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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAFA5C77B7F for ; Mon, 8 May 2023 03:43:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231764AbjEHDnV (ORCPT ); Sun, 7 May 2023 23:43:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231301AbjEHDnS (ORCPT ); Sun, 7 May 2023 23:43:18 -0400 Received: from mail-il1-f207.google.com (mail-il1-f207.google.com [209.85.166.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28D1C59D8 for ; Sun, 7 May 2023 20:42:46 -0700 (PDT) Received: by mail-il1-f207.google.com with SMTP id e9e14a558f8ab-32afe238257so27498695ab.3 for ; Sun, 07 May 2023 20:42:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683517365; x=1686109365; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=AD/Uj1Q/goXoaqsQL8mKoMpw3all4e+dW7FDARqYfq4=; b=deS1KjeNIEhepdw7pzFuvQYFfMSAtGPu64ZYpA6NtLiFMAi25E3Jdus3G55bGJXBGX At9kXW7kShoTCXvXaazz3RtsRc/CGYp/d4U7DPTy1WRwLzrsQ8/fgTiuafk+YmE5VXkH jvE3i0VtEi24Xmj8kfmVf7wrL3T32ldyTz95gOrM1dq/hNHwKIRnB60l0pIz6msh0LTg +4Obs7yxjJcAqYfRDqCb/+RrQXIH+x2ungc4LjuXjQd4ux51M6BPO34RqOf/85Uh87Cw nbQdvlg/lrDipCAEidr9R9EscFYjV/ywbn2fher8dX4d5MHb/CKuLUQ8qOUCuNQtroOQ jp+Q== X-Gm-Message-State: AC+VfDz5XR7Hc2orZsg+1Wzjdwx17K90OCnECL+1TE8mKm+A9MK8NoCo qF4FTLBA68CLAHMQx954s5vW54UJPJ4jfneUy6kh8uUgenAZ X-Google-Smtp-Source: ACHHUZ74DD54/wnbAWiVmUxISXDc7bGPfFZmLXF0c1G5UYocjb6eO3+WHWPNBBKT/FKFwgKOhGmGsWExOBU6q8HxQNGTqDwcOXEz MIME-Version: 1.0 X-Received: by 2002:a92:dc45:0:b0:32b:1c9f:3c48 with SMTP id x5-20020a92dc45000000b0032b1c9f3c48mr4933020ilq.1.1683517365516; Sun, 07 May 2023 20:42:45 -0700 (PDT) Date: Sun, 07 May 2023 20:42:45 -0700 In-Reply-To: <000000000000e15c0905f8c5101b@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000008b80c905fb266ec4@google.com> Subject: Re: [syzbot] [ext4?] possible deadlock in ext4_multi_mount_protect From: syzbot To: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org syzbot has found a reproducer for the following issue on: HEAD commit: 14f8db1c0f9a Merge branch 'for-next/core' into for-kernelci git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci console output: https://syzkaller.appspot.com/x/log.txt?x=1168e64c280000 kernel config: https://syzkaller.appspot.com/x/.config?x=a837a8ba7e88bb45 dashboard link: https://syzkaller.appspot.com/bug?extid=6b7df7d5506b32467149 compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: arm64 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=159b92b8280000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14355e4c280000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/ad6ce516eed3/disk-14f8db1c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/1f38c2cc7667/vmlinux-14f8db1c.xz kernel image: https://storage.googleapis.com/syzbot-assets/d795115eee39/Image-14f8db1c.gz.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/36779692cd0c/mount_2.gz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6b7df7d5506b32467149@syzkaller.appspotmail.com EXT4-fs (loop0): 1 truncate cleaned up EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 without journal. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected 6.3.0-rc7-syzkaller-g14f8db1c0f9a #0 Not tainted ------------------------------------------------------ syz-executor258/5925 is trying to acquire lock: ffff0000dba3c460 (sb_writers#3){.+.+}-{0:0}, at: ext4_multi_mount_protect+0x2f8/0x8c8 fs/ext4/mmp.c:343 but task is already holding lock: ffff0000dba3c0e0 (&type->s_umount_key#29){++++}-{3:3}, at: vfs_fsconfig_locked fs/fsopen.c:253 [inline] ffff0000dba3c0e0 (&type->s_umount_key#29){++++}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:439 [inline] ffff0000dba3c0e0 (&type->s_umount_key#29){++++}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline] ffff0000dba3c0e0 (&type->s_umount_key#29){++++}-{3:3}, at: __arm64_sys_fsconfig+0xa14/0xd18 fs/fsopen.c:314 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&type->s_umount_key#29){++++}-{3:3}: down_write+0x50/0xc0 kernel/locking/rwsem.c:1573 __do_sys_quotactl_fd fs/quota/quota.c:997 [inline] __se_sys_quotactl_fd fs/quota/quota.c:972 [inline] __arm64_sys_quotactl_fd+0x2fc/0x4a4 fs/quota/quota.c:972 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 -> #0 (sb_writers#3){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056 lock_acquire+0x238/0x718 kernel/locking/lockdep.c:5669 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1477 [inline] sb_start_write include/linux/fs.h:1552 [inline] write_mmp_block+0xe4/0xb70 fs/ext4/mmp.c:50 ext4_multi_mount_protect+0x2f8/0x8c8 fs/ext4/mmp.c:343 __ext4_remount fs/ext4/super.c:6543 [inline] ext4_reconfigure+0x2180/0x2928 fs/ext4/super.c:6642 reconfigure_super+0x328/0x738 fs/super.c:956 vfs_fsconfig_locked fs/fsopen.c:254 [inline] __do_sys_fsconfig fs/fsopen.c:439 [inline] __se_sys_fsconfig fs/fsopen.c:314 [inline] __arm64_sys_fsconfig+0xa1c/0xd18 fs/fsopen.c:314 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&type->s_umount_key#29); lock(sb_writers#3); lock(&type->s_umount_key#29); lock(sb_writers#3); *** DEADLOCK *** 2 locks held by syz-executor258/5925: #0: ffff0000d5b8a470 (&fc->uapi_mutex){+.+.}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:437 [inline] #0: ffff0000d5b8a470 (&fc->uapi_mutex){+.+.}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline] #0: ffff0000d5b8a470 (&fc->uapi_mutex){+.+.}-{3:3}, at: __arm64_sys_fsconfig+0x720/0xd18 fs/fsopen.c:314 #1: ffff0000dba3c0e0 (&type->s_umount_key#29){++++}-{3:3}, at: vfs_fsconfig_locked fs/fsopen.c:253 [inline] #1: ffff0000dba3c0e0 (&type->s_umount_key#29){++++}-{3:3}, at: __do_sys_fsconfig fs/fsopen.c:439 [inline] #1: ffff0000dba3c0e0 (&type->s_umount_key#29){++++}-{3:3}, at: __se_sys_fsconfig fs/fsopen.c:314 [inline] #1: ffff0000dba3c0e0 (&type->s_umount_key#29){++++}-{3:3}, at: __arm64_sys_fsconfig+0xa14/0xd18 fs/fsopen.c:314 stack backtrace: CPU: 0 PID: 5925 Comm: syz-executor258 Not tainted 6.3.0-rc7-syzkaller-g14f8db1c0f9a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233 show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 dump_stack+0x1c/0x28 lib/dump_stack.c:113 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2056 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3098 [inline] check_prevs_add kernel/locking/lockdep.c:3217 [inline] validate_chain kernel/locking/lockdep.c:3832 [inline] __lock_acquire+0x3338/0x764c kernel/locking/lockdep.c:5056 lock_acquire+0x238/0x718 kernel/locking/lockdep.c:5669 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1477 [inline] sb_start_write include/linux/fs.h:1552 [inline] write_mmp_block+0xe4/0xb70 fs/ext4/mmp.c:50 ext4_multi_mount_protect+0x2f8/0x8c8 fs/ext4/mmp.c:343 __ext4_remount fs/ext4/super.c:6543 [inline] ext4_reconfigure+0x2180/0x2928 fs/ext4/super.c:6642 reconfigure_super+0x328/0x738 fs/super.c:956 vfs_fsconfig_locked fs/fsopen.c:254 [inline] __do_sys_fsconfig fs/fsopen.c:439 [inline] __se_sys_fsconfig fs/fsopen.c:314 [inline] __arm64_sys_fsconfig+0xa1c/0xd18 fs/fsopen.c:314 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2c0 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x64/0x198 arch/arm64/kernel/syscall.c:193 el0_svc+0x4c/0x15c arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 EXT4-fs warning (device loop0): ext4_enable_quotas:7001: Failed to enable quota tracking (type=2, err=-22, ino=15). Please run e2fsck to fix. --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.