[PATCH 0/6] move mmap_area and PIE binaries away from the stack

[riel]

There are a few bugs causing the kernel to sometimes map PIE
binaries and the mmap_area where the stack is supposed to go.

This series fixes them for x86, ARM64, and PPC.
S390 seems to be ok.

If people are fine with this approach, I can work my way
through other architectures, too.