From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f77.google.com (mail-io1-f77.google.com [209.85.166.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B15D32ED2F for ; Thu, 13 Nov 2025 08:08:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763021312; cv=none; b=YJkHmOuEWyDoG6F4J51OrWtAU0WE/CNMzTUVscoqCzzyOHswErTTty4KCakZ2Dxij5Fx8rdFjFFS/GxUDEdGEALNUGu5fApizVOtIccVzTBdmv/wYKYfzerT7a+dMlg+zokcFNV7vbCkqAVetNOdfc4D18jOBkGluugcZPmnZTU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763021312; c=relaxed/simple; bh=Bz7ED0HRek/uFNG4OY3n7adGXWxkDoF4osrRKhk/0Ec=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=fNoyd0dHqCYgsDhJP+WJl8VglkPHBICeRLI+fF0OqQWcfDWkxVbHcEvC6aCqxjSo+/LOI/9mNXpQu9VqokRHqX7YQOn6NZFF4y6n52LJvcvBXdIjn2EAbvLD/aRyWs1APPqTC3UhvfDxSbEv3rdpCzDrdtdNcxw8jvuRALUWDTg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.166.77 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-io1-f77.google.com with SMTP id ca18e2360f4ac-948cc59142aso68650939f.1 for ; Thu, 13 Nov 2025 00:08:30 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763021309; x=1763626109; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=BjNZP2aelH/P8mQTZ4oGC1U8Z+2onZLGOSHmsIRyDhQ=; b=mmXMDYURq0DsvuZWpYJitRPynnwxpesd2ZAHsn/ULhN80Bb69wJpaYxWD8JjeKXStR roXAp4fItdOJsXKsQ0daxv5RyEBjkX68xbxk6IKABdWkHMcL7b4LNCsSKu5fdFpZyvBm zx/i5gxCk+s8tAuLTsUKP0ea2VzC558Ei182r4huoFcduwELBovV7ooZIxH4X55y+lMi AH8a4aEm7/922gEba0bHU0a7pEqzY9Ak7GyYe7PXv415mwYDlqStyAbVdoLO8C+crQPq YtMBoBU5Rze9LxUZnzxN/Lr8YsLtyNx6/Z2Hn4GXmcfea3hkk9EW6vr4XU3zHdshElAo 41kQ== X-Forwarded-Encrypted: i=1; AJvYcCVF69bmR98GuIDIJU1xBMH54+iJxv/cgbYRewQuLD7T8b/HYKDZcXJphqKFxhl/fyEuMQzkZJbGGGlb@vger.kernel.org X-Gm-Message-State: AOJu0YygFDOmmdvD7Gr4d9blHa7XlJyM5oPkf81hxr15SRLyf0VxZolq ZHwutcAF/l5XLgJlG58Fn+eZJkRSCeeRZrZafI6T+t7e6eU/b+Nqjg/Rn1BwMMI9X1HsrEEtH3N F0atwWmzeyaZJLsiyir4Sg+6PF82yGfD9PKgceH4dQPwaXpHdMcKBMTvGL6o= X-Google-Smtp-Source: AGHT+IE29TSkLF8mS0JVq4UWcSB07f3gfFPFuooM8qL9F5Vk9Szqj22GVIAT0bvZHd7X0SLwsgQil5zYSxaGV74lQSC6iRHu1x0Q Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:5c6:b0:433:7ad4:7392 with SMTP id e9e14a558f8ab-43473d17daemr55243155ab.1.1763021309351; Thu, 13 Nov 2025 00:08:29 -0800 (PST) Date: Thu, 13 Nov 2025 00:08:29 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <691591fd.a70a0220.3124cb.0020.GAE@google.com> Subject: [syzbot] [ext4?] possible deadlock in ext4_xattr_set_handle (7) From: syzbot To: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tytso@mit.edu Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 7bb4d6512545 Merge tag 'v6.18rc4-SMB-client-fixes' of git:.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=170350b4580000 kernel config: https://syzkaller.appspot.com/x/.config?x=e46b8a1c645465a9 dashboard link: https://syzkaller.appspot.com/bug?extid=f0b58a1f5075a90dd9a5 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/ad654d5866e3/disk-7bb4d651.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/7ad4d94f39b6/vmlinux-7bb4d651.xz kernel image: https://storage.googleapis.com/syzbot-assets/1fa5516b633d/bzImage-7bb4d651.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f0b58a1f5075a90dd9a5@syzkaller.appspotmail.com EXT4-fs (loop8): mounted filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09 r/w without journal. Quota mode: none. ext4 filesystem being mounted at /81/mnt supports timestamps until 2038-01-19 (0x7fffffff) fscrypt: AES-256-XTS using implementation "xts-aes-vaes-avx2" ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.8.1928/14101 is trying to acquire lock: ffff8880494b9d78 (&ei->xattr_sem){++++}-{4:4}, at: ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ffff8880494b9d78 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2367 but task is already holding lock: ffff888031d78b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_write fs/ext4/ext4.h:1808 [inline] ffff888031d78b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x2f3/0x1010 fs/ext4/migrate.c:438 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sbi->s_writepages_rwsem){++++}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 percpu_down_read_internal+0x48/0x1c0 include/linux/percpu-rwsem.h:53 percpu_down_read include/linux/percpu-rwsem.h:77 [inline] ext4_writepages_down_read fs/ext4/ext4.h:1796 [inline] ext4_writepages+0x1cc/0x350 fs/ext4/inode.c:3024 do_writepages+0x32e/0x550 mm/page-writeback.c:2604 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1719 writeback_single_inode+0x1f9/0x6a0 fs/fs-writeback.c:1840 write_inode_now+0x160/0x1d0 fs/fs-writeback.c:2903 iput_final fs/inode.c:1901 [inline] iput+0x830/0xc50 fs/inode.c:1966 ext4_xattr_block_set+0x1fce/0x2ac0 fs/ext4/xattr.c:2199 ext4_xattr_move_to_block fs/ext4/xattr.c:2664 [inline] ext4_xattr_make_inode_space fs/ext4/xattr.c:2739 [inline] ext4_expand_extra_isize_ea+0x12da/0x1ea0 fs/ext4/xattr.c:2827 __ext4_expand_extra_isize+0x30d/0x400 fs/ext4/inode.c:6364 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6407 [inline] __ext4_mark_inode_dirty+0x46c/0x700 fs/ext4/inode.c:6485 ext4_evict_inode+0x80d/0xee0 fs/ext4/inode.c:254 evict+0x504/0x9c0 fs/inode.c:810 ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:470 __ext4_fill_super fs/ext4/super.c:5617 [inline] ext4_fill_super+0x5920/0x61e0 fs/ext4/super.c:5736 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 vfs_get_tree+0x92/0x2b0 fs/super.c:1751 fc_mount fs/namespace.c:1208 [inline] do_new_mount_fc fs/namespace.c:3651 [inline] do_new_mount+0x302/0xa10 fs/namespace.c:3727 do_mount fs/namespace.c:4050 [inline] __do_sys_mount fs/namespace.c:4238 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4215 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&ei->xattr_sem){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2367 ext4_set_context+0x21b/0x550 fs/ext4/crypto.c:166 fscrypt_set_context+0x38a/0x460 fs/crypto/policy.c:791 __ext4_new_inode+0x3143/0x3cb0 fs/ext4/ialloc.c:1315 ext4_ext_migrate+0x69f/0x1010 fs/ext4/migrate.c:456 ext4_ioctl_setflags fs/ext4/ioctl.c:705 [inline] ext4_fileattr_set+0xeaf/0x1630 fs/ext4/ioctl.c:1024 vfs_fileattr_set+0x932/0xb90 fs/file_attr.c:298 ioctl_setflags+0x180/0x1e0 fs/file_attr.c:334 do_vfs_ioctl+0x8ed/0x1430 fs/ioctl.c:560 __do_sys_ioctl fs/ioctl.c:595 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); lock(&sbi->s_writepages_rwsem); lock(&ei->xattr_sem); *** DEADLOCK *** 3 locks held by syz.8.1928/14101: #0: ffff888031d7e420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write_file+0x60/0x200 fs/namespace.c:552 #1: ffff8880494bd9f0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline] #1: ffff8880494bd9f0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_fileattr_set+0x14e/0xb90 fs/file_attr.c:278 #2: ffff888031d78b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_writepages_down_write fs/ext4/ext4.h:1808 [inline] #2: ffff888031d78b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: ext4_ext_migrate+0x2f3/0x1010 fs/ext4/migrate.c:438 stack backtrace: CPU: 0 UID: 0 PID: 14101 Comm: syz.8.1928 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 ext4_write_lock_xattr fs/ext4/xattr.h:157 [inline] ext4_xattr_set_handle+0x165/0x1590 fs/ext4/xattr.c:2367 ext4_set_context+0x21b/0x550 fs/ext4/crypto.c:166 fscrypt_set_context+0x38a/0x460 fs/crypto/policy.c:791 __ext4_new_inode+0x3143/0x3cb0 fs/ext4/ialloc.c:1315 ext4_ext_migrate+0x69f/0x1010 fs/ext4/migrate.c:456 ext4_ioctl_setflags fs/ext4/ioctl.c:705 [inline] ext4_fileattr_set+0xeaf/0x1630 fs/ext4/ioctl.c:1024 vfs_fileattr_set+0x932/0xb90 fs/file_attr.c:298 ioctl_setflags+0x180/0x1e0 fs/file_attr.c:334 do_vfs_ioctl+0x8ed/0x1430 fs/ioctl.c:560 __do_sys_ioctl fs/ioctl.c:595 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1f39f8f6c9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1f3ade0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1f3a1e5fa0 RCX: 00007f1f39f8f6c9 RDX: 0000200000000080 RSI: 0000000040086602 RDI: 0000000000000004 RBP: 00007f1f3a011f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1f3a1e6038 R14: 00007f1f3a1e5fa0 R15: 00007fffb7f49f38 EXT4-fs error (device loop8): ext4_validate_block_bitmap:423: comm syz.8.1928: bg 0: bad block bitmap checksum --- This report 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 issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup