lars
Need help w/ a segmentation fault/bus error
Hi there, I’m new to this all, so please bear with me.
I rebuilt a part in our system using Flow with a couple .window_join, meaning 3 flows in total joined together. When I execute my test suite the functionality passes in about 2/3 of running mix test and in about 1/3 it crashes with segmentation fault (exit code 139). Very rarely I also get a crash w/ bus error (exit code 138) and it only once crashed writing an erl_crash.dump.
I tried to strip it down to some minimal code I could share indicating the crash, but since there are a bunch of moving parts involved, I wasn’t lucky so far.
It seems the erl_crash.dump does not contain sensitive data, please correct me, if I’m wrong here. So I could share the file, if this is helpful.
$ elixir -v
Erlang/OTP 22 [erts-10.4.4] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe] [dtrace]
Elixir 1.9.1 (compiled with Erlang/OTP 22)
What should I do? Thanks!
Most Liked
rvirding
The question is of course what the “bad header tag” means as a reason for the erlang to crash? 
I asked in the erlang slack and got the reply that it comes from a corrupted map. I am guessing, GUESSING mind you, that it may come from a NIF which constructs a badly formed map.
lars
lars
Very interesting! Thanks for looking into this @yurko!
Will likely continue the conversation here now: https://github.com/plataformatec/flow/issues/89
rvirding
What do the first 4 lines of erl_crash.dump say? Especially the line starting with “Slogan:”? It should tell you why Erlang crashed.
yurko
Ran it few times, seems to work fine:
Finished in 0.04 seconds
1 doctest, 1 test, 0 failures
Randomized with seed 511061
elixir -v
Erlang/OTP 21 [erts-10.3.4] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe]
Elixir 1.9.1 (compiled with Erlang/OTP 21)
You might want to try to downgrade your OTP. I’m on Ubuntu 18.04
Popular in Questions
Other popular topics
Latest on Elixir Forum
Sponsor Spotlight
Develop your skills with books, videos, and courses.
Categories:
Sub Categories:
Forums
Our Sponsors
Build Elixir applications with speed and confidence.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Catch errors, track performance, monitor hosts and more.
Practical resources that improve the lives of professional developers.
Producing high quality Elixir screencasts since 2017.
Enabling companies to succeed by building software people love.
Courses that'll move you from confusion to "Aha, now I get it!"