diff --git a/lib/lkp_pattern.rb b/lib/lkp_pattern.rb
index c488a0b74..fa8010621 100755
--- a/lib/lkp_pattern.rb
+++ b/lib/lkp_pattern.rb
@@ -30,7 +30,7 @@ def regexp
                   .reject(&:empty?)
                   .reject { |line| line.start_with?('#') }
 
-      @regexp = Regexp.new lines.join('|')
+      @regexp = Regexp.new "(#{lines.join('|')})"
     end
 
     def patterns
diff --git a/spec/stats/dmesg/82 b/spec/stats/dmesg/82
new file mode 100644
index 000000000..a1a2ed635
--- /dev/null
+++ b/spec/stats/dmesg/82
@@ -0,0 +1 @@
+[    0.861994] sysctl could not get directory: /debug/test_sysctl/mnt/mnt_error -30
diff --git a/spec/stats/dmesg/82.yaml b/spec/stats/dmesg/82.yaml
new file mode 100644
index 000000000..c37c7c9c8
--- /dev/null
+++ b/spec/stats/dmesg/82.yaml
@@ -0,0 +1,9 @@
+boot_failures: 1
+
+# sysctl could not get directory:
+sysctl_could_not_get_directory: 1
+message:sysctl_could_not_get_directory: [    0.861994] sysctl could not get directory: /debug/test_sysctl/mnt/mnt_error -30
+pattern:sysctl_could_not_get_directory: sysctl could not get directory:
+
+timestamp:last: 0.861994
+timestamp:sysctl_could_not_get_directory: 0.861994