[Libwebsockets] Crash during client pipelining post

Andy Green andy at warmcat.com
Tue Mar 10 20:21:36 CET 2020

On 3/10/20 8:27 AM, Karl Vogel wrote:
> Was trying to use the PIPELINE feature in my POST client, but once I enable
> LCCSCF_PIPELINE, the client crashes when the first client gets a
> reply. Works fine if I
> don't include the pipeline option. Seems to be caused by a NULL
> pointer dereference, not
> sure if it's something I'm doing wrong or some other bug:

I could reproduce it using lws examples

./bin/lws-minimal-http-client-multi --event --post -p --h1

the main problem is although the handoff scheme for h1 pipelining is 
fine as it is, it doesn't take account of event lib -specific magic when 
doing the handover.  I pushed some patches on master that should solve 
the thing you hit, but it seems there is more to do under some 
conditions, I'll look at it tomorrow.  Please try the patches in the 

The various event lib options need elaborating out and testing in CI, 
but it's very painful trying to install the right packages on travis by 
fiddling with a script in-tree iteratively... I have plans to replace 
the external CI stuff with internal CI stuff where I can just ssh into 
each environment and set that kind of stuff up, but it's blocked by 
things out of my control atm.


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