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From: Steven Rostedt <rostedt@goodmis.org>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>,
	"Petr Mladek" <pmladek@suse.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Lech Perczak" <l.perczak@camlintechnologies.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Krzysztof Drobiński" <k.drobinski@camlintechnologies.com>,
	"Pawel Lenkow" <p.lenkow@camlintechnologies.com>,
	"John Ogness" <john.ogness@linutronix.de>,
	"Tejun Heo" <tj@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>
Subject: Re: Regression in v4.19.106 breaking waking up of readers of /proc/kmsg and /dev/kmsg
Date: Sat, 29 Feb 2020 18:47:19 -0500	[thread overview]
Message-ID: <20200229184719.714dee74@oasis.local.home> (raw)
In-Reply-To: <20200229033253.GA212847@google.com>

On Sat, 29 Feb 2020 12:32:53 +0900
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> wrote:

> > What do folks think?  
> 
> Well, my 5 cents, there is nothing that prevents "too-early"
> printk_deferred() calls in the future. From that POV I'd probably
> prefer to "forbid" printk_deffered() to touch per-CPU deferred
> machinery until it's not "too early" anymore. Similar to what we
> do in printk_safe::queue_flush_work().

I agree that printk_deferred() should handle being called too early.
But the issue is with per_cpu variables correct? Not the irq_work?

We could add a flag in init/main.c after setup_per_cpu_areas() and then
just have printk_deferred() act like a normal printk(). At that point,
there shouldn't be an issue in calling printk() directly, is there?

-- Steve

  parent reply	other threads:[~2020-02-29 23:47 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-27 11:09 Regression in v4.19.106 breaking waking up of readers of /proc/kmsg and /dev/kmsg Lech Perczak
2020-02-27 12:36 ` Greg Kroah-Hartman
2020-02-27 12:39   ` Lech Perczak
2020-02-27 14:08     ` Lech Perczak
2020-02-28  3:13       ` Sergey Senozhatsky
2020-02-28  9:11         ` John Ogness
2020-02-28 12:02           ` Sergey Senozhatsky
2020-02-28 10:04         ` Petr Mladek
2020-02-28 10:58           ` Greg Kroah-Hartman
2020-02-28 11:32             ` Petr Mladek
2020-02-28 11:39               ` Greg Kroah-Hartman
2020-02-28 13:02               ` Petr Mladek
2020-02-28 13:41                 ` Greg Kroah-Hartman
2020-02-28 20:53                 ` Theodore Y. Ts'o
2020-02-29  3:32                   ` Sergey Senozhatsky
2020-02-29  4:08                     ` Sergey Senozhatsky
2020-02-29 23:47                     ` Steven Rostedt [this message]
2020-03-01  5:22                       ` Sergey Senozhatsky
2020-03-02  9:49                         ` Petr Mladek
2020-03-02  9:59                           ` Sergey Senozhatsky
2020-02-28 11:49           ` Sergey Senozhatsky

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