On 2019 Apr 23, Kees Cook wrote: > When building x86 with Clang LTO and CFI, CFI jump regions are > automatically added to the end of the .text section late in linking. As a > result, the _etext position was being labelled before the appended jump > regions, causing confusion about where the boundaries of the executable > region actually are in the running kernel, and broke at least the fault > injection code. This moves the _etext mark to outside (and immediately > after) the .text area, as it already the case on other architectures > (e.g. arm64, arm). > > Reported-and-tested-by: Sami Tolvanen <samitolva...@google.com> > Signed-off-by: Kees Cook <keesc...@chromium.org> > --- > arch/x86/kernel/vmlinux.lds.S | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S > index bad8c51fee6e..de94da2366e7 100644 > --- a/arch/x86/kernel/vmlinux.lds.S > +++ b/arch/x86/kernel/vmlinux.lds.S > @@ -141,11 +141,11 @@ SECTIONS > *(.text.__x86.indirect_thunk) > __indirect_thunk_end = .; > #endif > - > - /* End of text section */ > - _etext = .; > } :text = 0x9090 > > + /* End of text section */ > + _etext = .; > + > NOTES :text :note > > EXCEPTION_TABLE(16) :text = 0x9090 > -- > 2.17.1
This breaks the build on my system: RELOCS arch/x86/boot/compressed/vmlinux.relocs CC arch/x86/boot/compressed/early_serial_console.o CC arch/x86/boot/compressed/kaslr.o AS arch/x86/boot/compressed/mem_encrypt.o CC arch/x86/boot/compressed/kaslr_64.o Invalid absolute R_X86_64_32S relocation: _etext make[2]: *** [arch/x86/boot/compressed/Makefile:130: arch/x86/boot/compressed/vmlinux.relocs] Error 1 make[2]: *** Deleting file 'arch/x86/boot/compressed/vmlinux.relocs' make[2]: *** Waiting for unfinished jobs.... make[1]: *** [arch/x86/boot/Makefile:112: arch/x86/boot/compressed/vmlinux] Error 2 make: *** [arch/x86/Makefile:283: bzImage] Error 2 -- Regards, Johannes
