From: John Ogness <john.ogness@linutronix.de>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>, Nigel Croxon <ncroxon@redhat.com>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
dm-devel@redhat.com, Mikulas Patocka <mpatocka@redhat.com>,
linux-serial@vger.kernel.org
Subject: Re: Serial console is causing system lock-up
Date: Thu, 07 Mar 2019 09:34:37 +0100 [thread overview]
Message-ID: <87pnr3hyle.fsf@linutronix.de> (raw)
In-Reply-To: <20190307082509.GA1925@jagdpanzerIV> (Sergey Senozhatsky's message of "Thu, 7 Mar 2019 17:25:09 +0900")
On 2019-03-07, Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> wrote:
>>> If the serial console is a really slow one and we have a CPU in
>>> atomic context spinnig on prb_lock, while the prb_lock is always
>>> acquired by other CPUs, then it may look like a lock-up scenario.
>>
>> When the console is constantly printing messages, I wouldn't say that
>> looks like a lock-up scenario. It looks like the system is busy
>> printing critical information to the console (which it is).
>
> What if we have N tasks/CPUs calling printk() simultaneously?
Then they take turns printing their messages to the console, spinning
until they get their turn. This still is not and does not look like a
lock-up. But I think you already know this, so I don't understand the
reasoning behind asking the question. Maybe you could clarify what you
are getting at.
John Ogness
next prev parent reply other threads:[~2019-03-07 8:34 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-06 14:27 Serial console is causing system lock-up Mikulas Patocka
2019-03-06 15:22 ` Petr Mladek
2019-03-06 16:07 ` Mikulas Patocka
2019-03-06 16:30 ` Theodore Y. Ts'o
2019-03-06 17:11 ` Mikulas Patocka
2019-03-06 22:19 ` Steven Rostedt
2019-03-06 22:43 ` John Ogness
2019-03-07 2:22 ` Sergey Senozhatsky
2019-03-07 8:17 ` John Ogness
2019-03-07 8:25 ` Sergey Senozhatsky
2019-03-07 8:34 ` John Ogness [this message]
2019-03-07 9:17 ` Sergey Senozhatsky
2019-03-07 10:37 ` John Ogness
2019-03-07 12:26 ` Sergey Senozhatsky
2019-03-07 12:54 ` Mikulas Patocka
2019-03-07 14:21 ` John Ogness
2019-03-07 15:35 ` Petr Mladek
2019-03-12 2:32 ` Sergey Senozhatsky
2019-03-12 8:17 ` John Ogness
2019-03-12 8:59 ` Sergey Senozhatsky
2019-03-12 10:05 ` Mikulas Patocka
2019-03-12 13:19 ` John Ogness
2019-03-12 13:44 ` Petr Mladek
2019-03-12 12:08 ` Petr Mladek
2019-03-12 15:19 ` John Ogness
2019-03-13 2:38 ` Sergey Senozhatsky
2019-03-13 8:43 ` John Ogness
2019-03-14 10:30 ` Sergey Senozhatsky
2019-03-07 14:08 ` John Stoffel
2019-03-07 14:26 ` Mikulas Patocka
2019-03-08 1:22 ` Sergey Senozhatsky
2019-03-08 1:39 ` Sergey Senozhatsky
2019-03-08 2:36 ` John Ogness
2019-03-07 15:16 ` Petr Mladek
2019-03-07 1:56 ` Sergey Senozhatsky
2019-03-07 13:12 ` Mikulas Patocka
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