diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-12-29 17:34:43 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-02 20:33:24 +0100 |
| commit | 1cd09d4b38a26730081780168c0de79d1cd14d71 (patch) | |
| tree | d4a3fd18ce35e86b10d21ff6db3c3f9272cc6db0 /Makefile | |
| parent | 6c4db09c291a19da66512f99c4bcb378a862f9e6 (diff) | |
kbuild: add '-fno-stack-check' to kernel build options
commit 3ce120b16cc548472f80cf8644f90eda958cf1b6 upstream.
It appears that hardened gentoo enables "-fstack-check" by default for
gcc.
That doesn't work _at_all_ for the kernel, because the kernel stack
doesn't act like a user stack at all: it's much smaller, and it doesn't
auto-expand on use. So the extra "probe one page below the stack" code
generated by -fstack-check just breaks the kernel in horrible ways,
causing infinite double faults etc.
[ I have to say, that the particular code gcc generates looks very
stupid even for user space where it works, but that's a separate
issue. ]
Reported-and-tested-by: Alexander Tsoy <alexander@tsoy.me>
Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
@@ -782,6 +782,9 @@ 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) |