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From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org,
	Lech Perczak <l.perczak@camlintechnologies.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Theodore Ts'o <tytso@mit.edu>,
	John Ogness <john.ogness@linutronix.de>
Subject: Re: [PATCHv2] printk: queue wake_up_klogd irq_work only if per-CPU areas are ready
Date: Thu, 5 Mar 2020 10:30:14 +0900
Message-ID: <20200305013014.GA174444@google.com> (raw)
In-Reply-To: <20200304152159.2p7d7dnztf433i24@pathway.suse.cz>

On (20/03/04 16:21), Petr Mladek wrote:
[..]
> > Fix printk_deferred() and do not queue per-CPU irq_work
> > before per-CPU areas are initialized.
> >
> > [0] https://lore.kernel.org/lkml/aa0732c6-5c4e-8a8b-a1c1-75ebe3dca05b@camlintechnologies.com/
> >
> > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> > Reported-by: Lech Perczak <l.perczak@camlintechnologies.com>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Theodore Ts'o <tytso@mit.edu>
> > Cc: John Ogness <john.ogness@linutronix.de>
>
> Reviewed-by: Petr Mladek <pmladek@suse.com>

Thanks!

> Now, the question is whether to hurry this fix into 5.6 or if
> it could wait for 5.7.
>
> I think that it could wait because 5.6 is not affected by
> the particular printk_deferred(). This patch fixes a long-term
> generic problem. But I am open for other opinions.

Good question. My 5 cents, I would _probably_ push it now. Not
because it fixes any known issues on 5.6, but because we have
a number of LTS kernel (4.19, 4.14, 4.9, 4.4, 3.16) that can be
affected should 1b710b1b10eff9d4 be backported to those kernels.
Which is quite likely, I suspect. The sooner we fix printk_deferred(),
the sooner -stable/LTS picks up the fix, so that we don't have same
regression reports in the future. The regression in question is
pretty hard to track down, git-bisect, perhaps, is the only reasonably
fast way.

	-ss

  reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-03 11:30 Sergey Senozhatsky
2020-03-04 15:21 ` Petr Mladek
2020-03-05  1:30   ` Sergey Senozhatsky [this message]
2020-03-05 18:53     ` Greg Kroah-Hartman
2020-04-09 19:25       ` Simon Kirby
2020-04-10  3:07         ` Sergey Senozhatsky
2020-04-10 23:21           ` Sergey Senozhatsky
2020-04-01 19:34 ` Jann Horn

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