[erlang-questions] Erlang 18.0, hanging erlang:memory(total)?

[Rickard Green]

On Thu, Jul 2, 2015 at 12:29 AM, Nico Kruber <nico.kruber@REDACTED> wrote:
> Hi folks,
> is it possible that erlang:memory/1 can hang?
>
> Today I had a unit test failing in the middle of its execution (it runs the
> same test over and over again and it was like the 20th time it was run). There
> was a timeout (>50s) in one process not being able to finish its message
> handling and erlang:process_info(Pid, current_stacktrace) is repeatedly
> showing the following stacktrace during these 50s:
>
> {current_stacktrace,
>              [{erlang,receive_emd,3,[]},
>               {erlang,get_mem_data,3,[]},
>               {erlang,memory,1,[]},
>               {dht_node_state,details,1,
>                   [{file,"src/dht_node_state.erl"},{line,510}]},
>               {dht_node,on,2,[{file,"src/dht_node.erl"},{line,384}]},
>               {mockup_dht_node,on,2,
>                   [{file,"test/mockup_dht_node.erl"},{line,67}]},
>               {gen_component,on,3,
>                   [{file,"src/gen_component.erl"},{line,614}]}]}
>
> The line in the dht_node_state module literally only calls
> erlang:memory(total) and creates a record with this info. Apparently, it never
> gets out of erlang:memory/1 :(
>
>
> Thanks for your help
> Nico
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The bug fixed in OTP-18.0.1 (and OTP-17.5.6.1) can cause such a hang.

Regards,
Rickard
-- 
Rickard Green, Erlang/OTP, Ericsson AB