Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Tue, 24 Mar 2020 14:20:08 +0100
From: Julio Guerra <julio@...een.com>
To: musl@...ts.openwall.com
Subject: Re: [Bug] Do not ignore membarrier return code

Hello Rich,

Here are more details on what we did to reproduce the issue.
You can clone this gist
https://gist.github.com/vdeturckheim/d420310e272f525824d7e92e7e875024
and have a look at the run.sh file example in order to get started
with it. The test.js file does a require of the js bindings of grpc,
which involves the dlopen.

What we observed yesterday with this example was:
- It crashed approximately 9 times out of 10 on aws codebuild with the
machine BUILD_GENERAL1_SMALL (3 GB memory, 2 vCPUs).
- It worked all the time by only adding membarrier to the seccomp
profile of the docker run.

But I wanted to give you more details with stack traces of the
segfault by retrying today with gdb but I cannot reproduce it
anymore...!
I'll retry later to see if I see the error again...

If what you say about membarrier is true, I think there may be some
synchronization side-effect of the syscall since, afaik, node uses
threads in order to load the shared libraries in the libuv.

-- 
Julio

Powered by blists - more mailing lists

Your e-mail address:

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.