From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f206.google.com (mail-oi1-f206.google.com [209.85.167.206]) (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 5553540EB81 for ; Tue, 4 Aug 2026 03:17:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785813463; cv=none; b=dm1GLnqrKvKOnfg28NUNbw1W0BtRvlG7aoLXD652sf6+82DD1CKldtEEHE9CApV6F/9ZDC51M9lN4BtI+840qq/X65xICF9dJ9nM880Hl14OIraaWJDYes0j32EZ0T0IUs3m4pyKzosVydWJFxHqwGHrCmnpRawhXrHgZ4qoehc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785813463; c=relaxed/simple; bh=qvQmn7GXQmbqP1KH12N1PKWy4Q0IA30OMH5HSW/bewQ=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=TC61vE/nRdIAJklKHXKSImxXF6vAnOhrurhsTnmMP0zuFELheMSrx3JryHS91CjMhZDwJV4vZGM88TjkjHBax/7ZEQTTNAgC2eafzObYncmOPLrVsp0nPEVlMtT1vDJ3bMDutTz4vofgl3iD9EzacBM1orNqNpASQuZe1Mvl2ns= 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=209.85.167.206 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-f206.google.com with SMTP id 5614622812f47-4a41f46d629so6483748b6e.3 for ; Mon, 03 Aug 2026 20:17:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785813461; x=1786418261; 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=WvbIdHRijZxTDFtSkb6sL8tw/r5AAl0KoJSh/W+ke/w=; b=SohZgy8j2k/kR7SNO79+G7S1Y1DIR55TjU0SVoA+LF/oa1ZDH6U5t233o1Yp1wHLx3 caWIqQe0+G1FrhIS3G50/o8lPqII/JuWAPRa9ku3uXNro8LVOhD0ZmLzsSk7+O4o8115 JF0ABzjN+bazn9WIAwe0iH0GKIuwfIoGapUL93W4ypCDbxY9LP9GGz+rbmwOGBxuV5ME GtbfdteWs+xe2fvpR+/TjjCKHZ9jNeCfQkCXrG4DKjP1Evu3MCKtWgmG8ISsXieFu9C6 QPla5+qWBN6XWbQ2j1twuQ4Na/vk85s3N56PHqphbVMPSPgnnS7wPRyiVIiUHE6pxoWO OgHQ== X-Forwarded-Encrypted: i=1; AHgh+RpSf9Bt7+HAiRSxbKPCSit1lv+S1Fvhvi4XHJ+0HxiaBaeh5YWM+rkQzsmtsNJnCyEiMbrl7Ycp1QNKT7o=@vger.kernel.org X-Gm-Message-State: AOJu0YwzM7KhsEADlXtKzm4BUwVh0APweoOinzpcPfMhsOX0tzmYcV9I hV8frV4w4paQkXnibNqWE/Ojc1MOUko/PhI5NK0DUhVDcRaRkUSRYZSjBI6dssdiW90QIdVpxxU suKPFxqKMhNFPHxgWOVqqdBAKE3jtCaur1TQeypMmjIY6gMQCGcC/Mtqe2IA= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:1c09:b0:496:11f1:f2b3 with SMTP id 5614622812f47-4af5e461595mr20728510b6e.20.1785813461240; Mon, 03 Aug 2026 20:17:41 -0700 (PDT) Date: Mon, 03 Aug 2026 20:17:41 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7159d5.9511d2ce.1fc5b9.0333.GAE@google.com> Subject: [syzbot] [serial?] WARNING in register_console From: syzbot To: gregkh@linuxfoundation.org, jirislaby@kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 075b74841bd0 Linux 7.2-rc6 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16947db9580000 kernel config: https://syzkaller.appspot.com/x/.config?x=cb17729fb04b1e3a dashboard link: https://syzkaller.appspot.com/bug?extid=1ebbc20f223b99446034 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a0f4edd30437/disk-075b7484.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/07bfd5e330f0/vmlinux-075b7484.xz kernel image: https://storage.googleapis.com/syzbot-assets/96d6ea3053f1/bzImage-075b7484.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+1ebbc20f223b99446034@syzkaller.appspotmail.com printk: legacy console [ttyS0] enabled ------------[ cut here ]------------ IS_ERR(kt) WARNING: kernel/printk/printk.c:3728 at legacy_kthread_create kernel/printk/printk.c:3728 [inline], CPU#1: syz.5.580/9206 WARNING: kernel/printk/printk.c:3728 at printk_kthreads_check_locked+0x2a7/0x3f0 kernel/printk/printk.c:3802, CPU#1: syz.5.580/9206 Modules linked in: CPU: 1 UID: 0 PID: 9206 Comm: syz.5.580 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:legacy_kthread_create kernel/printk/printk.c:3728 [inline] RIP: 0010:printk_kthreads_check_locked+0x2a7/0x3f0 kernel/printk/printk.c:3802 Code: fe c1 38 c1 7c 9a 4c 89 f7 e8 f5 89 8a 00 eb 90 e8 be 16 21 00 eb 05 e8 b7 16 21 00 b0 01 88 05 0f a6 08 18 e9 e2 00 00 00 90 <0f> 0b 90 48 c7 c7 80 bd 6d 8b e8 fa a0 82 ff 48 8b 1d 73 a0 04 18 RSP: 0018:ffffc90005367a70 EFLAGS: 00010206 RAX: fffffffffffffffc RBX: 0000000000000001 RCX: 664c2998e3563700 RDX: ffffc90016660000 RSI: 000000000000051b RDI: 000000000000051c RBP: ffffc90005367b70 R08: ffff88803f2dbfaf R09: 1ffff11007e5b7f5 R10: dffffc0000000000 R11: ffffed1007e5b7f6 R12: 0000000000000000 R13: dffffc0000000000 R14: 1ffff92000a6cf5c R15: dffffc0000000000 FS: 00007f51410156c0(0000) GS:ffff888125d3e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb5f0865000 CR3: 0000000040d7c000 CR4: 00000000003526f0 Call Trace: register_console+0xc19/0xfc0 kernel/printk/printk.c:4221 console_store+0x359/0x4f0 drivers/tty/serial/serial_core.c:2999 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5142dde019 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:00007f5141015028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f5143066090 RCX: 00007f5142dde019 RDX: 0000000000000002 RSI: 0000200000000600 RDI: 0000000000000003 RBP: 00007f5142e7500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5143066128 R14: 00007f5143066090 R15: 00007ffe01de2878 --- 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