diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index d3bccd0dd1c..e0bc937b6e8 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -3030,8 +3030,10 @@ postsig(int sig)
 		/*
 		 * If we get here, the signal must be caught.
 		 */
-		KASSERT(action != SIG_IGN && !SIGISMEMBER(td->td_sigmask, sig),
-		    ("postsig action"));
+		KASSERT(action != SIG_IGN, ("postsig action %p", action));
+		KASSERT(!SIGISMEMBER(td->td_sigmask, sig),
+		    ("postsig action: blocked sig %d", sig));
+
 		/*
 		 * Set the new mask value and also defer further
 		 * occurrences of this signal.