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Bug #4117

osmo-msc crash when paging SGs after MME disconnects

Added by laforge about 1 month ago. Updated 17 days ago.

Status:
New
Priority:
Normal
Assignee:
Category:
SGs Interface
Target version:
-
Start date:
07/18/2019
Due date:
% Done:

0%

Resolution:

Description

from the nextepc mailing list:

I some situations, when the MME lost connection with the OSMO-MSC and
return this connection if I try send a MT-CSFB the OSMO-MSC is crashing.

I get this error in the log:

<0006> sgs_iface.c:470 XXXXXXXXXX state 1 conf_by_radio_contact_ind 1
<0011> sgs_iface.c:251 (sub
IMSI-724210000000003:MSISDN-5544912340003:TMSI-0x8E44F269) Tx
PAGING-REQUEST suitable MME found, but no SGS connection present!
<0005> sgs_iface.c:480
SGs-UE[0x563949b08fc0]{SGs-ASSOCIATED}: Will not Page
(no MME)
<0005> paging.c:101 Paging:
IMSI-724210000000003:MSISDN-5544912340003:TMSI-0x8E44F269 for MNCC:
establish call: Starting paging failed (rc=-22)
<0001> gsm_04_08_cc.c:1922 trans(CC
IMSI-724210000000003:MSISDN-5544912340003:TMSI-0x8E44F269 callref-0x1396
tid-255) Failed to allocate paging token.
Segmentation fault (core dumped)

saida98csfb.pcap saida98csfb.pcap 17 KB pcap file at the time of the crash laforge, 07/17/2019 11:28 PM
backtrace.txt backtrace.txt 39.9 KB backtrace full exit medeiros405, 07/18/2019 01:06 AM

History

#2 Updated by medeiros405 about 1 month ago

Hello,

Running the OSMO-MSC in debug mode like Harald ask me I get this message:

Program received signal SIGSEGV, Segmentation fault.
0x00005555555957c9 in msc_a_tx_dtap_to_i (msc_a=0x0, dtap=0x5555559acd40) at msc_a.c:1560
1560 if (msc_a->c.ran->type == OSMO_RAT_EUTRAN_SGS) {
(gdb)
(gdb)
(gdb)

The backtrace full is in attached.

Thanks

Romeu Medeiros

#3 Updated by dexter 17 days ago

Hello.

I have done some experiments in order to see if I can reproduce this. I have made sure that the UE was camping on my LTE test network. Then I have terminated the MME process and tried to initiate a call to the UE. This did not crash the MSC. Also attempting to terminate the MME did not work for me. I do not see any SGSAP activity in the pcap file, so it is more likely that the crash occurs with a paging that is initiated after the MME has been disconnected.

I suggest to try with current master of osmo-msc. It would be also good to have a detailed description of the circumstances under which the crash occurs.

Best regards.
Philipp

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