Is libc6-prof just glibc recompiled with -fno-omit-frame-pointer? I did that a couple times and found that while that fixes a few system calls, it doesn't fix all of them. I think the main issue was several syscalls being called from asm, which wasn't unsurprisingly isn't affected by -fno-omit-frame-pointer.
Right, it is. It fixed my hot-path syscalls on x86 (via read/write functions, pthread_mutex functions, etc.). But if you have syscalls called via asm outside of libc (by who?) then they need frame pointers as well.
