Re: kernel hang during reboot when cmdline include a non-exist console device

[James Wang <jnwang@linux.alibaba.com>]

在 2021/8/31 PM4:14, Petr Mladek 写道:
> Adding the reporter into Cc.
>
> On Tue 2021-08-31 12:17:59, Sergey Senozhatsky wrote:
>> On (21/08/30 19:53), Linus Torvalds wrote:
>>> There's a bugzilla for this, but let's just move it to reguilar email,
>>> unless some of you want to track it that way.
>>>
>>> The bugzilla entry says
>>>
>>>    "When reboot， the capslock key of thinkpad x1 starts blinking"
>>>
>>> which sounds like there's an oops that just isn't showing, quite
>>> possibly because the console has already been shut down.
>>>
>>> I didn't test this out, and would sincerely hope that somebody else is
>>> willing to follow up on it since I'm in the busiest part of the merge
>>> window.
>> [..]
>>
>>>> https://bugzilla.kernel.org/show_bug.cgi?id=214201
>> I think normally wrong/empty console boot argument should not cause
>> problems. We have a huge number of devices that use console="", for
>> instance. But on some hardware this triggers panic(), very early on.
>>
>> I have the same symptoms on my laptop, and so far haven't been able
>> to figure out how to track it down, but I need to re-start my investigation.
> Sergey, I think that you talk about the crash where there is no registered
> console and console_on_rootfs() fails to create stdin, stdout, and
> stderr for the init process. As a result the kernel crashes
> during boot.
>
> But the bugreport says that the system booted. It crashed later during
> reboot. It will likely be in the shutdown phase. It still might be still
> be caused by the missing console. But we should rule out other
> problems.
>
> James, do you see the problem:
>
>    1. When there is a real console registered. When you remove the
>       wrong console= parameter.
if I use a real tty, no problem;
>
>    2. When using "reboot -f" so that the system reboots a dirty way
>       without trying to shut down services.

Yes，I have to use "reboot -f" to avoid a cold reboot;

> Best Regards,
> Petr