clang recently added support for -Wstringop-overread [1], which is on by
default like -Wfortify-source. This breaks the usage of -Werror in the
fortify tests, resulting in the following false positive warnings in the
kernel build:
warning: unsafe memcmp() usage lacked '__read_overflow2' warning in
lib/test_fortify/read_overflow2-memcmp.c
warning: unsafe memcmp() usage lacked '__read_overflow' warning in
lib/test_fortify/read_overflow-memcmp.c
warning: unsafe memchr() usage lacked '__read_overflow' warning in
lib/test_fortify/read_overflow-memchr.c
Examining the fortify test logs shows a warning like the following in
each of the failed logs:
In file included from lib/test_fortify/read_overflow2-memcmp.c:5:
lib/test_fortify/test_fortify.h:34:2: error: 'memcmp' reading 17 bytes from a
region of size 16 [-Werror,-Wstringop-overread]
34 | TEST;
| ^
lib/test_fortify/read_overflow2-memcmp.c:3:2: note: expanded from macro 'TEST'
3 | memcmp(large, small, sizeof(small) + 1)
| ^
1 error generated.
Disable -Wstringop-overread for the fortify tests, as it defeats the
purpose of testing the Linux specific implementation of fortify, like
-Wfortify-source.
Cc: [email protected]
Closes: https://github.com/ClangBuiltLinux/linux/issues/2168
Link:
https://github.com/llvm/llvm-project/commit/86f2e71cb8d165b59ad31a442b2391e23826133e
[1]
Signed-off-by: Nathan Chancellor <[email protected]>
---
lib/test_fortify/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/lib/test_fortify/Makefile b/lib/test_fortify/Makefile
index 399cae880e1d..44cd5df41a81 100644
--- a/lib/test_fortify/Makefile
+++ b/lib/test_fortify/Makefile
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
ccflags-y := $(call cc-disable-warning,fortify-source)
+ccflags-y += $(call cc-disable-warning,stringop-overread)
quiet_cmd_test_fortify = TEST $@
cmd_test_fortify = $(CONFIG_SHELL) $(src)/test_fortify.sh \
---
base-commit: 122b52f0bab007ebeb414c8280c1def17b9ed1f4
change-id: 20260623-fix-test_fortify-for-clang-stringop-overread-df4b31b97f47
Best regards,
--
Cheers,
Nathan
