Debugging

[shivani agrawal]

Hi,

I run my script (wifi nodes... tcp analysis) and get this :

songster@ubuntu:~/ns-allinone-3.13/ns-3.13$ ./waf --run scratch/
Tahoe05
Waf: Entering directory `/home/songster/ns-allinone-3.13/ns-3.13/
build'
Waf: Leaving directory `/home/songster/ns-allinone-3.13/ns-3.13/build'
'build' finished successfully (7.953s)
start at channel 1
start at channel 1
start at channel 1
start at channel 1
sync to signal (power=7.60137e-13W)
sync to signal (power=7.60137e-13W)
drop packet because signal power too Small (1.34375e-13<2.51189e-13)
Command ['/home/songster/ns-allinone-3.13/ns-3.13/build/scratch/
Tahoe05'] terminated with signal SIGSEGV. Run it under a debugger to
get more information (./waf --run <program> --command-template="gdb --
args %s <args>").
songster@ubuntu:~/ns-allinone-3.13/ns-3.13$

It may seem stupid but i am lost now.
I went through a lot of tutorials/forums for what to do next or even
how to debug further...but am lost.
Even to use gdb.. how can i proceed further...?
Shall i be increasing signal power?? ( i ran this script many times
before but did not face signal power problem..latest change was to add
rate error model) If yes, then how...

Please help.

Thanks
Shivani Agrawal

[Gokul Bhat]

Hello

Perhaps the rate error model has created some issues. I have spoken in class earlier how to use gdb. Just follow the instructions that the error provides here.

./waf --run filename --command-template="gdb %s"

Once the gdb console is up,

do a plain run by executing 

(gdb) r 

Once it encounters the seg fault, check the stack by

(gdb) where

It will indicate the last known position of the control and from there you will have to back trace and locate the point of error.