Re: [QUESTION] Compile error on ppc32 with compilation option '-fdata-sections'

[Kees Cook <keescook@chromium.org>]

On Tue, Oct 19, 2021 at 10:14:34AM +0800, Ye Weihua wrote:
> Hi,
> 
> 
> When I was compiling the ppc32 kernel with the compilation option
> '-fdata-sections', a compilation error occurred and the message was as
> follows:
> 
> 
>     "Inconsistent kallsyms data
> 
>     Try make KALLSYMS_EXTRA_PASS=1 as a workaround"
> 
> 
> After comparing the symbol tables, I found that the "_end" and "__bss_stop"
> positions in Symtem.map and tmp_System.map are different: in Symtem.map they
> are in the middle of the symbol table. In tmp_System.map, they are at the
> end of the symbol table.
> 
> 
> commit af73d78bd384aa9b add "strip-debug" to improve performance. However,
> the addition takes effect only for tmp_vmlinux but not for vmlinux. As a
> result, the symbol tables are different after the "-fdata-sections"
> compilation option is enabled.
> 
> 
> How the "strip-debug" compilation option affects symbol table order?
> 
> Can "strip-debug" be added during vmlinux generation?

How did you add -fdata-sections? There needs to be a lot of special
handling to use that option...

-- 
Kees Cook