From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f80.google.com (mail-ot1-f80.google.com [209.85.210.80]) (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 A7A0B2E7380 for ; Thu, 6 Aug 2026 00:13:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785975211; cv=none; b=A2pHIuTslVLtkveW6Ke5mXE+//kdNbMbTsikAO67JXeXtk79yyIho4sQ/ieArWHguadrQ4QRAHIIZN2WeIZMQBt1Ts8DoCk8m3m5akGPyO1NIzaQGGCwdm9FVKnia2uXbPtH7lbcJ7x4GoLbLthq5z6bDeGQiRw2S/eFUMsJz70= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785975211; c=relaxed/simple; bh=k5uDvxc8XvzO8I70DCwW8eHW6ro0+GTYHmqic9zVSCI=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=SPdvuNEJ5rZSs00+nl4UEfIWX2R7jpk/Yc/evMnVMp4u6IB2CXtRwWYkHQGJZiKlKyM1V8eRsi7vrUkTCYB5ktxAUe2z6u3+nd70QtevZe62UTcseBTWn3yspvWEfy2QCxRiAxj4WdNgZqaJ7pLREMXawzdXVvJ0Vc9wWSHwpFw= 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=209.85.210.80 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-ot1-f80.google.com with SMTP id 46e09a7af769-7eb641eaf5eso1930004a34.1 for ; Wed, 05 Aug 2026 17:13:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785975208; x=1786580008; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=IuxzatalOz63BgfndC3gH7+t4WCp8R+J+0dGuWkfh7E=; b=NUKldJIb8oZxa4MILZUh+yI+4AoesFXjPAG5mZQ5jkgdF4EIQk5anIM/5bKerqUk7K OzKh4tGPyNVg7AnthyhBCuFZpDScUlgwMROHYGeiyu7NWK4JbeHokkMV37mONPAcsBzf PO7dt8ekIWpkGuL1JLt7uXIt/Eh9q44bNFlz1oSunw5krBsvxD1hyfPd8rX2kwnsU730 m3stzvKvjseaBnqcP+nyH7npVCpy7VtRE05KH3rgl+iGTbmz3/9JxDH2GxbV5Af45AS3 SvHOP29bMHN26TuA2tsXtNWR8FUBu5d4joXRpFRppXUahFWg3a/W2/HDC08T27QqRF4G 4how== X-Forwarded-Encrypted: i=1; AHgh+RoJI8wLEsywrKqOIZWYs8aM+hgIL6MtOEGs6HG8L9PZatGX7z9bSZAi2Oo9A5IRALO8dY960E05GaNlJj8=@vger.kernel.org X-Gm-Message-State: AOJu0YxF0IdJtvultOy2EQpE833QUx2OrWkb8bu1oAZHipHQSMFOsoMv re+JSJDxmlrgU/S2ko039XWprBX7NmcF4mZK6Fydxxn3MKzw3ryL4/iiSkcePW3BB2jdB1WEQ95 J4pMTY+tVfn4ELe3B0EVDMD4ApeWMrl2VpVefmBjLZygwjprx3bAhziL3J2U= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:3089:b0:6ac:ae42:f4d2 with SMTP id 006d021491bc7-6ae96c847e1mr6192030eaf.8.1785975208663; Wed, 05 Aug 2026 17:13:28 -0700 (PDT) Date: Wed, 05 Aug 2026 17:13:28 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a73d1a8.b50370da.49fe0.0009.GAE@google.com> Subject: [syzbot] [autofs?] possible deadlock in autofs_notify_daemon (3) 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: 0131b508c0e2 Merge tag 'ntfs-for-7.2-rc6' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10daee32580000 kernel config: https://syzkaller.appspot.com/x/.config?x=145fa60d73086782 dashboard link: https://syzkaller.appspot.com/bug?extid=2b1c8c58f62458852a54 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/237b6b227f6e/disk-0131b508.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/90a5294c2a5d/vmlinux-0131b508.xz kernel image: https://storage.googleapis.com/syzbot-assets/54d17924c110/bzImage-0131b508.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2b1c8c58f62458852a54@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.4.2436/14866 is trying to acquire lock: ffff8880243be138 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:55 [inline] ffff8880243be138 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 but task is already holding lock: ffff888055e70880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&of->mutex){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336 iter_file_splice_write+0x830/0x10b0 fs/splice.c:736 do_splice_from fs/splice.c:936 [inline] do_splice+0x109c/0x1f90 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+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&pipe->mutex){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 anon_pipe_write+0x25e/0x1d90 fs/pipe.c:553 __kernel_write_iter+0x6bb/0x930 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:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1565 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1618 traverse_mounts fs/namei.c:1647 [inline] handle_mounts fs/namei.c:1749 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2104 step_into fs/namei.c:2152 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2813 filename_lookup+0x202/0x590 fs/namei.c:2842 do_fchownat+0xe6/0x1f0 fs/open.c:800 __do_sys_lchown fs/open.c:829 [inline] __se_sys_lchown fs/open.c:827 [inline] __x64_sys_lchown+0x7e/0xc0 fs/open.c:827 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sbi->pipe_mutex){+.+.}-{4:4}: check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 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:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1565 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1618 traverse_mounts fs/namei.c:1647 [inline] handle_mounts fs/namei.c:1749 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2104 step_into fs/namei.c:2152 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2813 filename_lookup+0x202/0x590 fs/namei.c:2842 kern_path+0x37/0x50 fs/namei.c:3036 lookup_bdev+0xd8/0x280 block/bdev.c:1208 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1278 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 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: &sbi->pipe_mutex --> &pipe->mutex --> &of->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&of->mutex); lock(&pipe->mutex); lock(&of->mutex); lock(&sbi->pipe_mutex); *** DEADLOCK *** 4 locks held by syz.4.2436/14866: #0: ffff888057e055f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259 #1: ffff88807f95c450 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #2: ffff888055e70880 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336 #3: ffff88801f287698 (kn->active#70){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #3: ffff88801f287698 (kn->active#70){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337 stack backtrace: CPU: 0 UID: 0 PID: 14866 Comm: syz.4.2436 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 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+0xeb/0xe60 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 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:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1565 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1618 traverse_mounts fs/namei.c:1647 [inline] handle_mounts fs/namei.c:1749 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2104 step_into fs/namei.c:2152 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2813 filename_lookup+0x202/0x590 fs/namei.c:2842 kern_path+0x37/0x50 fs/namei.c:3036 lookup_bdev+0xd8/0x280 block/bdev.c:1208 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1278 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc8e1d9e019 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc8e2c6a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc8e2026360 RCX: 00007fc8e1d9e019 RDX: 0000000000000012 RSI: 0000200000000040 RDI: 000000000000000c RBP: 00007fc8e1e3500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc8e20263f8 R14: 00007fc8e2026360 R15: 00007ffe9c4403d8 PM: Image not found (code -22) --- 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