Messages in this thread |  | | | Date | Sat, 22 Sep 2012 22:25:59 +0000 (UTC) | | From | Paul Walmsley <> | | Subject | Re: rcu self-detected stall messages on OMAP3, 4 boards |
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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
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