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 9CE73C3DA7C for ; Thu, 29 Dec 2022 01:24:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231199AbiL2BX2 (ORCPT ); Wed, 28 Dec 2022 20:23:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229716AbiL2BXY (ORCPT ); Wed, 28 Dec 2022 20:23:24 -0500 Received: from mail-il1-f199.google.com (mail-il1-f199.google.com [209.85.166.199]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51FD713F80 for ; Wed, 28 Dec 2022 17:23:23 -0800 (PST) Received: by mail-il1-f199.google.com with SMTP id a13-20020a056e0208ad00b003034c36b8b5so10973719ilt.9 for ; Wed, 28 Dec 2022 17:23:23 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=eeJLsnPHPnTdoII+fk4/DB6TZ+ww6Hs/SN0JpWJO4S8=; b=HolCuuqJ6PGHDYIKHPTNswLfMlvlsSoahZnEhC8THnjCQ3YdLE/Qo7U7TX+F19NBr3 U8r4n+8BOl8ulgeoEyamuAppQljGo95GX9zcr/pkjcHi96Hx1O2ohiGohROb8/qr+UkT SA/fIqAB0sOwjGT7c2ky9hM+Kg1HpZP0BBcZ498hjArXk3rLTT/jRHH4js0AaBNTHczq +FcHJP/7C7YlJ30slBkWoNGyoFV17XmHjK5/026OF9X4tlCK2u9IH8I9krgwoFjXZ5Ax 1jYfB7HCwAAd18seCdXqpzTUMErshaGHCLyCtudhAj/BxDktKVqKD1xb/mFTqEWscLKG A5Cw== X-Gm-Message-State: AFqh2krl+Gq0DQki2GcG3PLnm9sGpAEYxnT3aPxFwKkAk9WcBQoAHVtx d5GX3fHE/mFqK5Er+NZOQ2Y0eQ4+l6ZYcadPYSdMe34+kZ3U X-Google-Smtp-Source: AMrXdXsohTMDZ+IMtekOV3KljYZi/ZPObBKromXUuAQVIARbMjkM0pmO3zxqW7NnZRfx4FrWwnhn4MUOrF3KWRoCG4Y+wfemZjCC MIME-Version: 1.0 X-Received: by 2002:a02:c64a:0:b0:38a:c06e:daa5 with SMTP id k10-20020a02c64a000000b0038ac06edaa5mr2339690jan.238.1672277002674; Wed, 28 Dec 2022 17:23:22 -0800 (PST) Date: Wed, 28 Dec 2022 17:23:22 -0800 In-Reply-To: <20221229005540.2777-1-hdanton@sina.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000b5e7b405f0ed54fb@google.com> Subject: Re: [syzbot] [ext4?] possible deadlock in ext4_find_inline_entry From: syzbot To: hdanton@sina.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: possible deadlock in ext4_xattr_set_entry EXT4-fs: Warning: mounting with an experimental mount option 'dioread_nolock' for blocksize < PAGE_SIZE EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none. ====================================================== WARNING: possible circular locking dependency detected 6.1.0-rc8-syzkaller-00172-ga5541c0811a0-dirty #0 Not tainted ------------------------------------------------------ syz-executor.0/3668 is trying to acquire lock: ffff0000cf16bd60 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline] ffff0000cf16bd60 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_xattr_inode_create fs/ext4/xattr.c:1453 [inline] ffff0000cf16bd60 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1536 [inline] ffff0000cf16bd60 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_xattr_set_entry+0xdbc/0xe00 fs/ext4/xattr.c:1664 but task is already holding lock: ffff0000cf16b098 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline] ffff0000cf16b098 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0xd0/0x9a0 fs/ext4/xattr.c:2308 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&ei->xattr_sem){++++}-{3:3}: down_read+0x5c/0x78 kernel/locking/rwsem.c:1509 ext4_xattr_get+0x90/0x418 fs/ext4/xattr.c:665 ext4_xattr_security_get+0x40/0x54 fs/ext4/xattr_security.c:20 __vfs_getxattr+0x1fc/0x20c fs/xattr.c:407 cap_inode_need_killpriv+0x34/0x5c security/commoncap.c:301 security_inode_need_killpriv+0x34/0x88 security/security.c:1422 dentry_needs_remove_privs fs/inode.c:1995 [inline] __file_remove_privs+0xe0/0x308 fs/inode.c:2026 file_modified_flags+0x60/0x330 fs/inode.c:2148 file_modified+0x24/0x34 fs/inode.c:2177 ext4_write_checks fs/ext4/file.c:264 [inline] ext4_buffered_write_iter+0x12c/0x294 fs/ext4/file.c:280 ext4_file_write_iter+0x84/0x408 fs/ext4/file.c:700 call_write_iter include/linux/fs.h:2199 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x2dc/0x46c fs/read_write.c:584 ksys_write+0xb4/0x160 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __arm64_sys_write+0x24/0x34 fs/read_write.c:646 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197 el0_svc+0x58/0x150 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:584 -> #0 (&sb->s_type->i_mutex_key#8){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x1530/0x3084 kernel/locking/lockdep.c:5055 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668 down_write+0x5c/0x88 kernel/locking/rwsem.c:1562 inode_lock include/linux/fs.h:756 [inline] ext4_xattr_inode_create fs/ext4/xattr.c:1453 [inline] ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1536 [inline] ext4_xattr_set_entry+0xdbc/0xe00 fs/ext4/xattr.c:1664 ext4_xattr_ibody_set+0x94/0x184 fs/ext4/xattr.c:2224 ext4_xattr_set_handle+0x648/0x9a0 fs/ext4/xattr.c:2381 ext4_xattr_set+0x100/0x1d0 fs/ext4/xattr.c:2495 ext4_xattr_trusted_set+0x4c/0x64 fs/ext4/xattr_trusted.c:38 __vfs_setxattr+0x250/0x260 fs/xattr.c:182 __vfs_setxattr_noperm+0xcc/0x320 fs/xattr.c:216 __vfs_setxattr_locked+0x16c/0x194 fs/xattr.c:277 vfs_setxattr+0xf4/0x1f4 fs/xattr.c:309 do_setxattr fs/xattr.c:594 [inline] setxattr fs/xattr.c:617 [inline] path_setxattr+0x354/0x414 fs/xattr.c:636 __do_sys_lsetxattr fs/xattr.c:659 [inline] __se_sys_lsetxattr fs/xattr.c:655 [inline] __arm64_sys_lsetxattr+0x2c/0x40 fs/xattr.c:655 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197 el0_svc+0x58/0x150 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:584 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->xattr_sem); lock(&sb->s_type->i_mutex_key#8); lock(&ei->xattr_sem); lock(&sb->s_type->i_mutex_key#8); *** DEADLOCK *** 3 locks held by syz-executor.0/3668: #0: ffff0000c9dee460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x20/0x64 fs/namespace.c:393 #1: ffff0000cf16b3d0 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline] #1: ffff0000cf16b3d0 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: vfs_setxattr+0xd4/0x1f4 fs/xattr.c:308 #2: ffff0000cf16b098 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline] #2: ffff0000cf16b098 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0xd0/0x9a0 fs/ext4/xattr.c:2308 stack backtrace: CPU: 1 PID: 3668 Comm: syz-executor.0 Not tainted 6.1.0-rc8-syzkaller-00172-ga5541c0811a0-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call trace: dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:163 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106 dump_stack+0x1c/0x58 lib/dump_stack.c:113 print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2055 check_noncircular+0x14c/0x154 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x1530/0x3084 kernel/locking/lockdep.c:5055 lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5668 down_write+0x5c/0x88 kernel/locking/rwsem.c:1562 inode_lock include/linux/fs.h:756 [inline] ext4_xattr_inode_create fs/ext4/xattr.c:1453 [inline] ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1536 [inline] ext4_xattr_set_entry+0xdbc/0xe00 fs/ext4/xattr.c:1664 ext4_xattr_ibody_set+0x94/0x184 fs/ext4/xattr.c:2224 ext4_xattr_set_handle+0x648/0x9a0 fs/ext4/xattr.c:2381 ext4_xattr_set+0x100/0x1d0 fs/ext4/xattr.c:2495 ext4_xattr_trusted_set+0x4c/0x64 fs/ext4/xattr_trusted.c:38 __vfs_setxattr+0x250/0x260 fs/xattr.c:182 __vfs_setxattr_noperm+0xcc/0x320 fs/xattr.c:216 __vfs_setxattr_locked+0x16c/0x194 fs/xattr.c:277 vfs_setxattr+0xf4/0x1f4 fs/xattr.c:309 do_setxattr fs/xattr.c:594 [inline] setxattr fs/xattr.c:617 [inline] path_setxattr+0x354/0x414 fs/xattr.c:636 __do_sys_lsetxattr fs/xattr.c:659 [inline] __se_sys_lsetxattr fs/xattr.c:655 [inline] __arm64_sys_lsetxattr+0x2c/0x40 fs/xattr.c:655 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall arch/arm64/kernel/syscall.c:52 [inline] el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x48/0x140 arch/arm64/kernel/syscall.c:197 el0_svc+0x58/0x150 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:584 Tested on: commit: a5541c08 Merge branch 'for-next/core' into for-kernelci git tree: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=16f5d4bc480000 kernel config: https://syzkaller.appspot.com/x/.config?x=cbd4e584773e9397 dashboard link: https://syzkaller.appspot.com/bug?extid=d3bb749184481f92deb5 compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: arm64 patch: https://syzkaller.appspot.com/x/patch.diff?x=15be6de4480000