I am trying to run the UE4.6 editor on Linux, built from the head of the branch (as of a couple hours ago) on Ubuntu 14.04 with clang 3.5 and I get the following assertion (and backtrace) when launching it for the first time:
Anyone else bitten by this? Any fix or workaround available?
Thanks!
May be similar to this bug…
Running the editor in Valgrind triggers this log when building static meshes at startup (using -ansimalloc).
Interesting, we need to double check that code. Anything particular about your setup? Could you paste the log?
Sure. Here is a crash log from a previous run, without any command line option. Please tell me if you need anything else.
Interesting. This issue has been seen previously, but is not easily reproducible on our setups, which are almost exclusively NVidia with binary drivers, while on Linux I believe it has been seen on Mesa drivers only. This is baffling as memory being overwritten is not allocated by the driver, but maybe further locking/copying is somehow involved. Could you try narrowing it down?
Looks a lot like something is smashing the heap. Running the editor in Valgrind and its additional memory guarding does not trigger the crash anymore. It does show a lot of scary stuff though 
I’ll try and have a closer look at it.
I haven’t had much time to look into this but it appears overriding Forsythe::OptimizeFaces (i.e. fill newIndexList with indexList data instead of runnning the whole algorithm) makes the crash disappear. There may be something wrong in forsythtriangleorderoptimizer.cpp…