* Corentin Labbe <clabbe.montjoie@xxxxxxxxx> [181112 06:13]: > On Sat, Nov 10, 2018 at 10:09:19AM -0800, Olof Johansson wrote: > > On Thu, Nov 8, 2018 at 7:49 AM Tony Lindgren <tony@xxxxxxxxxxx> wrote: > > > > > > * Olof Johansson <olof@xxxxxxxxx> [181107 09:28]: > > > > On Wed, Nov 7, 2018 at 9:17 AM Linus Torvalds > > > > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > > On Wed, Nov 7, 2018 at 9:10 AM Olof Johansson <olof@xxxxxxxxx> wrote: > > > > > > > > > > > > ARM: SoC fixes > > > > > > > > > > Pulled. > > > > > > > > > > > I was a bit too trigger happy to enable PREEMPT on multi_v7_defconfig, > > > > > > and it ended up regressing at least BeagleBone XM boards. > > > > > > > > > > Odd. Did it hit some "may_sleep()" test in a driver that is hidden by > > > > > preempt being off? Otherwise I don't see how/why preempt should fail > > > > > in a board-specific manner.. > > > > > > > > The board hangs early during boot and the usual way of collecting > > > > early console doesn't seem to work when attempted (I haven't tried > > > > personally). > > > > > > > > It's one of the major non-SMP platforms covered by tests. I'd be > > > > surprised if it turns out to be truly _board_ specific (and rather > > > > specific to OMAP3), but we don't have enough data yet. Chances are it > > > > either shuffles some timing around or indeed hits a may_sleep() test > > > > somewhere. > > > > > > > > (I just realized I might have missed to attribute Guillaume in the > > > > revert patch. Sorry about that). > > > > > > Looks like we're missing the stdout-path for earlycon, maybe try > > > with the following patch? I can't find my Beagleboard-xm right now, > > > time to clean-up a bit I guess. > > > > > > At least omap3-evm, logicpd-torpedo and n900 all boot with PREEMPT. > > > > To follow up on this, it turned out to be an issue where the kernel > > outgrew the location it was loaded to, and overwrite the device tree > > on decompression. So, not a code issue. > > > > It's a known fragile aspect on some of the u-boot setups, and > > something I've been hit by myself on my farm a few times. > > > > Still, for now we'll keep PREEMPT off until next merge window. > > > > Hello > > Note that CONFIG_PREEMPT cause some errors also on sun8i-a83t-bananapi-m3 > Already reported https://lkml.org/lkml/2017/12/29/139 Also thread "[PATCH v1 1/5] drivercore: Revert "deferral race condition fix" is reverting commit 58b116bce136 ("drivercore: deferral race condition fix") which has CONFIG_PREEMPT mentioned in the log. So more testing is probably needed in Linux next before enabling CONFIG_PREEMPT again. Regards, Tony
