fös., 22. feb. 2019 kl. 14:10 skrifaði Andri Yngvason <andri@xxxxxxxxxxx>:
>
> The kernel stalls very early in the boot process. Nothing's even
> printed to the console with earlyprintk. This can be reproduced using
> qemu:
> $ ARCH=x86 make i386_defconfig
> $ ARCH=x86 make menuconfig # And select preempt rt full
> $ ARCH=x86 make all
> $ qemu-system-i386 -kernel arch/x86/boot/bzImage
>
> I've tried the same with 4.18-rt and an earlier version of 4.19-rt.
> The kernel boots on 4.18-rt, but not any version of 4.19-rt. It also
> boots fine if I use the default scheduling method.
>
Disabling lazy preempt like this "fixes" the problem:
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 28f8cd79aa74..8c56260bdf84 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -180,7 +180,6 @@ config X86
select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS &&
HAVE_PERF_EVENTS_NMI
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
- select HAVE_PREEMPT_LAZY
select HAVE_RCU_TABLE_FREE if PARAVIRT
select HAVE_RCU_TABLE_INVALIDATE if HAVE_RCU_TABLE_FREE
select HAVE_REGS_AND_STACK_ACCESS_API
