On 12-08-17 12:17 PM, Herton Ronaldo Krzesinski wrote: > On Wed, Aug 15, 2012 at 03:47:33PM -0400, Paul Gortmaker wrote: >> From: John Stultz <john.stu...@linaro.org> >> >> ------------------- >> This is a commit scheduled for the next v2.6.34 longterm release. >> http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git >> If you see a problem with using this for longterm, please comment. >> ------------------- >> >> commit 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d upstream. >> >> This should have been backported when it was commited, but I >> mistook the problem as requiring the ntp_lock changes >> that landed in 3.4 in order for it to occur. >> >> Unfortunately the same issue can happen (with only one cpu) >> as follows: >> do_adjtimex() >> write_seqlock_irq(&xtime_lock); >> process_adjtimex_modes() >> process_adj_status() >> ntp_start_leap_timer() >> hrtimer_start() >> hrtimer_reprogram() >> tick_program_event() >> clockevents_program_event() >> ktime_get() >> seq = req_seqbegin(xtime_lock); [DEADLOCK] >> >> This deadlock will no always occur, as it requires the >> leap_timer to force a hrtimer_reprogram which only happens >> if its set and there's no sooner timer to expire. > [...] > > I remember this came through the leapsecond deadlock & hrtimer/futex > issue fixes. But I noted now commit 6b1859dba01c7d512b72d77e3fd7da8354235189 > ("ntp: Fix STA_INS/DEL clearing bug") was not included, and its changelog > says it fixes a problem introduced with this. Wouldn't it be worth/right to > also include it in 2.6.34? I didn't test etc., just detected through the > changelog/description but would expect it would be affected too. I also > noted it is missing from 3.2.y and 2.6.32.y stables, and perhaps should be > scheduled for inclusion in their cases too. >
Thanks again Herton. I've queued this and I'll keep an eye out for the pending -tip commit from John. Paul. -- 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/
