Hi John, On Tue, Jul 17, 2012 at 01:33:47PM -0400, John Stultz wrote: > Here is backport of the leapsecond fixes to 3.0-stable. These are less > straight forward, and should get closer review. > > This patch set addresses two issues: > > 1) Deadlock leapsecond issue that a few reports described. > > I spent some time over the weekend trying to find a way to reproduce > the hard-hang issue some folks were reporting after the leapsecond. > Initially I didn't think the 6b43ae8a619d17 leap-second hrimter livelock > patch needed to be backported since, I assumed it required the ntp_lock > split for it to be triggered, but looking again I found that the same > issue could occur prior to splitting out the ntp_lock. So I've backported > that fix (and its follow-on fixups) as well as created a test case > to reproduce the hard-hang deadlock. > > > 2) Early hrtimer/futex expiration issue that was more widely observed > > This is the load-spike issue that a number of folks saw that did not > hard hang most boxes (although some reports did show nmi-watchdogs > triggering due to sudden spinning in tight loops). > > I've booted and tested this entire patchset on two boxes and run through a > number of leapsecond related stress tests. However, additional testing and > review would be appreciated. > > The original commits backported in this set are: > > Deadlock issue fixes: > --------------------- > 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d ntp: Fix leap-second hrtimer > livelock > dd48d708ff3e917f6d6b6c2b696c3f18c019feed ntp: Correct TAI offset during > leap second > fad0c66c4bb836d57a5f125ecd38bed653ca863a timekeeping: Fix CLOCK_MONOTONIC > inconsistency during leapsecond > > Helper change: (allows the following fixes to backport more easily): > -------------------------------------------------------------------- > cc06268c6a87db156af2daed6e96a936b955cc82 time: Move common updates to a > function > > Hrtimer early-expiration issue fixes: > ------------------------------- > f55a6faa384304c89cfef162768e88374d3312cb hrtimer: Provide > clock_was_set_delayed() > 4873fa070ae84a4115f0b3c9dfabc224f1bc7c51 timekeeping: Fix leapsecond > triggered load spike issue > 5b9fe759a678e05be4937ddf03d50e950207c1c0 timekeeping: Maintain ktime_t > based offsets for hrtimers > 196951e91262fccda81147d2bcf7fdab08668b40 hrtimers: Move lock held region > in hrtimer_interrupt() > f6c06abfb3972ad4914cef57d8348fcb2932bc3b timekeeping: Provide hrtimer > update function > 5baefd6d84163443215f4a99f6a20f054ef11236 hrtimer: Update hrtimer base > offsets each hrtimer_interrupt > 3e997130bd2e8c6f5aaa49d6e3161d4d29b43ab0 timekeeping: Add missing update > call in timekeeping_resume() > > > I've already done backports to all the stable kernels to 2.6.32, and > will send out the rest soon.
That's very much appreciated, thank you! Do not hesitate to send me your reproducers, I'll happily run some tests. Best regards, Willy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
