# DF-2409 fix (authored post-verification; not applied to sys/)
--- a/sys/dev/crypto/tpm/tpm20.c
+++ b/sys/dev/crypto/tpm/tpm20.c
@@ -201,6 +201,8 @@ tpm20_release(struct tpm_sc *sc)
 
 #ifdef TPM_HARVEST
 	callout_drain(&sc->harvest_callout);
 #endif
+	callout_drain(&sc->discard_buffer_callout);
+
 	if (sc->buf != NULL)
 		kfree(sc->buf, M_TPM20);