Messages in this thread | | | Subject | Re: SMP lockup at boot on Freescale/NXP T2080 (powerpc 64) | From | Christophe Leroy <> | Date | Thu, 8 Aug 2019 10:46:35 +0200 |
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Le 07/08/2019 à 03:24, Chris Packham a écrit : > On Wed, 2019-08-07 at 11:13 +1000, Michael Ellerman wrote: >> Chris Packham <Chris.Packham@alliedtelesis.co.nz> writes: >>> >>> On Tue, 2019-08-06 at 21:32 +1000, Michael Ellerman wrote: >>> The difference between a working and non working defconfig is >>> CONFIG_PREEMPT specifically CONFIG_PREEMPT=y makes my system hang >>> at >>> boot. >>> >>> Is that now intentionally prohibited on 64-bit powerpc? >> It's not prohibitied, but it probably should be because no one really >> tests it properly. I have a handful of IBM machines where I boot a >> PREEMPT kernel but that's about it. >> >> The corenet configs don't have PREEMPT enabled, which suggests it was >> never really supported on those machines. >> >> But maybe someone from NXP can tell me otherwise. >> > > I think our workloads need CONFIG_PREEMPT=y because our systems have > switch ASIC drivers implemented in userland and we need to be able to > react quickly to network events in order to prevent loops. We have seen > instances of this not happening simply because some other process is in > the middle of a syscall. > > One thing I am working on here is a setup with a few vendor boards and > some of our own kit that we can test the upstream kernels on. Hopefully > that'd make these kinds of reports more timely rather than just > whenever we decide to move to a new kernel version. > >
The defconfig also sets CONFIG_DEBUG_PREEMPT. Have you tried without CONFIG_DEBUG_PREEMPT ?
Christophe
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