From: David Newall <davidn@davidnewall.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Nick Andrew <nick@nick-andrew.net>,
Linas Vepstas <linasvepstas@gmail.com>,
david@lang.hm, Kyle Moffett <kyle@moffetthome.net>,
Ben Goodger <goodgerster@gmail.com>,
Robert Hancock <hancockr@shaw.ca>,
linux-kernel@vger.kernel.org,
"Jeffrey J. Kosowsky" <jeff@kosowsky.org>,
MentalMooMan <slashdot@jameshallam.info>,
Travis Crump <pretzalz@techhouse.org>,
burdell@iruntheinter.net
Subject: Re: Bug: Status/Summary of slashdot leap-second crash on new years 2008-2009
Date: Thu, 08 Jan 2009 01:06:02 +1030 [thread overview]
Message-ID: <4964BDD2.3000803@davidnewall.com> (raw)
In-Reply-To: <20090107141025.143158b7@lxorguk.ukuu.org.uk>
Alan Cox wrote:
>>> The RTC stores the CMOS time in MM DD YY HH:MM:SS format.
>>>
>> Yes, which is perfect for mktime(), which knows about leap seconds and
>> so produces the correct time_t.
>>
>
> mktime in the kernel has no knowledge of leap seconds whatsoever. Go read
> kernel/time.c
>
Is there a mktime() in the kernel? Isn't it pure user-space? Mktime
does appear to know all about leap seconds (assuming they're in zoneinfo.)
>> different understanding. I thought it was said that there's kernel
>> support to handle the leap second flag in NTP's broadcasts, and that
>> that was where the bug was.
>>
>
> All the kernel knows how to do is to slew time (in general) and to repeat
> or remove one second. It has no knowledge of leap seconds and it doesn't
> know how to convert between UTC/TAI/Unix Epoch etc.
I went back to the start of the thread. Chris posted a stack trace
showing "#15 0xffffffff8104ec16 in ntp_leap_second (timer=<value
optimized out>) at kernel/time/ntp.c:143". That would be kernel code to
process leap seconds from NTP broadcasts, I think. That code needs to
be removed.
next prev parent reply other threads:[~2009-01-07 14:36 UTC|newest]
Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-02 19:25 Bug: Status/Summary of slashdot leap-second crash on new years 2008-2009 Linas Vepstas
2009-01-02 20:04 ` Diego Calleja
2009-01-02 20:25 ` Robert Hancock
2009-01-03 6:32 ` David Newall
2009-01-03 6:37 ` Ben Goodger
2009-01-04 8:43 ` David Newall
2009-01-04 9:00 ` Kyle Moffett
2009-01-04 10:03 ` David Newall
2009-01-04 11:13 ` david
2009-01-04 23:15 ` David Newall
2009-01-04 23:25 ` Chris Adams
2009-01-05 0:01 ` David Newall
2009-01-05 0:41 ` Alan Cox
2009-01-05 8:43 ` David Newall
2009-01-05 19:47 ` Alan Cox
2009-01-05 0:29 ` david
2009-01-04 23:37 ` David Newall
2009-01-05 1:05 ` david
2009-01-05 0:14 ` David Newall
2009-01-05 0:21 ` Ben Goodger
2009-01-05 6:34 ` David Newall
2009-01-05 23:03 ` Linas Vepstas
2009-01-05 0:44 ` Alan Cox
2009-01-05 5:48 ` Linas Vepstas
2009-01-05 14:33 ` Nick Andrew
2009-01-05 16:08 ` Linas Vepstas
2009-01-05 17:51 ` david
2009-01-05 17:42 ` Linas Vepstas
2009-01-06 2:27 ` john stultz-lkml
2009-01-06 4:53 ` Linas Vepstas
2009-01-06 5:00 ` Linas Vepstas
2009-01-06 19:40 ` [ntpwg] " M. Warner Losh
2009-01-06 19:50 ` M. Warner Losh
2009-01-07 3:50 ` Danny Mayer
2009-01-07 4:52 ` Linas Vepstas
2009-01-07 10:03 ` David Newall
2009-01-07 17:24 ` M. Warner Losh
2009-01-08 16:51 ` Magnus Danielson
2009-01-07 14:34 ` Danny Mayer
2009-01-07 15:42 ` Linas Vepstas
2009-01-07 19:23 ` Danny Mayer
2009-01-07 16:04 ` john stultz
2009-01-07 17:36 ` M. Warner Losh
2009-01-07 17:39 ` M. Warner Losh
2009-01-07 19:31 ` Alan Cox
2009-01-07 19:42 ` M. Warner Losh
2009-01-08 3:57 ` Danny Mayer
2009-01-08 4:42 ` M. Warner Losh
2009-01-08 10:48 ` Alan Cox
2009-01-08 10:56 ` Alan Cox
2009-01-08 22:22 ` David Mills
2009-01-08 15:02 ` M. Warner Losh
2009-01-08 18:57 ` Marshall Eubanks
2009-01-08 20:09 ` Steve Allen
2009-01-12 16:11 ` Pavel Machek
2009-01-12 17:07 ` [ntpwg] " M. Warner Losh
2009-01-12 21:45 ` Valdis.Kletnieks
2009-01-06 2:31 ` Nick Andrew
2009-01-06 1:59 ` David Newall
2009-01-06 2:18 ` Chris Adams
2009-01-06 2:51 ` Nick Andrew
2009-01-06 9:40 ` Alan Cox
2009-01-07 1:17 ` Nick Andrew
2009-01-07 9:37 ` Alan Cox
2009-01-07 9:46 ` David Newall
2009-01-07 9:54 ` Alan Cox
2009-01-07 10:18 ` David Newall
2009-01-07 10:52 ` Alan Cox
2009-01-07 13:45 ` David Newall
2009-01-07 14:10 ` Alan Cox
2009-01-07 14:36 ` David Newall [this message]
2009-01-07 15:40 ` Alan Cox
2009-01-10 9:46 ` David Newall
2009-01-07 22:13 ` Chris Adams
2009-01-07 13:33 ` Chris Adams
2009-01-07 13:37 ` Alan Cox
2009-01-07 14:12 ` David Newall
2009-01-07 14:09 ` David Newall
2009-01-07 21:42 ` Chris Adams
2009-01-04 11:35 ` Valdis.Kletnieks
2009-01-05 0:08 ` David Newall
2009-01-06 3:53 ` Valdis.Kletnieks
2009-01-04 17:20 ` Kyle Moffett
2009-01-03 7:00 ` Chris Adams
2009-01-04 8:41 ` David Newall
2009-01-02 20:29 ` Linas Vepstas
[not found] ` <8752a8760901021328t545a0327v58faebe1e921680a@mail.gmail.com>
2009-01-02 21:29 ` Ben Goodger
2009-01-03 0:21 ` Chris Adams
2009-01-03 2:23 ` Duane Griffin
2009-01-03 3:45 ` Linas Vepstas
2009-01-03 4:41 ` [PATCH] " Chris Adams
2009-01-03 4:52 ` Duane Griffin
2009-01-03 18:01 ` [PATCH] v2 " Chris Adams
2009-01-03 19:04 ` Duane Griffin
2009-01-03 20:01 ` Linas Vepstas
2009-06-08 2:18 ` Ben Hutchings
2009-06-18 22:34 ` Chris Friesen
2009-06-18 22:58 ` Ben Hutchings
2009-06-18 23:48 ` Chris Friesen
2009-01-06 2:21 ` john stultz-lkml
2009-01-06 2:25 ` Chris Adams
2009-01-06 4:35 ` Linas Vepstas
2009-01-03 3:49 ` Linas Vepstas
2009-01-03 4:02 ` Ben Goodger
2009-01-03 4:46 ` Duane Griffin
2009-01-03 4:50 ` Ben Goodger
2009-01-03 22:58 ` Jeffrey J. Kosowsky
[not found] <fa.dw2l5ZM+UL3xoF6IYh5RLMmbYfw@ifi.uio.no>
[not found] ` <fa.XOM1F85uBvmj4QzZKaDu36nYBk0@ifi.uio.no>
[not found] ` <fa.rviZJBmVqkAE5uxDjhJOpIuKT4g@ifi.uio.no>
[not found] ` <fa.OPVERUiJ763jH2/QynTxgBgoKYw@ifi.uio.no>
[not found] ` <fa.v3FUjJ43bw2G7KiZGaxqL3tD4xo@ifi.uio.no>
[not found] ` <fa.BrNhgY8S+TEOLMiPd27M7YHo9bI@ifi.uio.no>
2009-01-04 16:15 ` Sitsofe Wheeler
2009-01-04 17:26 ` Kyle Moffett
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