diff mbox series

gcc-plugins: drop -std=gnu++11 to fix GCC 13 build

Message ID 20230201230009.2252783-1-sam@gentoo.org
State New
Headers
Series gcc-plugins: drop -std=gnu++11 to fix GCC 13 build |

Commit Message

Sam James Feb. 1, 2023, 11 p.m. UTC 
  The latest GCC 13 snapshot (13.0.1 20230129) gives the following:
```
cc1: error: cannot load plugin ./scripts/gcc-plugins/randomize_layout_plugin.so
 :./scripts/gcc-plugins/randomize_layout_plugin.so: undefined symbol: tree_code_type
```

This ends up being because of https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=b0241ce6e37031
upstream in GCC which changes the visibility of some types used by the kernel's
plugin infrastructure like tree_code_type.

After discussion with the GCC folks, we found that the kernel needs to be building
plugins with the same flags used to build GCC - and GCC defaults to gnu++17
right now. The minimum GCC version needed to build the kernel is GCC 5.1
and GCC 5.1 already defaults to gnu++14 anyway, so just drop the flag, as
all GCCs that could be used to build GCC already default to an acceptable
version which was >= the version we forced via flags until now.

Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108634
Signed-off-by: Sam James <sam@gentoo.org>
---
 scripts/gcc-plugins/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kees Cook Feb. 2, 2023, 6:49 p.m. UTC | #1 
On Wed, 1 Feb 2023 23:00:09 +0000, Sam James wrote:
> The latest GCC 13 snapshot (13.0.1 20230129) gives the following:
> ```
> cc1: error: cannot load plugin ./scripts/gcc-plugins/randomize_layout_plugin.so
>  :./scripts/gcc-plugins/randomize_layout_plugin.so: undefined symbol: tree_code_type
> ```
> 
> This ends up being because of https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=b0241ce6e37031
> upstream in GCC which changes the visibility of some types used by the kernel's
> plugin infrastructure like tree_code_type.
> 
> [...]

Applied to for-next/hardening, thanks!

[1/1] gcc-plugins: drop -std=gnu++11 to fix GCC 13 build
      https://git.kernel.org/kees/c/5a6b64adc18d
diff mbox series

Patch

diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
index b34d11e22636..320afd3cf8e8 100644
--- a/scripts/gcc-plugins/Makefile
+++ b/scripts/gcc-plugins/Makefile
@@ -29,7 +29,7 @@  GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)
 plugin_cxxflags	= -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
 		  -include $(srctree)/include/linux/compiler-version.h \
 		  -DPLUGIN_VERSION=$(call stringify,$(KERNELVERSION)) \
-		  -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \
+		  -I $(GCC_PLUGINS_DIR)/include -I $(obj) \
 		  -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \
 		  -ggdb -Wno-narrowing -Wno-unused-variable \
 		  -Wno-format-diag