry Vyukov > Signed-off-by: Mike Kravetz > --- Acked-by: Hillf Danton -- 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