From: Ard Biesheuvel ardb@kernel.org
When using -fPIE codegen, the compiler will emit const global objects (which are useless unless statically initialized) into .data.rel.ro rather than .rodata if the object contains fields that carry absolute addresses of other code or data objects. This permits the linker to annotate such regions as requiring read-write access only at load time, but not at execution time (in user space).
This distinction does not matter for the kernel, but it does imply that const data will end up in writable memory if the .data.rel.ro sections are not treated in a special way.
So emit .data.rel.ro into the .rodata segment.
Cc: stable@vger.kernel.org Signed-off-by: Ard Biesheuvel ardb@kernel.org --- include/asm-generic/vmlinux.lds.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 02a4adb4a999..0d5b186abee8 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -457,7 +457,7 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG) . = ALIGN((align)); \ .rodata : AT(ADDR(.rodata) - LOAD_OFFSET) { \ __start_rodata = .; \ - *(.rodata) *(.rodata.*) \ + *(.rodata) *(.rodata.*) *(.data.rel.ro*) \ SCHED_DATA \ RO_AFTER_INIT_DATA /* Read only after init */ \ . = ALIGN(8); \