freetdm: do not write to io dump if is not enabled

diff --git a/libs/freetdm/src/ftdm_io.c b/libs/freetdm/src/ftdm_io.c
index c43d694dee266e605db5c9a0ec4694c59d4f2355..495be78ff1cc720bbd72aaa06e747093436d5a57 100644 (file)
--- a/libs/freetdm/src/ftdm_io.c
+++ b/libs/freetdm/src/ftdm_io.c
@@ -91,6 +91,10 @@ static void write_chan_io_dump(ftdm_channel_t *fchan, ftdm_io_dump_t *dump, char
        int windex = dump->windex;
        int avail = dump->size - windex;
 
+       if (!dump->buffer) {
+               return;
+       }
+
        if (dlen > avail) {
                int diff = dlen - avail;