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Subject: Re: [PATCH -next] panic: complete the flush of the hard deadlock log
 messages to the serial port
To:     Andrew Morton <akpm@linux-foundation.org>
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References: <20201123131359.34600-1-xuqiang36@huawei.com>
 <20201123115235.74aab2449ac5cf27f10a4cfd@linux-foundation.org>
From:   "xuqiang (M)" <xuqiang36@huawei.com>
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Date:   Tue, 24 Nov 2020 11:22:11 +0800
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在 2020/11/24 3:52, Andrew Morton 写道:
> On Mon, 23 Nov 2020 13:13:59 +0000 Xu Qiang <xuqiang36@huawei.com> wrote:
>
>> when hardlockup_all_cpu_backtrace is on, and there are
>> a large number of cores in the system, it takes
>> a long time to output the hard deadlock logs of all cores
>> to the serial port. When the console_flush_on_panic function
>> in panic is executed, console_locked is still held.
>> As a result, garbled characters are displayed in the serial port log.
>>
>> To solve this problem, wait for a maximum of 10s for the serial port
>> to be released before console_flush_on_panic.
> Wouldn't it be better to wait until all the printing of all those
> backtraces has completed?
>
>
> .

The fear that there may be some unexpected abnormal situation,

resulting in the serial port has been occupied without release.


Thanks

         Xu.