[PATCH] SGSN: set pctx->lib = NULL after calling pdp_freepdp(pctx->lib)

[Harald Welte]

If we don't do this, we will generate a bogus warning in
gprs_sgsn:sgsn_pdp_ctx_free() when we release a pctx which still has the
lib pointer set to non-NULL.

At the same point, we introduce an OSMO_ASSERT() to verify that the
pctx->lib really equals the pdp context which libgtp reported to us.
---
 openbsc/src/gprs/sgsn_libgtp.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/openbsc/src/gprs/sgsn_libgtp.c b/openbsc/src/gprs/sgsn_libgtp.c
index f2eb35d..c244e2c 100644
--- a/openbsc/src/gprs/sgsn_libgtp.c
+++ b/openbsc/src/gprs/sgsn_libgtp.c
@@ -264,6 +264,10 @@ static int create_pdp_conf(struct pdp_t *pdp, void *cbp, int cause)
 	DEBUGP(DGPRS, "Received CREATE PDP CTX CONF, cause=%d(%s)\n",
 		cause, get_value_string(gtp_cause_strs, cause));
 
+	/* make sure that libgtp doesn't call us with inconsistent
+	 * pointers */
+	OSMO_ASSERT(pctx->lib == pdp);
+
 	/* Check for cause value if it was really successful */
 	if (cause < 0) {
 		LOGP(DGPRS, LOGL_NOTICE, "Create PDP ctx req timed out\n");
@@ -292,8 +296,13 @@ static int create_pdp_conf(struct pdp_t *pdp, void *cbp, int cause)
 
 reject:
 	pctx->state = PDP_STATE_NONE;
-	if (pdp)
+	if (pdp) {
 		pdp_freepdp(pdp);
+		/* unlink the now non-existing library handle from the
+		 * pdp context */
+		pctx->lib = NULL;
+	}
+
 	/* Send PDP CTX ACT REJ to MS */
 	rc = gsm48_tx_gsm_act_pdp_rej(pctx->mm, pctx->ti, reject_cause,
 					0, NULL);
-- 
1.8.3.2

-- 
- Harald Welte <laforge at gnumonks.org>           http://laforge.gnumonks.org/
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