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=-0.7 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 54B52C4321A for ; Fri, 26 Apr 2019 00:07:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 33392206A3 for ; Fri, 26 Apr 2019 00:07:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728476AbfDZAHH (ORCPT ); Thu, 25 Apr 2019 20:07:07 -0400 Received: from mail-io1-f69.google.com ([209.85.166.69]:51260 "EHLO mail-io1-f69.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726766AbfDZAHH (ORCPT ); Thu, 25 Apr 2019 20:07:07 -0400 Received: by mail-io1-f69.google.com with SMTP id y18so1341462ior.18 for ; Thu, 25 Apr 2019 17:07:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=fAgF82Ea2Le34CGlmCfmPkgW8wzL1xNX4ul2vnGLbqg=; b=rbOY0qElUP+NHYjQVvtMyjWe4Bf74OEcKTibqkJq4ji7Y+28ze0/mzA0BtaxSGoeK4 RkC0/4ppRsOJvQxcPNvw8pNNtjfR42+f8PlsMGW7+XoZMGhWLM5hzOds3kLjHQ4DzDkB ide63955b4SpWnPw+uSZZ1E7XQRjf+StNWQzSVrRzeMebhmN3orNhHhX0CkO/t0IRoHX uhzXCTt/36Fn1klibboIOGnXv1KoxBqcN9dIqjeM4pjzd0HtkmfyvHVJLSVZOnzIdQKR JBAhM9ghUjrRaCFcEGDD8Y30OVdTCg/S849GXXv4ixDQN7SNITDU1ut2Obr5SUWDTgr0 Zzrg== X-Gm-Message-State: APjAAAVOU57okcgG48oODjEIJ6Ncs6qUvq9oUeGzyjZwmJiH7sVJK68V TAGKp7RwPux+bl8C7kNxu+MCEaczsUAIuOjHo6Lu0F3uYU++ X-Google-Smtp-Source: APXvYqx1+KWaM23X4Gts3o/eoZTfzNtcpuot+WCHclkmMhxL+rboqKmGXe1Skygd2TLpPvIdPNM3o2IImEZOGY3PH4fzPBlN0WW8 MIME-Version: 1.0 X-Received: by 2002:a02:9108:: with SMTP id a8mr12061074jag.107.1556237226085; Thu, 25 Apr 2019 17:07:06 -0700 (PDT) Date: Thu, 25 Apr 2019 17:07:06 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000000c1b5b058763b7b9@google.com> Subject: possible deadlock in do_io_accounting (2) From: syzbot To: adobriyan@gmail.com, akpm@linux-foundation.org, casey@schaufler-ca.com, keescook@chromium.org, kent.overstreet@gmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mhocko@suse.com, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 085b7755 Linux 5.1-rc6 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=132444f4a00000 kernel config: https://syzkaller.appspot.com/x/.config?x=a42d110b47dd6b36 dashboard link: https://syzkaller.appspot.com/bug?extid=d7d7de240978094ce2ef compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+d7d7de240978094ce2ef@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 5.1.0-rc6 #79 Not tainted ------------------------------------------------------ syz-executor.5/18117 is trying to acquire lock: 00000000d18ffe87 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting+0x1f4/0x830 fs/proc/base.c:2740 but task is already holding lock: 00000000229ae1ca (&p->lock){+.+.}, at: seq_read+0x71/0x1130 fs/seq_file.c:161 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 seq_read+0x71/0x1130 fs/seq_file.c:161 proc_reg_read+0x1fe/0x2c0 fs/proc/inode.c:227 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:922 vfs_readv+0xf0/0x160 fs/read_write.c:984 kernel_readv fs/splice.c:358 [inline] default_file_splice_read+0x475/0x890 fs/splice.c:413 do_splice_to+0x12a/0x190 fs/splice.c:876 splice_direct_to_actor+0x2d2/0x970 fs/splice.c:953 do_splice_direct+0x1da/0x2a0 fs/splice.c:1062 do_sendfile+0x597/0xd00 fs/read_write.c:1443 __do_sys_sendfile64 fs/read_write.c:1504 [inline] __se_sys_sendfile64 fs/read_write.c:1490 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1490 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (sb_writers#3){.+.+}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 percpu_down_read include/linux/percpu-rwsem.h:36 [inline] __sb_start_write+0x20b/0x360 fs/super.c:1613 sb_start_write include/linux/fs.h:1621 [inline] mnt_want_write+0x3f/0xc0 fs/namespace.c:358 ovl_want_write+0x76/0xa0 fs/overlayfs/util.c:24 ovl_create_object+0xb3/0x2c0 fs/overlayfs/dir.c:599 ovl_create+0x28/0x30 fs/overlayfs/dir.c:630 lookup_open+0x12e0/0x1b10 fs/namei.c:3232 do_last fs/namei.c:3322 [inline] path_openat+0x14ac/0x46e0 fs/namei.c:3533 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_sys_open+0x3fe/0x5d0 fs/open.c:1069 __do_sys_open fs/open.c:1087 [inline] __se_sys_open fs/open.c:1082 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1082 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_dir_key[depth]){++++}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 down_read+0x3b/0x90 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:782 [inline] do_last fs/namei.c:3321 [inline] path_openat+0x1e98/0x46e0 fs/namei.c:3533 do_filp_open+0x1a1/0x280 fs/namei.c:3563 do_open_execat+0x137/0x690 fs/exec.c:856 __do_execve_file.isra.0+0x178d/0x23f0 fs/exec.c:1758 do_execveat_common fs/exec.c:1865 [inline] do_execve fs/exec.c:1882 [inline] __do_sys_execve fs/exec.c:1958 [inline] __se_sys_execve fs/exec.c:1953 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1953 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: check_prevs_add kernel/locking/lockdep.c:2333 [inline] validate_chain kernel/locking/lockdep.c:2714 [inline] __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072 mutex_lock_killable_nested+0x16/0x20 kernel/locking/mutex.c:1102 do_io_accounting+0x1f4/0x830 fs/proc/base.c:2740 proc_tid_io_accounting+0x20/0x30 fs/proc/base.c:2783 proc_single_show+0xf6/0x170 fs/proc/base.c:744 seq_read+0x4db/0x1130 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:922 vfs_readv+0xf0/0x160 fs/read_write.c:984 do_preadv+0x1c4/0x280 fs/read_write.c:1068 __do_sys_preadv fs/read_write.c:1118 [inline] __se_sys_preadv fs/read_write.c:1113 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1113 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#3); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 1 lock held by syz-executor.5/18117: #0: 00000000229ae1ca (&p->lock){+.+.}, at: seq_read+0x71/0x1130 fs/seq_file.c:161 stack backtrace: CPU: 1 PID: 18117 Comm: syz-executor.5 Not tainted 5.1.0-rc6 #79 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1571 check_prev_add.constprop.0+0xf11/0x23c0 kernel/locking/lockdep.c:2220 check_prevs_add kernel/locking/lockdep.c:2333 [inline] validate_chain kernel/locking/lockdep.c:2714 [inline] __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072 mutex_lock_killable_nested+0x16/0x20 kernel/locking/mutex.c:1102 do_io_accounting+0x1f4/0x830 fs/proc/base.c:2740 proc_tid_io_accounting+0x20/0x30 fs/proc/base.c:2783 proc_single_show+0xf6/0x170 fs/proc/base.c:744 seq_read+0x4db/0x1130 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:922 vfs_readv+0xf0/0x160 fs/read_write.c:984 do_preadv+0x1c4/0x280 fs/read_write.c:1068 __do_sys_preadv fs/read_write.c:1118 [inline] __se_sys_preadv fs/read_write.c:1113 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1113 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458c29 Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007feb95b47c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458c29 RDX: 2000000000000113 RSI: 0000000020000480 RDI: 0000000000000005 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007feb95b486d4 R13: 00000000004c5969 R14: 00000000004d9cc8 R15: 00000000ffffffff --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.