rcutorture: Make kvm-recheck-rcu.sh handle truncated lines

System hangs or killed rcutorture guest OSes can result in truncated
"Reader Pipe:" lines, which can in turn result in false-positive
reader-batch near-miss warnings.  This commit therefore adjusts the
reader-batch checks to account for possible line truncation.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh

@@ -41,7 +41,21 @@ else
 		title="$title ($ngpsps/s)"
 	fi
 	echo $title $stopstate $fwdprog
-	nclosecalls=`grep --binary-files=text 'torture: Reader Batch' $i/console.log | tail -1 | awk '{for (i=NF-8;i<=NF;i++) sum+=$i; } END {print sum}'`
+	nclosecalls=`grep --binary-files=text 'torture: Reader Batch' $i/console.log | tail -1 | \
+		awk -v sum=0 '
+		{
+			for (i = 0; i <= NF; i++) {
+				sum += $i;
+				if ($i ~ /Batch:/) {
+					sum = 0;
+					i = i + 2;
+				}
+			}
+		}
+
+		END {
+			print sum
+		}'`
 	if test -z "$nclosecalls"
 	then
 		exit 0