On Sat, 22 Sep 2012, Paul E. McKenney wrote: > And here is a patch. I am still having trouble reproducing the problem, > but figured that I should avoid serializing things. Thanks, testing this now on v3.6-rc6. One question though about the patch description: > All this begs the question of exactly how a callback-free grace period > gets started in the first place. This can happen due to the fact that > CPUs do not necessarily agree on which grace period is in progress. > If a CPU still believes that the grace period that just completed is > still ongoing, it will believe that it has callbacks that need to wait > for another grace period, never mind the fact that the grace period > that they were waiting for just completed. This CPU can therefore > erroneously decide to start a new grace period. Doesn't this imply that this bug would only affect multi-CPU systems? The recent tests here have been on Pandaboard, which is dual-CPU, but my recollection is that I also observed the warnings on a single-core Beagleboard. Will re-test. - Paul -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
