On Sat, Jun 09, 2018 at 01:42:05PM +0200, Philip Müller wrote:
> objtool ports introduced in v4.9.106 were not totally complete. Therefore
> they resulted in issues like:
>
> module: overflow in relocation type 10 val XXXXXXXXXXX
> ‘usbcore’ likely not compiled with -mcmodel=kernel
> module: overflow in relocation type 10 val XXXXXXXXXXX
> ‘scsi_mod’ likely not compiled with -mcmodel=kernel
What is causing these messages? What arch and .config?
> Missing part was the complete backport of commit e390f9a.
Ah, right, I missed those other parts of this commit, good catch.
>
> Original notes by Josh Poimboeuf:
>
> The '__unreachable' and '__func_stack_frame_non_standard' sections are
> only used at compile time. They're discarded for vmlinux but they
> should also be discarded for modules.
>
> Since this is a recurring pattern, prefix the section names with
> ".discard.". It's a nice convention and vmlinux.lds.h already discards
> such sections.
>
> Also remove the 'a' (allocatable) flag from the __unreachable section
> since it doesn't make sense for a discarded section.
>
> Signed-off-by: Philip Müller <philm@xxxxxxxxxxx>
> Fixes: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead
> ends")
> Link: https://gitlab.manjaro.org/packages/core/linux49/issues/2
> diff -Npur linux-4.9.106.orig/arch/x86/kernel/vmlinux.lds.S linux-4.9.106/arch/x86/kernel/vmlinux.lds.S
> --- linux-4.9.106.orig/arch/x86/kernel/vmlinux.lds.S 2018-06-09 12:43:04.238314000 +0200
> +++ linux-4.9.106/arch/x86/kernel/vmlinux.lds.S 2018-06-09 12:44:39.034361441 +0200
> @@ -352,8 +352,6 @@ SECTIONS
> DISCARDS
> /DISCARD/ : {
> *(.eh_frame)
> - *(__func_stack_frame_non_standard)
> - *(__unreachable)
> }
> }
>
> diff -Npur linux-4.9.106.orig/include/linux/compiler-gcc.h linux-4.9.106/include/linux/compiler-gcc.h
> --- linux-4.9.106.orig/include/linux/compiler-gcc.h 2018-06-09 12:43:05.058337000 +0200
> +++ linux-4.9.106/include/linux/compiler-gcc.h 2018-06-09 12:45:35.779367605 +0200
> @@ -206,7 +206,7 @@
> #ifdef CONFIG_STACK_VALIDATION
> #define annotate_unreachable() ({ \
> asm("1:\t\n" \
> - ".pushsection __unreachable, \"a\"\t\n" \
> + ".pushsection .discard.unreachable\t\n" \
> ".long 1b\t\n" \
> ".popsection\t\n"); \
> })
What about the fix up to scripts/mod/modpost and module-common.lds? Are
they not needed?
thanks,
greg k-h
