From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 617DBC07E85 for ; Sun, 9 Dec 2018 21:56:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F0A020837 for ; Sun, 9 Dec 2018 21:56:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F0A020837 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726930AbeLIV4F (ORCPT ); Sun, 9 Dec 2018 16:56:05 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36032 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726704AbeLIVzf (ORCPT ); Sun, 9 Dec 2018 16:55:35 -0500 Received: from pub.yeoldevic.com ([81.174.156.145] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gW72x-0002il-RL; Sun, 09 Dec 2018 21:55:32 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gW72i-0003b8-Vu; Sun, 09 Dec 2018 21:55:16 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "syzbot" , "Joel Fernandes (Google)" , "NeilBrown" , "Hugh Dickins" , "Peter Zijlstra" , "Matthew Wilcox" , "Greg Kroah-Hartman" Date: Sun, 09 Dec 2018 21:50:33 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 259/328] mm: shmem.c: Correctly annotate new inodes for lockdep In-Reply-To: X-SA-Exim-Connect-IP: 81.174.156.145 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "Joel Fernandes (Google)" commit b45d71fb89ab8adfe727b9d0ee188ed58582a647 upstream. Directories and inodes don't necessarily need to be in the same lockdep class. For ex, hugetlbfs splits them out too to prevent false positives in lockdep. Annotate correctly after new inode creation. If its a directory inode, it will be put into a different class. This should fix a lockdep splat reported by syzbot: > ====================================================== > WARNING: possible circular locking dependency detected > 4.18.0-rc8-next-20180810+ #36 Not tainted > ------------------------------------------------------ > syz-executor900/4483 is trying to acquire lock: > 00000000d2bfc8fe (&sb->s_type->i_mutex_key#9){++++}, at: inode_lock > include/linux/fs.h:765 [inline] > 00000000d2bfc8fe (&sb->s_type->i_mutex_key#9){++++}, at: > shmem_fallocate+0x18b/0x12e0 mm/shmem.c:2602 > > but task is already holding lock: > 0000000025208078 (ashmem_mutex){+.+.}, at: ashmem_shrink_scan+0xb4/0x630 > drivers/staging/android/ashmem.c:448 > > which lock already depends on the new lock. > > -> #2 (ashmem_mutex){+.+.}: > __mutex_lock_common kernel/locking/mutex.c:925 [inline] > __mutex_lock+0x171/0x1700 kernel/locking/mutex.c:1073 > mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088 > ashmem_mmap+0x55/0x520 drivers/staging/android/ashmem.c:361 > call_mmap include/linux/fs.h:1844 [inline] > mmap_region+0xf27/0x1c50 mm/mmap.c:1762 > do_mmap+0xa10/0x1220 mm/mmap.c:1535 > do_mmap_pgoff include/linux/mm.h:2298 [inline] > vm_mmap_pgoff+0x213/0x2c0 mm/util.c:357 > ksys_mmap_pgoff+0x4da/0x660 mm/mmap.c:1585 > __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] > __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline] > __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > -> #1 (&mm->mmap_sem){++++}: > __might_fault+0x155/0x1e0 mm/memory.c:4568 > _copy_to_user+0x30/0x110 lib/usercopy.c:25 > copy_to_user include/linux/uaccess.h:155 [inline] > filldir+0x1ea/0x3a0 fs/readdir.c:196 > dir_emit_dot include/linux/fs.h:3464 [inline] > dir_emit_dots include/linux/fs.h:3475 [inline] > dcache_readdir+0x13a/0x620 fs/libfs.c:193 > iterate_dir+0x48b/0x5d0 fs/readdir.c:51 > __do_sys_getdents fs/readdir.c:231 [inline] > __se_sys_getdents fs/readdir.c:212 [inline] > __x64_sys_getdents+0x29f/0x510 fs/readdir.c:212 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > -> #0 (&sb->s_type->i_mutex_key#9){++++}: > lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924 > down_write+0x8f/0x130 kernel/locking/rwsem.c:70 > inode_lock include/linux/fs.h:765 [inline] > shmem_fallocate+0x18b/0x12e0 mm/shmem.c:2602 > ashmem_shrink_scan+0x236/0x630 drivers/staging/android/ashmem.c:455 > ashmem_ioctl+0x3ae/0x13a0 drivers/staging/android/ashmem.c:797 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > other info that might help us debug this: > > Chain exists of: > &sb->s_type->i_mutex_key#9 --> &mm->mmap_sem --> ashmem_mutex > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(ashmem_mutex); > lock(&mm->mmap_sem); > lock(ashmem_mutex); > lock(&sb->s_type->i_mutex_key#9); > > *** DEADLOCK *** > > 1 lock held by syz-executor900/4483: > #0: 0000000025208078 (ashmem_mutex){+.+.}, at: > ashmem_shrink_scan+0xb4/0x630 drivers/staging/android/ashmem.c:448 Link: http://lkml.kernel.org/r/20180821231835.166639-1-joel@joelfernandes.org Signed-off-by: Joel Fernandes (Google) Reported-by: syzbot Reviewed-by: NeilBrown Suggested-by: NeilBrown Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- mm/shmem.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1422,6 +1422,8 @@ static struct inode *shmem_get_inode(str mpol_shared_policy_init(&info->policy, NULL); break; } + + lockdep_annotate_inode_mutex_key(inode); } else shmem_free_inode(sb); return inode;