Re: 4.14.9 doesn't boot (regression)

From: Linus Torvalds
Date: Fri Dec 29 2017 - 20:35:33 EST

On Fri, Dec 29, 2017 at 5:00 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> Good. I was not feeling so happy about this bug report, but now I can
> firmly just blame the gentoo compiler for having some shit-for-brains
> "feature".

Looks like I can generate similar bad code with the F26 version of
gcc, it's just not enabled by default.

So all gentoo did was change the default options.

I suspect we should just add a

KBUILD_CFLAGS += $(call cc-option,-fno-stack-check,)

somewhere to the main Makefile, just to make sure.

Maybe like the appended?

Toralf, Alexander, does this make things JustWork(tm) for you?

Makefile | 3 +++
1 file changed, 3 insertions(+)

diff --git a/Makefile b/Makefile
index ac8c441866b7..92b74bcd3c2a 100644
--- a/Makefile
+++ b/Makefile
@@ -789,6 +789,9 @@ KBUILD_CFLAGS += $(call cc-disable-warning, pointer-sign)
# disable invalid "can't wrap" optimizations for signed / pointers
KBUILD_CFLAGS += $(call cc-option,-fno-strict-overflow)

+# Make sure -fstack-check isn't enabled (like gentoo apparently did)
+KBUILD_CFLAGS += $(call cc-option,-fno-stack-check,)
# conserve stack if available
KBUILD_CFLAGS += $(call cc-option,-fconserve-stack)