Because attaching a debugger to the Linux Kernel is so convenient and easy :P
But yeah, I was just being lazy and dumb. I solved it within ten minutes of someone saying "why don't you just go through the binfmt_elf code?" A debugger would've probably been more tedious than reading the relevant code directly, but would've been just as effective.
It's not and actually I do find it kind of amusing that Linux is possibly the hardest of the three main OSes to get a debugging set up for, but yeah I've had to do it enough that I don't mind doing and I can probably get it set up in a few minutes. Plus if the bug isn't in some architecture specific or hardware dependent thing there's this Linux compatibility userspace layer I help out on sometimes that is much easier to work with. And if it's that easy, I will generally choose to that instead of having to actually think about what I am doing ;)
But yeah, I was just being lazy and dumb. I solved it within ten minutes of someone saying "why don't you just go through the binfmt_elf code?" A debugger would've probably been more tedious than reading the relevant code directly, but would've been just as effective.