binfmt_elf: fix PIE execution with randomization disabled

binfmt_elf: fix PIE execution with randomization disabled

The case of address space randomization being disabled in runtime through
randomize_va_space sysctl is not treated properly in load_elf_binary(),
resulting in SIGKILL coming at exec() time for certain PIE-linked binaries
in case the randomization has been disabled at runtime prior to calling
exec().

Handle the randomize_va_space == 0 case the same way as if we were not
supporting .text randomization at all.

Based on original patch by H.J. Lu and Josh Boyer.

Signed-off-by: Jiri Kosina <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Russell King <[email protected]>
Cc: H.J. Lu <[email protected]>
Cc: <[email protected]>
Tested-by: Josh Boyer <[email protected]>
Acked-by: Nicolas Pitre <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>