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 80E993A6411 for ; Wed, 1 Jul 2026 22:14:29 +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=1782944071; cv=none; b=hWnltCfU0DURXh+vZUGj4xwSZiDJN8VknC1XgNa39qxg582ShRohPSo0DqvsCLxQm+ctBCrTBV9sLyIaUkhhdNUC/Z8E80JLL3sqPu5vV6t5Z5qfho/wgnCpl1AWHx2bVcJuId2PoTTR4t2cjxvK7Qx7oH9DLrbzdlmiOw8yDdE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782944071; c=relaxed/simple; bh=B/q3ofjc+ewEbaVuocOfYgH/++bTBzpnZtdjFBRmvjM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=W1aV3/YSybQcfx/lOFT6epNAa3Vn2OabspmoWHvKIAyMwsLv6gIVx5BKG2+Pw/1AEoQsMKoYQ77vqJldpBIhKmOlUutHvB9bDSF4EUfV355sL4T9QmVAykIsBkGo3eMMpIg6bHPLdsjrWU1OiXj8jbmx2Axv313dLhuC9ATaT54= 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 5614622812f47-485ebc5706cso3363162b6e.0 for ; Wed, 01 Jul 2026 15:14:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782944069; x=1783548869; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=vZRDD+ONulzvza/JukB6r80Nw/G7QQh5U98Wv22NpOA=; b=IgLjreoklaimrrYfBeOmA9WdCL6zeBXbRqAIeprsS+i0TmQZdlWQR+XLoLoc711kXN FEYrqdo38YCBew63A5BMeCgNNNmyTi1dR/hLUJQX79Gk7FnMn1Nq3cShiN2Fo/9vbmpw XUpNE9ZKPfqsOUp06TX4CgbSiPG5ilIAUCAqFTI87dDu2spWohwu1gr+7r6hIS64cqrA 3bzVhu8boC4NrWMclghzkxuwC41msM75zlNZSax3w4BhpKtHGy6Evn7hJeLUXcq37zs/ obD238NbmiilfXgnwuxl45SFEru83ZPlu7ZiYgO4ksTkkBYJruYDsn6lNIS/nDyjzJ2k YZ/A== X-Forwarded-Encrypted: i=1; AFNElJ+mvXh8D59tLAJxhLg/5oDfY5QKleWHqPKoe2xoGP3C8kdaikZekQ5W6XD5lUn4PU0CIB5Aiz1FwwhHptw=@vger.kernel.org X-Gm-Message-State: AOJu0YwKhN+398gguE46K8NO1SPX2dowVHAbNWYyU4s92uaJ04ywHZF9 YdDzjkoPUY73UiIjrZqGoYwSog7RD514+OlT4euxXIjJtpsaF+lfU8+1rkALpYGI4u3DWzRutH8 8SPQOrqZuHd3Jby9sbUdYrWt1C31E9tcXKWo+J+IJ2l5Cgoy8u+22ELOrKAM= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:1801:b0:495:f0ac:8297 with SMTP id 5614622812f47-495f5318f3fmr4773045b6e.33.1782944069214; Wed, 01 Jul 2026 15:14:29 -0700 (PDT) Date: Wed, 01 Jul 2026 15:14:29 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a459145.52c20a74.1f8b39.0005.GAE@google.com> Subject: [syzbot] [comedi?] possible deadlock in comedi_do_insn (2) From: syzbot To: abbotti@mev.co.uk, hsweeten@visionengravers.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 780d569e6c4b Merge tag 'pwm/for-7.2-rc1-2' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=131b4176580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f9bf5d2bfae96234 dashboard link: https://syzkaller.appspot.com/bug?extid=acd959f649966559199c 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 (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-780d569e.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/944d8beefedc/vmlinux-780d569e.xz kernel image: https://storage.googleapis.com/syzbot-assets/615f6b8a2abd/bzImage-780d569e.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+acd959f649966559199c@syzkaller.appspotmail.com ============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.4.6324/17474 is trying to acquire lock: ffff88803435a0f0 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_do_insn+0x2e/0x360 drivers/comedi/kcomedilib/kcomedilib_main.c:183 but task is already holding lock: ffff88803435c8f0 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_unlocked_ioctl+0x180/0x3310 drivers/comedi/comedi_fops.c:2290 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&dev->mutex#4); lock(&dev->mutex#4); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by syz.4.6324/17474: #0: ffff88803435c8f0 (&dev->mutex#4){+.+.}-{4:4}, at: comedi_unlocked_ioctl+0x180/0x3310 drivers/comedi/comedi_fops.c:2290 stack backtrace: CPU: 2 UID: 0 PID: 17474 Comm: syz.4.6324 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_deadlock_bug.cold+0xbd/0xca kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain kernel/locking/lockdep.c:3895 [inline] __lock_acquire+0x1256/0x1a40 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 comedi_do_insn+0x2e/0x360 drivers/comedi/kcomedilib/kcomedilib_main.c:183 comedi_dio_bitfield2+0x3c0/0x420 drivers/comedi/kcomedilib/kcomedilib_main.c:314 bonding_dio_insn_bits+0x2b9/0x570 drivers/comedi/drivers/comedi_bond.c:100 insn_rw_emulate_bits+0x2a2/0x5e0 drivers/comedi/drivers.c:703 parse_insn+0x83f/0x19f0 drivers/comedi/comedi_fops.c:1565 do_insn_ioctl+0x152/0x4e0 drivers/comedi/comedi_fops.c:1790 comedi_unlocked_ioctl+0xf68/0x3310 drivers/comedi/comedi_fops.c:2422 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 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: 0033:0x7f9a0d59ce59 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:00007f9a0e40e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f9a0d815fa0 RCX: 00007f9a0d59ce59 RDX: 0000200000000000 RSI: 000000008028640c RDI: 0000000000000003 RBP: 00007f9a0d632e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9a0d816038 R14: 00007f9a0d815fa0 R15: 00007fff138218d8 --- 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