diff --git a/src/pkg/runtime/defs_openbsd.go b/src/pkg/runtime/defs_openbsd.go
--- a/src/pkg/runtime/defs_openbsd.go
+++ b/src/pkg/runtime/defs_openbsd.go
@@ -75,6 +75,7 @@ const (
 	SIGINFO   = C.SIGINFO
 	SIGUSR1   = C.SIGUSR1
 	SIGUSR2   = C.SIGUSR2
+	SIGTHR    = C.SIGTHR
 
 	FPE_INTDIV = C.FPE_INTDIV
 	FPE_INTOVF = C.FPE_INTOVF
diff --git a/src/pkg/runtime/defs_openbsd_386.h b/src/pkg/runtime/defs_openbsd_386.h
--- a/src/pkg/runtime/defs_openbsd_386.h
+++ b/src/pkg/runtime/defs_openbsd_386.h
@@ -52,6 +52,7 @@ enum {
 	SIGINFO		= 0x1d,
 	SIGUSR1		= 0x1e,
 	SIGUSR2		= 0x1f,
+	SIGTHR		= 0x20,
 
 	FPE_INTDIV	= 0x1,
 	FPE_INTOVF	= 0x2,
diff --git a/src/pkg/runtime/defs_openbsd_amd64.h b/src/pkg/runtime/defs_openbsd_amd64.h
--- a/src/pkg/runtime/defs_openbsd_amd64.h
+++ b/src/pkg/runtime/defs_openbsd_amd64.h
@@ -52,6 +52,7 @@ enum {
 	SIGINFO		= 0x1d,
 	SIGUSR1		= 0x1e,
 	SIGUSR2		= 0x1f,
+	SIGTHR		= 0x20,
 
 	FPE_INTDIV	= 0x1,
 	FPE_INTOVF	= 0x2,
diff --git a/src/pkg/runtime/os_openbsd.c b/src/pkg/runtime/os_openbsd.c
--- a/src/pkg/runtime/os_openbsd.c
+++ b/src/pkg/runtime/os_openbsd.c
@@ -270,6 +270,15 @@ runtime·badsignal(int32 sig)
 	if (sig == SIGPROF) {
 		return;  // Ignore SIGPROFs intended for a non-Go thread.
 	}
+	if (sig == SIGURG ||
+	    sig == SIGCONT ||
+	    sig == SIGCHLD ||
+	    sig == SIGIO ||
+	    sig == SIGWINCH ||
+	    sig == SIGINFO ||
+	    sig == SIGTHR) {
+		return;  // Ignore signals with no default action.
+	}
 	runtime·write(2, badsignal, sizeof badsignal - 1);
 	if (0 <= sig && sig < NSIG) {
 		// Can't call findnull() because it will split stack.