[Xen-changelog] [xen master] x86/mm: Avoid NULL dereference when checking altp2m's for shareability

[patchbot@xxxxxxx]

commit 3b54cffcdf86485dd336f71419d3bfc7106ca56c
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Jul 27 18:54:16 2016 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Mon Aug 1 17:44:32 2016 +0100

    x86/mm: Avoid NULL dereference when checking altp2m's for shareability
    
    Coverity identifies that __get_gfn_type_access() unconditionally writes to 
its
    type parameter under a number of circumstances.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
---
 xen/arch/x86/mm/mem_sharing.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index 47e0820..14952ce 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -870,6 +870,7 @@ int mem_sharing_nominate_page(struct domain *d,
         unsigned int i;
         struct p2m_domain *ap2m;
         mfn_t amfn;
+        p2m_type_t ap2mt;
         p2m_access_t ap2ma;
 
         altp2m_list_lock(d);
@@ -880,7 +881,7 @@ int mem_sharing_nominate_page(struct domain *d,
             if ( !ap2m )
                 continue;
 
-            amfn = get_gfn_type_access(ap2m, gfn, NULL, &ap2ma, 0, NULL);
+            amfn = get_gfn_type_access(ap2m, gfn, &ap2mt, &ap2ma, 0, NULL);
             if ( mfn_valid(amfn) && (mfn_x(amfn) != mfn_x(mfn) || ap2ma != 
p2ma) )
             {
                 altp2m_list_unlock(d);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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