From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Thu, 25 Jun 2015 12:57:04 +0000 (+0200)
Subject: x86/traps: avoid using current too early on boot
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~3027
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=142473cfce41a565898e0fa33dc98a1f5e41abe4;p=xen.git

x86/traps: avoid using current too early on boot

Early on boot, current has the sentinel value 0xfffff000.  Blindly using it in
show_registers() causes a nested failure and no useful information printed
from an early crash.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index 117a133b7f..61bd05347e 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -86,7 +86,7 @@ void show_registers(const struct cpu_user_regs *regs)
     struct cpu_user_regs fault_regs = *regs;
     unsigned long fault_crs[8];
     enum context context;
-    struct vcpu *v = current;
+    struct vcpu *v = system_state >= SYS_STATE_smp_boot ? current : NULL;
 
     if ( guest_mode(regs) && has_hvm_container_vcpu(v) )
     {