profiling doesn't seem to work

[io.github.apitrace at io7m.com]

On 2014-08-02T10:15:21 +0000
<io.github.apitrace at io7m.com> wrote:
> 
> When attempting to profile any trace, I get "Process exited with
> non-zero exit code" in the status bar at the bottom of the main window
> and the profiling results are always blank.

Tracing with strace -f, I see the following:

[pid 25884] write(1, "Error: Cannot run profile, GL_ARB_occlusion_query extension is not supported.\n", 78) = 78
[pid 25879] <... select resumed> )      = 1 (in [15])
[pid 25879] ioctl(15, FIONREAD, [78])   = 0
[pid 25879] read(15, "Error: Cannot run profile, GL_ARB_occlusion_query extension is not supported.\n", 78) = 78
[pid 25879] select(22, [15 17 21], [], NULL, NULL <unfinished ...>
[pid 25884] close(5)                    = 0
[pid 25884] munmap(0x7f829deb4000, 1052672) = 0
[pid 25884] munmap(0x7f82965b0000, 1224704) = 0
[pid 25884] exit_group(-1)              = ?
[pid 25883] +++ exited with 255 +++
[pid 25879] <... select resumed> )      = 2 (in [15 17])

My program doesn't use that extension (or any extension, for that
matter), so... What's causing this? Is that an extension required for
profiling?

M