[srslte-users] Segmentation fault during attach with mobile phone

Umberto Fattore Umberto.Fattore at neclab.eu
Tue Jul 25 16:06:59 UTC 2017


Dear Andre, 

I tried what you suggested. Attached, you can find the new log file. 

cnfg->dl_am_rlc.t_status_prohibit always has value 0 (in the log, look at the number next to "step 6"). 
For each rrc->add_bearer we have added a printf before and after the call and apparently it does not execute the function for the DRB1 setup. 

Best Regards, 
Umberto


-----Original Message-----
From: Andre Puschmann [mailto:andre.puschmann at softwareradiosystems.com] 
Sent: Donnerstag, 20. Juli 2017 22:34
To: Umberto Fattore
Cc: srslte-users at lists.softwareradiosystems.com
Subject: Re: [srslte-users] Segmentation fault during attach with mobile phone

Hi Umberto,

On 20.07.2017 14:28, Umberto Fattore wrote:
> Yes, I coded a printf after each instruction in the body of the 
> function rlc_am::configure( … ) and I realized that (for an single 
> UE), all printf are executed in sequence more than once. But, when the 
> segmentation fault occurs, the last printf executed is the one before 
> the  instruction: “poll_pdu = liblte_rrc_poll_pdu_num[“

Could you try to print the value of cnfg->dl_am_rlc.t_status_prohibit in that printf as well? I.e. "printf("%d\n",
cnfg->dl_am_rlc.t_status_prohibit);"

It shouldn't go above 64 and is valid only below 56.

Also in srsenb/upper/rrc.cc in send_connection_reconf() there are a few calls to "parent->rlc->add_bearer()" could you add printfs before all of them too to see for which bearer it fails?


> 
> {Side note: I checked again my subscription, but I result already 
> subscribed}

Not sure what's going on there either but could you please try to turn off HTML when posting on the list?

Thanks
Andre

> 
> 
> Greetings,
> Umberto
> 
> 
>  
> 
> *From:*Andre Puschmann 
> [mailto:andre.puschmann at softwareradiosystems.com]
> *Sent:* Donnerstag, 20. Juli 2017 14:08
> *To:* Umberto Fattore
> *Cc:* srslte-users at lists.softwareradiosystems.com
> *Subject:* RE: [srslte-users] Segmentation fault during attach with 
> mobile phone
> 
>  
> 
> Hi,
> The RLC AM configure function is called whenever an bearer in 
> acknowledged mode (AM) is created. By "runs for more times" you mean 
> that it's called multiple times when a single UE attaches before it crashes?
> 
> On a side note, could you please register for the list before you post 
> the next time?
> 
> Thanks
> Andre
> 
> On July 19, 2017 2:16:36 PM GMT+02:00, Umberto Fattore 
> <Umberto.Fattore at neclab.eu <mailto:Umberto.Fattore at neclab.eu>> wrote:
> 
> Hi Andre,
> 
>  
> 
> Thank you for answer. Yes, I have logs obtained running with gdb. You 
> can find them attached in this message.
> 
> In my understanding, it seems that the segmentation fault happens in 
> function rlc_am::configure( … ). In particular, I notice that this 
> runs for more times correctly, but at a certain point it arrives only 
> at 2^nd code line (poll_pdu = liblte_rrc_poll_pdu_num[ … etc  …] ) and 
> then segmentation signal is detected.
> 
> Thanks Again,
> Umberto
> 
>  
> 
> *From:*Andre Puschmann 
> [mailto:andre.puschmann at softwareradiosystems.com]
> *Sent:* Dienstag, 18. Juli 2017 22:41
> *To:* Umberto Fattore; srslte-users at lists.softwareradiosystems.com
> <mailto:srslte-users at lists.softwareradiosystems.com>
> *Subject:* Re: [srslte-users] Segmentation fault during attach with 
> mobile phone
> 
>  
> 
> Hi Umberto,
> In case of a segfault it's difficult to rely on logs or pcap because 
> they may not contain the "last messages" before death. Do you have a 
> chance to run with gdb and tell where the segfault happens?
> 
> Thanks
> Andre
> 
> On July 18, 2017 2:10:07 PM GMT+02:00, Umberto Fattore 
> <Umberto.Fattore at neclab.eu <mailto:Umberto.Fattore at neclab.eu>> wrote:
> 
> Dear all,
> 
> I am encountering a problem with srslte software. I am trying to make 
> an attach with my mobile phone. Obviously, the board I am using as 
> eNodeB is connected to an MME (OpenEPC MME on VMWare virtual machine). 
> If I try an attach with my phone, the S1AP exchange between eNodeB and 
> MME is not able to be completed, because the srslte crashes for a segmentation fault.
> 
> Could you help me understing the reason of this ?
> 
> I attach in the message both the Wireshark capture and the log srslte, 
> that I suppose could help figure out the thing.
> 
>  
> 
>  
> 
> Thanks,
> 
> Umberto
> 
>  
> 
>  
> 


--
Andre Puschmann

Software Radio Systems (SRS)
http://www.softwareradiosystems.com

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