diff -u -r1.812 chan_sip.c
--- channels/chan_sip.c 23 Aug 2005 01:50:11 -0000      1.812
+++ channels/chan_sip.c 23 Aug 2005 10:21:19 -0000
@@ -1014,6 +1014,11 @@
        struct sip_history *hist, *prev;
        char *c;

+       if (p == NULL) {
+               ast_log(LOG_WARNING, "append_history() called with null sip_pvt");
+               return 0;
+       }
+
        if (!recordhistory)
                return 0;
        if(!(hist = malloc(sizeof(struct sip_history)))) {