From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f78.google.com (mail-oo1-f78.google.com [209.85.161.78]) (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 EA7D23368A0 for ; Fri, 17 Apr 2026 15:47:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776440853; cv=none; b=PBPMCIcug2lrcWWLTtgvTZa2peNggFnyJAb3v+/RYfXK6OVrJIq3LE66zdoM78CCXEtrwNhRpmZCUze3VaKe1ruyuFBOg3I/Gw2S8QH3bCt71Ppdsao6zB2uV93QIm833v8T1Z3oWr42YXMYIXr8S0dFt1QjHRzHDInKLo6TpBQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776440853; c=relaxed/simple; bh=Nvrxc4jmEEXRGllkTSF9qjZx+a6uDxAOHtMTwgzSbaE=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=EoNs341d32g3Bq4XJn7+EqbPWfoeqBqRe7FyLLtQHPByjCHwWmNh0CJr1F4EJ8A/XQ1XINqyJbhabcDIjBz9oQ+Yh5tFh8Un7eUYY9vuq3mpn7Tc/gkBYWd+RMvYqr3R0927JxIzYDRIaKcLEjP/UL1mheEDZs6AzaSzSeBM/3U= 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=209.85.161.78 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-oo1-f78.google.com with SMTP id 006d021491bc7-69271008251so1628784eaf.2 for ; Fri, 17 Apr 2026 08:47:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776440851; x=1777045651; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=cUt4GZQrLq2oUt8/SIsFIwmSMFLUamz2oX3iNG2Nn20=; b=pdZLrU6jPbzDJSE1ZY+CtWi2D1TNXZrlJneyyi3rYkzAl0xWL60ur7T5D2of3LW/qV 9gWRf/rht0aq2AuX6VJ+CJ3fPzrDF4l8XYq6KL61K5ExFE7XsmDItmwx0aJpo4jDxTx8 G6xvWaMgoyhFp6hS00gKpqysn141RD1/cpGvPxC2P+z5LW9eVdVOP9SQIBl4tkgDDRlf 1wuw7ZqSYxSecT/cSwHMDSlIrFgMZ+tvze4GVTXK6EnC4rKCfn7zTD7nHLC2cJjG2q5d YfIv5yQHN3JXgqHv2hIBEpOYo436jPAwjLXW4xKaZq9TunYLixfX3dqEY0M4iZJ2/7GI dYPw== X-Forwarded-Encrypted: i=1; AFNElJ9f1kXuThtSxK91ERm6EHTAavI8rlBR8wc6VyGuUt8Lm/PXKzINjE8l6Y9yKDmywTc3Ea37Rfrr+5xew9g=@vger.kernel.org X-Gm-Message-State: AOJu0YypRCf8DBuwnToSTa53T9CgXHzyab5NKecoWRxx7nF7jTKXlAc3 7xTQ4uIsWVtIpnwsXEPVU/hXR2BZB+GFxOhvr78n5Fe7zF3gKJhtFHeb47EWMrmV4VFGkGd+6nt 5JcVl4VfExa9a7s/XGl/BCxURY8XUtWJYHanEfWlCPx4JjQDOksQLjVTQp+0= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:221c:b0:683:260d:afc0 with SMTP id 006d021491bc7-69462ee702fmr1672418eaf.35.1776440850914; Fri, 17 Apr 2026 08:47:30 -0700 (PDT) Date: Fri, 17 Apr 2026 08:47:30 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69e25612.a00a0220.1bd0ca.0005.GAE@google.com> Subject: [syzbot] [autofs?] possible deadlock in anon_pipe_write (2) From: syzbot To: autofs@vger.kernel.org, linux-kernel@vger.kernel.org, raven@themaw.net, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 028ef9c96e96 Linux 7.0 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=147210ce580000 kernel config: https://syzkaller.appspot.com/x/.config?x=5a3e5e8c17cc174e dashboard link: https://syzkaller.appspot.com/bug?extid=459d8d87e3c2a46d4102 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/ec3fc4ab21e9/disk-028ef9c9.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/edc0fd5a0fd3/vmlinux-028ef9c9.xz kernel image: https://storage.googleapis.com/syzbot-assets/7c5a57bcdac7/bzImage-028ef9c9.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+459d8d87e3c2a46d4102@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz-executor/5806 is trying to acquire lock: ffff88807ab04868 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x163/0x1d40 fs/pipe.c:458 but task is already holding lock: ffff888033264948 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:55 [inline] ffff888033264948 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sbi->pipe_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:255 autofs_d_automount+0x490/0x950 fs/autofs/root.c:409 follow_automount fs/namei.c:1560 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1613 traverse_mounts fs/namei.c:1642 [inline] handle_mounts fs/namei.c:1744 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2101 step_into fs/namei.c:2149 [inline] walk_component fs/namei.c:2285 [inline] lookup_last fs/namei.c:2786 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2810 filename_lookup+0x202/0x590 fs/namei.c:2839 kern_path+0x37/0x50 fs/namei.c:3046 lookup_bdev+0xd8/0x280 block/bdev.c:1221 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1306 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352 aio_write+0x3ba/0x920 fs/aio.c:1633 __io_submit_one fs/aio.c:2005 [inline] io_submit_one+0x1142/0x1fb0 fs/aio.c:2052 __do_sys_io_submit fs/aio.c:2111 [inline] __se_sys_io_submit fs/aio.c:2081 [inline] __x64_sys_io_submit+0x1b1/0x3a0 fs/aio.c:2081 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&of->mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:343 iter_file_splice_write+0x830/0x10a0 fs/splice.c:736 do_splice_from fs/splice.c:936 [inline] do_splice+0x109c/0x1fd0 fs/splice.c:1349 __do_splice+0x33b/0x370 fs/splice.c:1431 __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __x64_sys_splice+0x187/0x250 fs/splice.c:1616 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&pipe->mutex){+.+.}-{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+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 anon_pipe_write+0x163/0x1d40 fs/pipe.c:458 __kernel_write_iter+0x6b2/0x920 fs/read_write.c:621 __kernel_write+0xf6/0x140 fs/read_write.c:641 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x50d/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:255 autofs_d_automount+0x490/0x950 fs/autofs/root.c:409 follow_automount fs/namei.c:1560 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1613 traverse_mounts fs/namei.c:1642 [inline] handle_mounts fs/namei.c:1744 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2101 step_into fs/namei.c:2149 [inline] open_last_lookups fs/namei.c:4624 [inline] path_openat+0xf95/0x31a0 fs/namei.c:4833 do_file_open+0x20e/0x430 fs/namei.c:4865 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &pipe->mutex --> &of->mutex --> &sbi->pipe_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->pipe_mutex); lock(&of->mutex); lock(&sbi->pipe_mutex); lock(&pipe->mutex); *** DEADLOCK *** 1 lock held by syz-executor/5806: #0: ffff888033264948 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:55 [inline] #0: ffff888033264948 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 stack backtrace: CPU: 0 UID: 0 PID: 5806 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 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 kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x1a2/0x1b90 kernel/locking/mutex.c:776 anon_pipe_write+0x163/0x1d40 fs/pipe.c:458 __kernel_write_iter+0x6b2/0x920 fs/read_write.c:621 __kernel_write+0xf6/0x140 fs/read_write.c:641 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x50d/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:255 autofs_d_automount+0x490/0x950 fs/autofs/root.c:409 follow_automount fs/namei.c:1560 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1613 traverse_mounts fs/namei.c:1642 [inline] handle_mounts fs/namei.c:1744 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2101 step_into fs/namei.c:2149 [inline] open_last_lookups fs/namei.c:4624 [inline] path_openat+0xf95/0x31a0 fs/namei.c:4833 do_file_open+0x20e/0x430 fs/namei.c:4865 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f757039bb3c Code: 4c 89 54 24 18 41 89 f2 41 83 e2 40 75 40 89 f0 f7 d0 a9 00 00 41 00 74 35 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 77 44 48 8b 54 24 18 64 48 2b 14 25 28 00 00 00 RSP: 002b:00007ffe92381580 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f7570432048 RCX: 00007f757039bb3c RDX: 0000000000090800 RSI: 00007ffe92382790 RDI: 00000000ffffff9c RBP: 00007ffe92382790 R08: 00007ffe92383790 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffe92382790 R13: 00007f7570432048 R14: 00000000000d5761 R15: 00007ffe92384950 --- 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