On Fri, 16 Mar 2018 15:55:16 +0800 Huacai Chen [off-list ref] wrote:

Call __stack_chk_guard_setup() in decompress_kernel() is too late that
stack checking always fails for decompress_kernel() itself. So remove
__stack_chk_guard_setup() and initialize __stack_chk_guard before we
call decompress_kernel().

Original code comes from ARM but also used for MIPS and SH, so fix them
together. If without this fix, compressed booting of these archs will
fail because stack checking is enabled by default (>=4.16).

...

 arch/arm/boot/compressed/head.S        | 4 ++++
 arch/arm/boot/compressed/misc.c        | 7 -------
 arch/mips/boot/compressed/decompress.c | 7 -------
 arch/mips/boot/compressed/head.S       | 4 ++++
 arch/sh/boot/compressed/head_32.S      | 8 ++++++++
 arch/sh/boot/compressed/head_64.S      | 4 ++++
 arch/sh/boot/compressed/misc.c         | 7 -------
 7 files changed, 20 insertions(+), 21 deletions(-)

Perhaps this should be split into three patches and each one routed via
the appropriate arch tree maintainer (for sh, that might be me).

But we can do it this way if the arm and mips teams can send an ack,
please?