diff --git a/[refs] b/[refs]
index 96f8710e6a39..a33fa7c062a4 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bd399063976c6c7a09beb4730ed1d93cadbcc739
+refs/heads/master: ce37defc0f6673f5ca2c92ed5cfcaf290ae7dd16
diff --git a/trunk/arch/x86/include/asm/msr.h b/trunk/arch/x86/include/asm/msr.h
index 084ef95274cd..95203d40ffdd 100644
--- a/trunk/arch/x86/include/asm/msr.h
+++ b/trunk/arch/x86/include/asm/msr.h
@@ -169,7 +169,14 @@ static inline int wrmsr_safe(unsigned msr, unsigned low, unsigned high)
 	return native_write_msr_safe(msr, low, high);
 }
 
-/* rdmsr with exception handling */
+/*
+ * rdmsr with exception handling.
+ *
+ * Please note that the exception handling works only after we've
+ * switched to the "smart" #GP handler in trap_init() which knows about
+ * exception tables - using this macro earlier than that causes machine
+ * hangs on boxes which do not implement the @msr in the first argument.
+ */
 #define rdmsr_safe(msr, p1, p2)					\
 ({								\
 	int __err;						\