boot/grub2: workaround breakage with -O2, -O3 build

When grub2 (i386-pc) is built with -O2 or -O3 it is unable to boot
and the system will reboot in a loop.

Tony Battersby has bisected [0] the error down to this security bugfix:
boot/grub2/0132-kern-parser-Fix-a-stack-buffer-overflow.patch
There is also a bug report by Peter Seiderer about this [1].

As discussed on the mailing list [2], this patch introduces a workaround
in the grub2.mk overriding the global optimization settings with -Os
which results in a booting system.

References:
[0] https://savannah.gnu.org/bugs/?60458
[1] https://bugs.busybox.net/show_bug.cgi?id=13586
[2] http://lists.busybox.net/pipermail/buildroot/2021-May/311524.html

Signed-off-by: Andreas Hilse <andreas.hilse@googlemail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

diff --git a/boot/grub2/grub2.mk b/boot/grub2/grub2.mk
index af16ee91e1775990561b08a01070e30d008ff1ae..52e9199ae9cc1fd71e8c98a5b50877d685f5f820 100644 (file)
--- a/boot/grub2/grub2.mk
+++ b/boot/grub2/grub2.mk
@@ -118,9 +118,11 @@ HOST_GRUB2_CONF_ENV = \
 GRUB2_CONF_ENV = \
        CPP="$(TARGET_CC) -E" \
        TARGET_CC="$(TARGET_CC)" \
-       TARGET_CFLAGS="$(TARGET_CFLAGS)" \
-       TARGET_CPPFLAGS="$(TARGET_CPPFLAGS) -fno-stack-protector" \
-       TARGET_LDFLAGS="$(TARGET_LDFLAGS)" \
+       CFLAGS="$(TARGET_CFLAGS) -Os" \
+       TARGET_CFLAGS="$(TARGET_CFLAGS) -Os" \
+       CPPFLAGS="$(TARGET_CPPFLAGS) -Os -fno-stack-protector" \
+       TARGET_CPPFLAGS="$(TARGET_CPPFLAGS) -Os -fno-stack-protector" \
+       TARGET_LDFLAGS="$(TARGET_LDFLAGS) -Os" \
        TARGET_NM="$(TARGET_NM)" \
        TARGET_OBJCOPY="$(TARGET_OBJCOPY)" \
        TARGET_STRIP="$(TARGET_CROSS)strip"