From 38b387794e43ae8af46bc32cf792400328511be9 Mon Sep 17 00:00:00 2001
From: Cedric Roux <cedric.roux@eurecom.fr>
Date: Thu, 19 Jan 2017 09:57:43 +0100
Subject: [PATCH] hack in RLC AM to avoid a race
Here is the problem:
UE comes. SRB2 is configured via message to RRC.
At some point the RLC AM is created but not configured yet.
At this moment (I think) MAC calls mac_rlc_status_ind
which calls this function. But the init was not finished yet
and we have a crash below when testing mem_block != NULL.
The "solution" is to test if rlc->input_sdus is NULL.
This is a very dirty hack. I would say the solution
is to use proper locking mechanism because RLC is used
by two threads: PHY/MAC on one hand and RRC on another
hand (I think).
---
openair2/LAYER2/RLC/AM_v9.3.0/rlc_am.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/openair2/LAYER2/RLC/AM_v9.3.0/rlc_am.c b/openair2/LAYER2/RLC/AM_v9.3.0/rlc_am.c
index 1d930554873..4051a88ef29 100644
--- a/openair2/LAYER2/RLC/AM_v9.3.0/rlc_am.c
+++ b/openair2/LAYER2/RLC/AM_v9.3.0/rlc_am.c
@@ -557,6 +557,15 @@ rlc_am_mac_status_indication (
status_resp.head_sdu_is_segmented = 0;
status_resp.rlc_info.rlc_protocol_state = rlc->protocol_state;
+ /* TODO: remove this hack. Problem is: there is a race.
+ * UE comes. SRB2 is configured via message to RRC.
+ * At some point the RLC AM is created but not configured yet.
+ * At this moment (I think) MAC calls mac_rlc_status_ind
+ * which calls this function. But the init was not finished yet
+ * and we have a crash below when testing mem_block != NULL.
+ */
+ if (rlc->input_sdus == NULL) return status_resp;
+
if (rlc->last_frame_status_indication != ctxt_pP->frame) {
rlc_am_check_timer_poll_retransmit(ctxt_pP, rlc);
rlc_am_check_timer_reordering(ctxt_pP, rlc);
--
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