From: Keir Fraser <keir@xen.org>
Date: Fri, 14 Jan 2011 14:18:31 +0000 (+0000)
Subject: x86 acpi: Fix crash in enable_nonboot_cpus() on wakeup from S3/S4
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~10918^2~7
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https://%22%22/%22http:/www.example.com/cgi/%22https:/%22%22?a=commitdiff_plain;h=9d9af7dca878fb6f85ddf3cf3cb43df273f6b5a0;p=xen.git

x86 acpi: Fix crash in enable_nonboot_cpus() on wakeup from S3/S4

Bringing a CPU back online can require RCU work to be flushed, because
the per-cpu data from last time the CPU was online may not yet be
deallocated. Use the new rcu_barrier() interface function to achieve
this.

Signed-off-by: Keir Fraser <keir@xen.org>
---

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index b4a633d544..5dfdeb431f 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -206,6 +206,7 @@ static int enter_state(u32 state)
  enable_cpu:
     cpufreq_add_cpu(0);
     microcode_resume_cpu(0);
+    rcu_barrier();
     mtrr_aps_sync_begin();
     enable_nonboot_cpus();
     mtrr_aps_sync_end();