Comment # 17 on bug 75279 from Karl Tomlinson

> Thread 1 (Thread 0x7f2d032c2740 (LWP 3445)):
> #0  0x00007f2d02ebfa8d in read () from /usr/lib/libpthread.so.0
> #1  0x00007f2cfd97264a in mozilla::widget::GfxInfo::GetData() ()
>    from /home/fred/Téléchargements/firefox/libxul.so

I wouldn't expect a blocking read on a pipe to use 100% CPU.
Is this the same process that top is showing using the CPU?
If it is, can you use 'H' in top to identify the thread, please?