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Date: Wed, 3 Oct 2012 18:08:52 +0100
From: Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>
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To: Ian Campbell <Ian.Campbell@citrix.com>
CC: Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>,
        "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH] xen/xen_initial_domain: check that xen_start_info is
 initialized
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Since commit commit 4c071ee5268f7234c3d084b6093bebccc28cdcba ("arm:
initial Xen support") PV on HVM guests can be xen_initial_domain.
However PV on HVM guests might have an unitialized xen_start_info, so
check before accessing its fields.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/include/xen/xen.h b/include/xen/xen.h
index 9a39ca5..e7101bb 100644
--- a/include/xen/xen.h
+++ b/include/xen/xen.h
@@ -28,7 +28,7 @@ extern enum xen_domain_type xen_domain_type;
 #include <asm/xen/hypervisor.h>
 
 #define xen_initial_domain()	(xen_domain() && \
-				 xen_start_info->flags & SIF_INITDOMAIN)
+				 xen_start_info && xen_start_info->flags & SIF_INITDOMAIN)
 #else  /* !CONFIG_XEN_DOM0 */
 #define xen_initial_domain()	(0)
 #endif	/* CONFIG_XEN_DOM0 */