Blackfin: don't walk VMAs when oopsing

If we're double faulting, then we have to assume the VMAs are not safe as
broken pointers here will prevent full trace output for the double fault.
Shouldn't be a big problem though as rarely is a double fault caused by
code in userspace.
Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/kernel/traps.c

@@ -119,6 +119,15 @@ static void decode_address(char *buf, unsigned long address)
 		return;
 	}
 
+	/*
+	 * Don't walk any of the vmas if we are oopsing, it has been known
+	 * to cause problems - corrupt vmas (kernel crashes) cause double faults
+	 */
+	if (oops_in_progress) {
+		strcat(buf, "/* kernel dynamic memory (maybe user-space) */");
+		return;
+	}
+
 	/* looks like we're off in user-land, so let's walk all the
 	 * mappings of all our processes and see if we can't be a whee
 	 * bit more specific