From: Andrew Morton <akpm@linux-foundation.org>
To: Jan Kara <jack@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
jslaby@suse.cz
Subject: Re: [PATCH] printk: Avoid softlockups in console_unlock()
Date: Tue, 15 Jan 2013 23:37:42 -0800 [thread overview]
Message-ID: <20130115233742.e8571f92.akpm@linux-foundation.org> (raw)
In-Reply-To: <1358272714-23375-1-git-send-email-jack@suse.cz>
On Tue, 15 Jan 2013 18:58:34 +0100 Jan Kara <jack@suse.cz> wrote:
> A CPU can be caught in console_unlock() for a long time (tens of seconds are
> reported by our customers) when other CPUs are using printk heavily and serial
> console makes printing slow. This triggers softlockup warnings because
> interrupts are disabled for the whole time console_unlock() runs (e.g.
> vprintk() calls console_unlock() with interrupts disabled).
It should trigger the NMI watchdog in that case?
> We fix the issue by printing at most 1 KB of messages (unless we are in an
> early boot stage or oops is happening) in one console_unlock() call. The rest
> of the buffer will be printed either by further callers to printk() or by a
> queued work.
Complex. Did you try just putting a touch_nmi_watchdog() in the loop?
next prev parent reply other threads:[~2013-01-16 7:33 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-15 17:58 [PATCH] printk: Avoid softlockups in console_unlock() Jan Kara
2013-01-16 7:37 ` Andrew Morton [this message]
2013-01-16 10:16 ` Jan Kara
2013-01-16 22:50 ` Andrew Morton
2013-01-16 23:55 ` Jan Kara
2013-01-17 0:11 ` Andrew Morton
2013-01-17 21:04 ` Jan Kara
2013-01-17 21:39 ` Andrew Morton
2013-01-17 23:46 ` Jan Kara
2013-01-17 23:50 ` Andrew Morton
2013-01-21 21:00 ` Jan Kara
2013-01-29 14:54 ` Jan Kara
2013-01-31 0:08 ` Andrew Morton
2013-01-31 12:46 ` Jan Kara
2013-01-31 7:44 ` anish singh
2013-01-31 21:21 ` Andrew Morton
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