diff --git a/proc/arch.go b/proc/arch.go
index 7fedbc54..fd716745 100644
--- a/proc/arch.go
+++ b/proc/arch.go
@@ -37,7 +37,7 @@ func (a *AMD64) SetGStructOffset(ver GoVersion, isextld bool) {
 		a.gStructOffset = 0x8a0
 	case "linux":
 		a.gStructOffset = 0xfffffffffffffff0
-		if isextld || ver.AfterOrEqual(GoVersion{1, 5, -1, 2}) || ver.IsDevel() {
+		if isextld || ver.AfterOrEqual(GoVersion{1, 5, -1, 2, 0}) || ver.IsDevel() {
 			a.gStructOffset += 8
 		}
 	}
diff --git a/proc/go_version.go b/proc/go_version.go
index 752c8d64..88a89b96 100644
--- a/proc/go_version.go
+++ b/proc/go_version.go
@@ -10,6 +10,7 @@ type GoVersion struct {
 	Minor int
 	Rev   int
 	Beta  int
+	RC    int
 }
 
 func parseVersionString(ver string) (GoVersion, bool) {
@@ -17,7 +18,7 @@ func parseVersionString(ver string) (GoVersion, bool) {
 	var err1, err2, err3 error
 
 	if strings.HasPrefix(ver, "devel") {
-		return GoVersion{-1, 0, 0, 0}, true
+		return GoVersion{-1, 0, 0, 0, 0}, true
 	}
 
 	if strings.HasPrefix(ver, "go") {
@@ -25,14 +26,21 @@ func parseVersionString(ver string) (GoVersion, bool) {
 		switch len(v) {
 		case 2:
 			r.Major, err1 = strconv.Atoi(v[0])
-			v = strings.SplitN(v[1], "beta", 2)
-			if len(v) != 2 {
+			vr := strings.SplitN(v[1], "beta", 2)
+			if len(vr) == 2 {
+				r.Beta, err3 = strconv.Atoi(vr[1])
+			} else {
+				vr = strings.SplitN(v[1], "rc", 2)
+				if len(vr) == 2 {
+					r.RC, err3 = strconv.Atoi(vr[1])
+				}
+			}
+			if len(vr) < 2 {
 				return GoVersion{}, false
 			}
 
-			r.Minor, err2 = strconv.Atoi(v[0])
+			r.Minor, err2 = strconv.Atoi(vr[0])
 			r.Rev = -1
-			r.Beta, err3 = strconv.Atoi(v[1])
 
 			if err1 != nil || err2 != nil || err3 != nil {
 				return GoVersion{}, false
@@ -82,6 +90,10 @@ func (a *GoVersion) AfterOrEqual(b GoVersion) bool {
 		return false
 	}
 
+	if a.RC < b.RC {
+		return false
+	}
+
 	return true
 }
 
diff --git a/proc/proc_test.go b/proc/proc_test.go
index 4f7225c8..d02d4cb0 100644
--- a/proc/proc_test.go
+++ b/proc/proc_test.go
@@ -668,9 +668,10 @@ func versionAfterOrEqual(t *testing.T, verStr string, ver GoVersion) {
 }
 
 func TestParseVersionString(t *testing.T) {
-	versionAfterOrEqual(t, "go1.5.0", GoVersion{1, 5, 0, 0})
-	versionAfterOrEqual(t, "go1.4.2", GoVersion{1, 4, 2, 0})
-	versionAfterOrEqual(t, "go1.5beta2", GoVersion{1, 5, -1, 2})
+	versionAfterOrEqual(t, "go1.5.0", GoVersion{1, 5, 0, 0, 0})
+	versionAfterOrEqual(t, "go1.4.2", GoVersion{1, 4, 2, 0, 0})
+	versionAfterOrEqual(t, "go1.5beta2", GoVersion{1, 5, -1, 2, 0})
+	versionAfterOrEqual(t, "go1.5rc2", GoVersion{1, 5, -1, 0, 2})
 	ver, ok := parseVersionString("devel +17efbfc Tue Jul 28 17:39:19 2015 +0000 linux/amd64")
 	if !ok {
 		t.Fatalf("Could not parse devel version string")