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From: John Stultz <john.stultz@linaro.org>
To: lkml <linux-kernel@vger.kernel.org>
Cc: John Stultz <john.stultz@linaro.org>,
	Prarit Bhargava <prarit@redhat.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Richard Cochran <richardcochran@gmail.com>,
	Jan Kara <jack@suse.cz>, Jiri Bohac <jbohac@suse.cz>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Shuah Khan <shuahkh@osg.samsung.com>
Subject: [RFC][PATCH 3/4] ntp: Use printk_deferred in leapsecond path
Date: Fri, 29 May 2015 13:24:27 -0700	[thread overview]
Message-ID: <1432931068-4980-4-git-send-email-john.stultz@linaro.org> (raw)
In-Reply-To: <1432931068-4980-1-git-send-email-john.stultz@linaro.org>

Looking over the leapsecond code, I noticed the printk messages
reporting the leapsecond insertion in the second_overflow path
were not using the printk_deferred method. This was surprising
since the printk_deferred method was added in part to avoid
printk-ing while holding the timekeeping locks.

See 6d9bcb621b0b (timekeeping: use printk_deferred when holding
timekeeping seqlock) for further rational.

I can only guess that this omission was a git add -p oversight.

Folks particularly worried about leapsecond crashes should
probably pay attention to this patch. Pending review, Its likely
a -stable candidate.

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 kernel/time/ntp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 7a68100..472591e 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -393,7 +393,7 @@ int second_overflow(unsigned long secs)
 		else if (secs % 86400 == 0) {
 			leap = -1;
 			time_state = TIME_OOP;
-			printk(KERN_NOTICE
+			printk_deferred(KERN_NOTICE
 				"Clock: inserting leap second 23:59:60 UTC\n");
 		}
 		break;
@@ -403,7 +403,7 @@ int second_overflow(unsigned long secs)
 		else if ((secs + 1) % 86400 == 0) {
 			leap = 1;
 			time_state = TIME_WAIT;
-			printk(KERN_NOTICE
+			printk_deferred(KERN_NOTICE
 				"Clock: deleting leap second 23:59:59 UTC\n");
 		}
 		break;
-- 
1.9.1


  parent reply	other threads:[~2015-05-29 20:24 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-29 20:24 [RFC][PATCH 0/4] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers John Stultz
2015-05-29 20:24 ` [RFC][PATCH 1/4] selftests: timers: Add leap-second timer edge testing to leap-a-day.c John Stultz
2015-05-29 20:24 ` [RFC][PATCH 2/4] timer_list: Add the base offset so remaining nsecs are accurate for non monotonic timers John Stultz
2015-05-29 20:24 ` John Stultz [this message]
2015-06-02 10:31   ` [RFC][PATCH 3/4] ntp: Use printk_deferred in leapsecond path Jiri Bohac
2015-06-02 10:43     ` Jiri Kosina
2015-06-02 16:14       ` John Stultz
2015-06-02 16:04     ` John Stultz
2015-05-29 20:24 ` [RFC][PATCH 4/4] time: Do leapsecond adjustment in gettime fastpaths John Stultz
2015-05-31 16:05   ` Richard Cochran
2015-06-02  9:01   ` Ingo Molnar
2015-06-02  9:21     ` Peter Zijlstra
2015-06-02 14:09       ` John Stultz
2015-06-02 15:52     ` John Stultz
2015-06-03  9:04       ` Ingo Molnar
2015-06-03 17:44         ` John Stultz
2015-06-04  6:48           ` Ingo Molnar
2015-06-05  0:08             ` John Stultz
2015-06-05  7:29               ` Peter Zijlstra
2015-06-05  9:04                 ` Richard Cochran
2015-06-05  9:10                   ` Peter Zijlstra
2015-06-05 14:12                     ` Richard Cochran
2015-06-05 17:28                       ` John Stultz
2015-06-06  9:44                     ` Thomas Gleixner
2015-06-08 17:55                       ` John Stultz
2015-06-08 19:05                         ` Thomas Gleixner
2015-06-08 20:02                           ` Thomas Gleixner
2015-06-05 11:37                   ` Prarit Bhargava
2015-06-05 12:07                     ` Thomas Gleixner
2015-06-05 14:22                 ` Richard Cochran
2015-06-05 17:24                 ` John Stultz
2015-05-31 13:55 ` [RFC][PATCH 0/4] Fixes for leapsecond expiring early ABS_TIME CLOCK_REALTIME timers Prarit Bhargava
2015-06-01 11:57 ` Prarit Bhargava
2015-06-01 17:02   ` John Stultz
2015-06-01 17:43     ` Prarit Bhargava
2015-06-01 20:18 ` Daniel Bristot de Oliveira
2015-06-01 20:32   ` John Stultz
2015-06-01 21:42   ` Prarit Bhargava
2015-06-01 22:29     ` Daniel Bristot de Oliveira
2015-06-02  6:19       ` John Stultz

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