[OpenSIPS-Devel] [opensips] error in infinite loop "io_watch_del: BUG - trying to del fd 34 with flags 2 1" (#591)

[rgupta0110]

Hi Bogdan,
 
Almost a month ago, I have raised the issue regarding the opensips log file filling up with the following message 
 
ERROR:core:io_watch_del: BUG - trying to del fd 38 with flags 2 1
 
Now I can reproduce it every time with the following scenario:
 
1)      UAC and UAS are connected to opensips proxy with TCP transport
2)      Connections looks good
3)      Netstat shows the connection to UAC in ESTABLISHED state and the tcp_conn_lists of opensips also looks fine for that UAC
4)      Now unplug the Ethernet cable on UAC
5)      After tcp connection timeout (set to 5 mins in opensips.cfg), the tcp connection goes away from netstat as well as from tcp_conn_lists
6)      UAS tries another tcp call to the UAC which is still unplugged
7)      tcp_conn_lists shows the tcp connection to the UAC and netstat shows the connection in SYN_SENT state
8)      After the tcp connection timeout (set to 5 mins in opensips.cfg), the connection goes away from netstat however it remains there in tcp_conn_lists and at that moment the “BUG - trying to del fd 38 with flags 2 1” starts printing in infinite loop.
 
 
I looked at the source code and observed the following
 
1)      When the network cable is plugged in 
The io_watch_add happens with flag IO_WATCH_READ in tcp_main.c  when the command is CONN_NEW
2)      When the network cable is unplugged
The io_watch_add happens with flag IO_WATCH_WRITE in tcp_main.c  when the command is ASYNC_CONNECT
 
3)      While doing io_watch_del after timeout, from handle_tcpconn_ev method, io_watch_del always uses IO_WATCH_READ to delete the fd, which gives this error in case of unplugged cable.
 
Please look into this and suggest how can I fix this issue ?
 
Thanks
Rahul Gupta


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Reply to this email directly or view it on GitHub:
https://github.com/OpenSIPS/opensips/issues/591
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