From: Nick Desaulniers ndesaulniers@google.com
stable inclusion from stable-v5.10.137 commit 8f4f2c9b98e40c699329680f9ca4f7c3a7f949ea category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 0d362be5b14200b77ecc2127936a5ff82fbffe41 upstream.
Users of GNU ld (BFD) from binutils 2.39+ will observe multiple instances of a new warning when linking kernels in the form:
ld: warning: vmlinux: missing .note.GNU-stack section implies executable stack ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker ld: warning: vmlinux has a LOAD segment with RWX permissions
Generally, we would like to avoid the stack being executable. Because there could be a need for the stack to be executable, assembler sources have to opt-in to this security feature via explicit creation of the .note.GNU-stack feature (which compilers create by default) or command line flag --noexecstack. Or we can simply tell the linker the production of such sections is irrelevant and to link the stack as --noexecstack.
LLVM's LLD linker defaults to -z noexecstack, so this flag isn't strictly necessary when linking with LLD, only BFD, but it doesn't hurt to be explicit here for all linkers IMO. --no-warn-rwx-segments is currently BFD specific and only available in the current latest release, so it's wrapped in an ld-option check.
While the kernel makes extensive usage of ELF sections, it doesn't use permissions from ELF segments.
Link: https://lore.kernel.org/linux-block/3af4127a-f453-4cf7-f133-a181cce06f73@ker... Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a... Link: https://github.com/llvm/llvm-project/issues/57009 Reported-and-tested-by: Jens Axboe axboe@kernel.dk Suggested-by: Fangrui Song maskray@google.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Wei Li liwei391@huawei.com --- Makefile | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/Makefile b/Makefile index 6808d2d53d05..412cb46c136a 100644 --- a/Makefile +++ b/Makefile @@ -985,6 +985,9 @@ KBUILD_CFLAGS += $(KCFLAGS) KBUILD_LDFLAGS_MODULE += --build-id=sha1 LDFLAGS_vmlinux += --build-id=sha1
+KBUILD_LDFLAGS += -z noexecstack +KBUILD_LDFLAGS += $(call ld-option,--no-warn-rwx-segments) + ifeq ($(CONFIG_STRIP_ASM_SYMS),y) LDFLAGS_vmlinux += $(call ld-option, -X,) endif