[erlang-bugs] ssl:setopts hangs indefinitely

Ingela Anderton Andin <>
Mon Oct 1 14:38:21 CEST 2012

Hi again!

Michael Gebetsroither wrote:
> Hello,
> We have a lot of gen_server processes locked up here and we suspect ssl:setopts is the cause.
> The erlang vm version used is R15B01 from debian, and i'm currently testing R15B02 packages from esl.
> (confirmed, R15B02 from esl also has this problem)
> The gen_server hang can be reproduced if we connect from a remote host over ssl to the server and remove the network
> plug, during communication. Though we couldn't reproduce the error with a local client.
> The hanging gen_server is the server process doing all the communication and housekeeping tasks on the socket.

We think that the problem might be that a fsm-process hangs in an 
ongoing gen_tcp:send, when the network connection is lost, and waiting 
for the tcp timeout (which is long) and hence the following setopts-call 
will hang as the fsm-process is busy waiting for the tcp timeout. If 
this is the case setting the tcp-option send_timeout in 
ssl:connet/accept should help your cause and the timeout will be in the 
logical place! It would be good if you can test our theory.

Regards Ingela Erlang/OTP team - Ericsson AB

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