From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Thomas Gleixner <tglx@linutronix.de>,
Eric Dumazet <edumazet@google.com>,
Dave Jones <davej@codemonkey.org.uk>,
netdev@vger.kernel.org, linux-rt-users@vger.kernel.org,
linux-kernel@vger.kernel.org,
Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Subject: Re: WARN_ON() in netconsole with PREEMPT_RT
Date: Sat, 24 Nov 2018 20:15:45 +0100 [thread overview]
Message-ID: <f479ed5153809ad643cbcf988d76585b@natalenko.name> (raw)
In-Reply-To: <20181111210105.7f376c35@vmware.local.home>
Hi.
On 12.11.2018 03:01, Steven Rostedt wrote:
> On Sun, 11 Nov 2018 21:16:00 +0100
> Oleksandr Natalenko <oleksandr@natalenko.name> wrote:
>> Oh, I see that write_msg() calls netpoll_send_udp() under
>> spin_lock_irqsave(), but in PREEMPT_RT this, AFAIK, does not disable
>> interrupts.
>>
>> So, the real question here is whether the interrupts should be indeed
>> disabled. And if so, -rt should replace spin_lock_irqsave() call there
>> with what? local_irq_save()? and get rid of the warning?
>>
>
> Why do we care if interrupts are disabled with PREEMPT_RT here?
I don't know, if you ask me. But the check was added intentionally with
c9fd56b34efd0, so the author had definitely something on his mind.
Cc'ing him.
> printk() itself has a lot of issues with PREEMPT_RT that we are working
> on dealing with. Right now netconsole is actually at the end of that
> todo list.
OK, I see.
--
Oleksandr Natalenko (post-factum)
next prev parent reply other threads:[~2018-11-24 19:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-11 19:13 WARN_ON() in netconsole with PREEMPT_RT Oleksandr Natalenko
2018-11-11 20:16 ` Oleksandr Natalenko
2018-11-12 2:01 ` Steven Rostedt
2018-11-24 19:15 ` Oleksandr Natalenko [this message]
2018-11-30 18:04 ` Sebastian Andrzej Siewior
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