From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f207.google.com (mail-oi1-f207.google.com [209.85.167.207]) (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 2F1773C4143 for ; Wed, 17 Jun 2026 21:09:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781730576; cv=none; b=ZEXpTjV5DPhsKzspWvKmiwIeKFBdg0GqbzEKwzHV4gXaL0xlsxejDYQtFuQav+y/eg6Vhof3qDkqbdSO16mjgRjYIcrM6KWJO2aOx0XQEh/02GPRV9QlZSlJ4A1iQDuaDAfHCiLc4orVFFxSW2Bq9fEfW6IwQirOOHoDecfJVP8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781730576; c=relaxed/simple; bh=3+8Brf8ODRXGAjUEM8QFTF95Jb14UFCEEcnSjoqfKiQ=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=Fw+cHTfh0J7yCydEkFBc7JPQePQ05+ZcYYPMMEkCZRxxCUw3rxavPsmzGzW+g8bkt37dvbbuhnty7QIIPB4aIMuwmA1Tne6Wt0wwsC0zXb4SKS6zP54YabmzLpF7FDP9Ae5LUe0gwz+u0YVFsaOBi56QdypJy0JQxex9mEtKheY= 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=209.85.167.207 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-oi1-f207.google.com with SMTP id 5614622812f47-486a24852ddso591963b6e.1 for ; Wed, 17 Jun 2026 14:09:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781730574; x=1782335374; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=Ls6nnt7Gmh5oIq7HUnXiRTpdJiSDl+jtLsjNlkBAIfQ=; b=P+to9dXm8BRG911Go6/bJ76A88Xco4EsPWWsbjbuJSnZugcQGhVwqckZL0kXXWxvgM 08qHJtGzatNdk4yNksssDiZDir4nrW18GOFGscXKEfxkZTDIk+z0lWGg/XMA37ZBYqCv psKvOCNhWJ0I01uen1VCwdunep64Rcc4OFkrdTtImbEI1+sjih9e4SSdSE8QRubMINI9 ovXuPXnxneP2z3tERKVdaNZx3xKOlm+hLgwQSJIgtP3MOfu1F9W3RrGoxzWx8jPZJ+eI 7+MhhWx5mlD753suiZ2w3FC5Dgf3FwUEdCr1rj7dCXHG7jHVQdX2Dzw8zIIFnRPT+d4e N7vw== X-Forwarded-Encrypted: i=1; AFNElJ9rOqWRy6ESXCRUcUmCibKMTrRlQZWE6URC+eN2hXBVOFrpHE6Zae2xcG7gA2V5yEisStv/Y0tBZWJ9Oszj@vger.kernel.org X-Gm-Message-State: AOJu0Yy4/tu697dVcny/oD2eVBp2e4GBzcOcZ8lBq4G+dA0SKA427RbW wbYXstM4Pd1KflKKrJawytWcaF2kE0zbxRCyWM4RAUuSTbSJPybpLQME/RQnccXIq5LIJP4iIiI lZcs/aguUt93Mzpo2MOyqP2l9/91ZbBHkWggrx9/TFGAFJvmTq+Rsw+HopME= Precedence: bulk X-Mailing-List: linux-unionfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:1992:b0:486:a5e9:c320 with SMTP id 5614622812f47-489429ec656mr6608629b6e.29.1781730574114; Wed, 17 Jun 2026 14:09:34 -0700 (PDT) Date: Wed, 17 Jun 2026 14:09:34 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a330d0e.6d5abbec.a50f.0020.GAE@google.com> Subject: [syzbot] [overlayfs?] possible deadlock in ovl_copy_up_start (5) From: syzbot To: amir73il@gmail.com, linux-kernel@vger.kernel.org, linux-unionfs@vger.kernel.org, miklos@szeredi.hu, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 596d152bc5e3 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=10aba8ae580000 kernel config: https://syzkaller.appspot.com/x/.config?x=eb40ba923a822433 dashboard link: https://syzkaller.appspot.com/bug?extid=d4e3aadc5bd19f7e71ff compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 userspace arch: arm64 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/32d15acc8c01/disk-596d152b.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/83b3d8d84761/vmlinux-596d152b.xz kernel image: https://storage.googleapis.com/syzbot-assets/8edfcc3bf911/Image-596d152b.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d4e3aadc5bd19f7e71ff@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.3.611/8517 is trying to acquire lock: ffff0000eee140f8 (&ovl_i_lock_key[depth]){+.+.}-{4:4}, at: ovl_inode_lock_interruptible fs/overlayfs/overlayfs.h:705 [inline] ffff0000eee140f8 (&ovl_i_lock_key[depth]){+.+.}-{4:4}, at: ovl_copy_up_start+0x58/0x264 fs/overlayfs/util.c:735 but task is already holding lock: ffff0000eee13d88 (&ovl_i_mutex_key[depth]/4){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline] ffff0000eee13d88 (&ovl_i_mutex_key[depth]/4){+.+.}-{4:4}, at: lock_two_nondirectories+0xe8/0x148 fs/inode.c:1256 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&ovl_i_mutex_key[depth]/4){+.+.}-{4:4}: __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x178/0x3b0 kernel/locking/lockdep.c:5889 up_write+0x3c/0x5d8 kernel/locking/rwsem.c:1681 inode_unlock include/linux/fs.h:1039 [inline] unlock_two_nondirectories+0x60/0x118 fs/inode.c:1269 ext4_move_extents+0x468/0x3580 fs/ext4/move_extent.c:656 __ext4_ioctl fs/ext4/ioctl.c:1657 [inline] ext4_ioctl+0x2a14/0x4234 fs/ext4/ioctl.c:1922 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #1 (sb_writers#3){.+.+}-{0:0}: percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write include/linux/fs/super.h:125 [inline] ovl_start_write+0xf0/0x324 fs/overlayfs/util.c:32 ovl_do_copy_up fs/overlayfs/copy_up.c:977 [inline] ovl_copy_up_one fs/overlayfs/copy_up.c:1189 [inline] ovl_copy_up_flags+0x980/0x28a4 fs/overlayfs/copy_up.c:1243 ovl_maybe_copy_up+0x108/0x148 fs/overlayfs/copy_up.c:1272 ovl_open+0x12c/0x2c0 fs/overlayfs/file.c:211 do_dentry_open+0x5c4/0xfc8 fs/open.c:947 vfs_open+0x44/0x2d4 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x2234/0x2a6c fs/namei.c:4858 do_file_open+0x1c4/0x2e4 fs/namei.c:4887 do_sys_openat2+0x114/0x1e8 fs/open.c:1364 do_sys_open+0xac/0xdc fs/open.c:1370 __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __arm64_sys_openat+0x9c/0xb8 fs/open.c:1381 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 -> #0 (&ovl_i_lock_key[depth]){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_interruptible_nested+0x24/0x30 kernel/locking/mutex.c:898 ovl_inode_lock_interruptible fs/overlayfs/overlayfs.h:705 [inline] ovl_copy_up_start+0x58/0x264 fs/overlayfs/util.c:735 ovl_copy_up_one fs/overlayfs/copy_up.c:1182 [inline] ovl_copy_up_flags+0x768/0x28a4 fs/overlayfs/copy_up.c:1243 ovl_copy_up+0x24/0x34 fs/overlayfs/copy_up.c:1282 ovl_rename_start fs/overlayfs/dir.c:1176 [inline] ovl_rename+0x2d8/0xfec fs/overlayfs/dir.c:1363 vfs_rename+0xa78/0xd48 fs/namei.c:6064 filename_renameat2+0x66c/0x730 fs/namei.c:6182 __do_sys_renameat2 fs/namei.c:6211 [inline] __se_sys_renameat2 fs/namei.c:6206 [inline] __arm64_sys_renameat2+0xe4/0x114 fs/namei.c:6206 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 other info that might help us debug this: Chain exists of: &ovl_i_lock_key[depth] --> sb_writers#3 --> &ovl_i_mutex_key[depth]/4 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ovl_i_mutex_key[depth]/4); lock(sb_writers#3); lock(&ovl_i_mutex_key[depth]/4); lock(&ovl_i_lock_key[depth]); *** DEADLOCK *** 5 locks held by syz.3.611/8517: #0: ffff00010bddc410 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:493 #1: ffff00010bddc718 (&type->s_vfs_rename_key#3){+.+.}-{4:4}, at: lock_rename fs/namei.c:3791 [inline] #1: ffff00010bddc718 (&type->s_vfs_rename_key#3){+.+.}-{4:4}, at: __start_renaming+0xec/0x33c fs/namei.c:3880 #2: ffff0000eee14300 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline] #2: ffff0000eee14300 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: lock_two_directories+0x19c/0x214 fs/namei.c:3767 #3: ffff0000eee13810 (&ovl_i_mutex_dir_key[depth]/5){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline] #3: ffff0000eee13810 (&ovl_i_mutex_dir_key[depth]/5){+.+.}-{4:4}, at: lock_two_directories+0x1c4/0x214 fs/namei.c:3768 #4: ffff0000eee13d88 (&ovl_i_mutex_key[depth]/4){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline] #4: ffff0000eee13d88 (&ovl_i_mutex_key[depth]/4){+.+.}-{4:4}, at: lock_two_nondirectories+0xe8/0x148 fs/inode.c:1256 stack backtrace: CPU: 1 UID: 0 PID: 8517 Comm: syz.3.611 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x328/0x330 kernel/locking/lockdep.c:2043 check_noncircular+0x158/0x174 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1780/0x2f44 kernel/locking/lockdep.c:5237 lock_acquire+0x140/0x368 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x160/0xef8 kernel/locking/mutex.c:820 mutex_lock_interruptible_nested+0x24/0x30 kernel/locking/mutex.c:898 ovl_inode_lock_interruptible fs/overlayfs/overlayfs.h:705 [inline] ovl_copy_up_start+0x58/0x264 fs/overlayfs/util.c:735 ovl_copy_up_one fs/overlayfs/copy_up.c:1182 [inline] ovl_copy_up_flags+0x768/0x28a4 fs/overlayfs/copy_up.c:1243 ovl_copy_up+0x24/0x34 fs/overlayfs/copy_up.c:1282 ovl_rename_start fs/overlayfs/dir.c:1176 [inline] ovl_rename+0x2d8/0xfec fs/overlayfs/dir.c:1363 vfs_rename+0xa78/0xd48 fs/namei.c:6064 filename_renameat2+0x66c/0x730 fs/namei.c:6182 __do_sys_renameat2 fs/namei.c:6211 [inline] __se_sys_renameat2 fs/namei.c:6206 [inline] __arm64_sys_renameat2+0xe4/0x114 fs/namei.c:6206 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 --- 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