I've created an Apitrace, which is available at <https://c.1und1.de/272476645/BP4bKyxIRCejFEqUhvT3yw> and should show all OpenGL commands right up until the crash. The replay shows the same I'm seeing when launching the game.

It's hitting an error in the no error path. Did you force no error via the env var?

(In reply to Timothy Arceri from comment #2)
> It's hitting an error in the no error path. Did you force no error via the
> env var?

No, absolutely not. Unless setting GALLIUM_HUD=fps does set that as well. But I doubt it. I just ran the game without that environment variable (or any other environment variable for that matter) and got the crash again, with an similar backtrace:
> Core was generated by `/home/kai/.local/share/Steam/SteamApps/common/XCOM 2/XCOM2WotC/bin/XCOM2WotC'.
> #0  0x00007f103b46ffb5 in _mesa_is_bufferobj (obj=0x3fffe0000) at ../../../src/mesa/main/bufferobj.h:71
> 71      ../../../src/mesa/main/bufferobj.h: No such file or directory.
> [Current thread is 1 (LWP 3491)]
> (gdb) bt full
> #0  0x00007f103b46ffb5 in _mesa_is_bufferobj (obj=0x3fffe0000) at ../../../src/mesa/main/bufferobj.h:71
>         array_bit = 8589934592
> #1  0x00007f103b46ffb5 in vertex_attrib_binding (ctx=ctx@entry=0x8a9d240, vao=vao@entry=0x7f0ed926f4c0, attribIndex=attribIndex@entry=33, bindingIndex=bindingIndex@entry=33) at ../../../src/mesa/main/varray.c:143
>         array_bit = 8589934592
> #2  0x00007f103b4714d2 in vertex_attrib_binding (bindingIndex=33, attribIndex=33, vao=0x7f0ed926f4c0, ctx=0x8a9d240) at ../../../src/mesa/main/varray.c:140
>         array = 0x7f0ed9270138
>         vao = 0x7f0ed926f4c0
>         array = <optimized out>
>         effectiveStride = <optimized out>
> #3  0x00007f103b4714d2 in update_array (ctx=0x8a9d240, attrib=33, format=6408, size=4, type=5126, stride=0, normalized=0 '\000', integer=0 '\000', doubles=0 '\000', ptr=0x0, sizeMax=5) at ../../../src/mesa/main/varray.c:566
>         vao = 0x7f0ed926f4c0
>         array = <optimized out>
>         effectiveStride = <optimized out>
> #4  0x00007f103b4722ce in _mesa_VertexAttribPointer_no_error (index=<optimized out>, size=<optimized out>, type=<optimized out>, normalized=<optimized out>, stride=<optimized out>, ptr=<optimized out>) at ../../../src/mesa/main/varray.c:932
>         ctx = <optimized out>
> #5  0x000000000244b9c7 in  ()
> #6  0x00000000030e258f in  ()
> #7  0x00007f1051950494 in start_thread (arg=0x7f0f93565700) at pthread_create.c:333
>         __res = <optimized out>
>         pd = 0x7f0f93565700
>         now = <optimized out>
>         unwind_buf = 
>               {cancel_jmp_buf = {{jmp_buf = {139704873146112, 5829145187633785263, 0, 140731612099327, 0, 139708089712704, -5838232997335733841, -5853013188703098449}, mask_was_saved = 0}}, priv = {pad = {0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
>         not_first_call = <optimized out>
>         pagesize_m1 = <optimized out>
>         sp = <optimized out>
>         freesize = <optimized out>
>         __PRETTY_FUNCTION__ = "start_thread"
> #8  0x00007f104b6f8abf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:97

FWIW to clear up some confusion - our launch scripts turns on KHR_no_error for WOTC for the extra performance.

See /path/to/install/dir/XCOM2WotC/config/extra-environment.sh:2
export MESA_NO_ERROR=1

I'll take a look and see if we're hitting a GL error at this stage.

It appears some errors slipped through.

Example:
[GL_DEBUG] Error message from OpenGL API call with id 1281: GL_INVALID_VALUE error generated. <index> out of range.

We'll handle this, I'd think it should be safe to assume this is an application bug. From what I understand using a KHR_no_error context is a trust handshake that you won't trigger any error states.

(In reply to Marc Di Luzio from comment #4)
> FWIW to clear up some confusion - our launch scripts turns on KHR_no_error
> for WOTC for the extra performance.
> 
> See /path/to/install/dir/XCOM2WotC/config/extra-environment.sh:2
> export MESA_NO_ERROR=1
> 
> I'll take a look and see if we're hitting a GL error at this stage.

O(In reply to Marc Di Luzio from comment #5)
> It appears some errors slipped through.
> 
> Example:
> [GL_DEBUG] Error message from OpenGL API call with id 1281: GL_INVALID_VALUE
> error generated. <index> out of range.
> 
> We'll handle this, I'd think it should be safe to assume this is an
> application bug. From what I understand using a KHR_no_error context is a
> trust handshake that you won't trigger any error states.

Thanks for confirming. Making as resolved.

I can confirm, that commenting out the export of MESA_NO_ERROR=1 in XCOM2WotC/config/extra-environment.sh lets me launch the game. This was tested on (fully updated Debian testing as a base):
GPU: Hawaii PRO [Radeon R9 290] (ChipID = 0x67b1)
Mesa: Git:master/39a69f0692
libdrm: 2.4.82-1
LLVM: SVN:trunk/r312410 (6.0 devel)
X.Org: 2:1.19.3-2
Linux: 4.12.10
Firmware (firmware-amd-graphics): 20170823-1
libclc: Git:master/7331b0a1fa
DDX (xserver-xorg-video-amdgpu): 1.3.0-1

Cheers Kai.

That line is being removed from the default branch as we speak, while we sort out the actual error on our side. Apologies for any wasted time.

Quick update, this has now been pushed live.

Apologies for the long wait on that.