Messages in this thread | | | Subject | Re: [PATCH -stable] ntp: Correct TAI offset during leap second | From | Ben Hutchings <> | Date | Sun, 01 Jul 2012 02:28:18 +0100 |
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On Mon, 2012-06-18 at 14:55 +0100, Ben Hutchings wrote: > On Sun, 2012-06-17 at 19:34 +0200, Richard Cochran wrote: > > On Sun, Jun 17, 2012 at 11:47:51AM -0500, Jonathan Nieder wrote: > > > Ben Hutchings wrote: > > > > On Fri, 2012-06-15 at 11:56 -0700, John Stultz wrote: > > > > > > >> commit dd48d708ff3e917f6d6b6c2b696c3f18c019feed upstream. > > > [...] > > > > This doesn't apply to 3.2.y, unsurprisingly. Let me know if there are > > > > any urgent leap second fixes that will be needed there. > > > > > > 6b43ae8a619d (ntp: Fix leap-second hrtimer livelock) sounds important, > > > but the patch depends on bd3312681f69 (ntp: Add ntp_lock to replace > > > xtime_locking) which does not have a commit message explaining its > > > purpose (and that patch in turn depends on ea7cf49a7633). > > If I understand the commit message for 6b43ae8a619d correctly, the > livelock results from ntp_lock and xtime_lock being acquired in opposite > orders in two threads. Which means it wasn't possible before ntp_lock > was introduced in bd3312681f69. [...]
Apparently some other livelock was possible, though I was unable to reproduce it myself. Some proportion of systems running 2.6.32 or 3.2 (not sure about the intermediate stable-supported versions) are reported to have locked up, either in adjtimex or during the leap second.
I understand that we might not have so long to wait for the next leap second, so if anyone understands what fixes are still needed in stable updates I would really appreciate that.
Ben.
-- Ben Hutchings If you seem to know what you are doing, you'll be given more to do. [unhandled content-type:application/pgp-signature] | |