diff --git a/sys/kern/kern_entropy.c b/sys/kern/kern_entropy.c
index 944509adebc6..c418df88668d 100644
--- a/sys/kern/kern_entropy.c
+++ b/sys/kern/kern_entropy.c
@@ -2169,6 +2169,7 @@ rnd_add_data_intr(struct krndsource *rs, const void *buf, uint32_t len,
  *	held, and false for callers from thread or soft interrupt
  *	context and no spin locks held.
  */
+#include <ddb/ddb.h>
 static void
 rnd_add_data_internal(struct krndsource *rs, const void *buf, uint32_t len,
     uint32_t entropybits, bool intr_p)
@@ -2180,6 +2181,12 @@ rnd_add_data_internal(struct krndsource *rs, const void *buf, uint32_t len,
 	    " %"PRIu32" bits in %"PRIu32"-byte string",
 	    rs ? rs->name : "(anonymous)", entropybits, len);
 
+	if (rs && strcmp(rs->name, "efirng") == 0) {
+		printf("%s: entering %u-byte sample (%u bits of entropy)\n",
+		    rs->name, len, entropybits);
+		db_stacktrace();
+	}
+
 	/*
 	 * Hold up the reset xcall before it zeroes the entropy counts
 	 * on this CPU or globally.  Otherwise, we might leave some