| Message ID | alpine.DEB.2.10.1612071049530.22778@sstabellini-ThinkPad-X260 (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c index 90ad1d0..c841a15 100644 --- a/xen/arch/arm/smpboot.c +++ b/xen/arch/arm/smpboot.c @@ -311,7 +311,6 @@ void start_secondary(unsigned long boot_phys_offset, /* Now report this CPU is up */ cpumask_set_cpu(cpuid, &cpu_online_map); - smp_wmb(); local_irq_enable(); local_abort_enable(); @@ -408,6 +407,7 @@ int __cpu_up(unsigned int cpu) cpu_relax(); process_pending_softirqs(); } + smp_rmb(); /* * Nuke start of day info before checking one last time if the CPU
Remove useless smp_wmb() barrier after cpumask_set_cpu(cpuid, &cpu_online_map), which is not synchronizing against anything. Keep the other smp_wmb(), before the cpumask_set_cpu call, to ensure that all writes before setting the cpu online are visible to other cpus. For that to work properly, we need a corresponding smp_rmb() barrier, after reading the online cpumask from other processors, which is currently missing. Add it. See: http://marc.info/?l=xen-devel&m=148093236307211 Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>