[Xen-devel] [PATCH 09/18] xen/arm: Add rcu_barrier() before enabling non-boot CPUs on resume

[Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>]

The rcu_barrier() has to be added to ensure that the per cpu area is
freed before a non-boot CPU tries to initialize it (_free_percpu_area()
has to be called before the init_percpu_area()). This scenario occurs
when non-boot CPUs are hot-unplugged on suspend and hotplugged on resume.

Signed-off-by: Mirela Simonovic <mirela.simonovic@xxxxxxxxxx>
Signed-off-by: Saeed Nowshadi <saeed.nowshadi@xxxxxxxxxx>
---
 xen/arch/arm/suspend.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/xen/arch/arm/suspend.c b/xen/arch/arm/suspend.c
index dae1b1f7d6..8e8e531d61 100644
--- a/xen/arch/arm/suspend.c
+++ b/xen/arch/arm/suspend.c
@@ -133,6 +133,7 @@ static long system_suspend(void *data)
     system_state = SYS_STATE_resume;
 
 resume_nonboot_cpus:
+    rcu_barrier();
     enable_nonboot_cpus();
     thaw_domains();
     system_state = SYS_STATE_active;
-- 
2.13.0


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