pkg/vcs: don't supress rcu stall reports twice

First check if the cmdline config is already present.

2 files changed, 23 insertions, 5 deletions

diff --git a/pkg/vcs/linux_configs.go b/pkg/vcs/linux_configs.go
index 3d75bc509..8d972edd3 100644
--- a/pkg/vcs/linux_configs.go
+++ b/pkg/vcs/linux_configs.go
@@ -107,11 +107,11 @@ func setLinuxSanitizerConfigs(cf *kconfig.ConfigFile, types []crash.Type, dt deb
 			cf.Unset("HARDLOCKUP_DETECTOR")
 			cf.Unset("DETECT_HUNG_TASK")
 			// It looks like it's the only reliable way to completely disable hung errors.
-			val := cf.Value("CMDLINE")
-			pos := strings.LastIndexByte(val, '"')
-			if pos >= 0 {
-				cf.Set("CMDLINE",
-					val[:pos]+" rcupdate.rcu_cpu_stall_suppress=1"+val[pos:])
+			cmdline := cf.Value("CMDLINE")
+			pos := strings.LastIndexByte(cmdline, '"')
+			const rcuStallSuppress = "rcupdate.rcu_cpu_stall_suppress=1"
+			if pos >= 0 && !strings.Contains(cmdline, rcuStallSuppress) {
+				cf.Set("CMDLINE", cmdline[:pos]+" "+rcuStallSuppress+cmdline[pos:])
 			}
 		},
 		crash.MemoryLeak: func() { cf.Unset("DEBUG_KMEMLEAK") },
diff --git a/pkg/vcs/linux_configs_test.go b/pkg/vcs/linux_configs_test.go
index 378714174..80be75db7 100644
--- a/pkg/vcs/linux_configs_test.go
+++ b/pkg/vcs/linux_configs_test.go
@@ -83,6 +83,24 @@ CONFIG_PROVE_LOCKING=y
 	}
 }
 
+// Ensure we don't add "rcupdate.rcu_cpu_stall_suppress=1" twice.
+func TestNoDoubleRcuSuppress(t *testing.T) {
+	const base = `
+CONFIG_CMDLINE="param1=a rcupdate.rcu_cpu_stall_suppress=1 param2=b"
+CONFIG_BUG=y
+CONFIG_KASAN=y
+`
+	conf, err := kconfig.ParseConfigData([]byte(base), "base")
+	if err != nil {
+		t.Fatal(err)
+	}
+	setLinuxSanitizerConfigs(conf, []crash.Type{crash.Warning}, &debugtracer.NullTracer{})
+	assert.Equal(t,
+		`"param1=a rcupdate.rcu_cpu_stall_suppress=1 param2=b"`,
+		conf.Value("CMDLINE"),
+	)
+}
+
 func assertConfigs(t *testing.T, cf *kconfig.ConfigFile, names ...string) {
 	var setConfigs []string
 	for _, name := range names {