On Mon, Mar 28, 2022 at 9:57 PM Alexander Egorenkov <egorenar@linux.ibm.com> wrote:

> Where does the symbol '.rodata' come from ?
> I couldn't find it in x86's vmlinux with nm as well.
>
 
 The "nm -a" option may be a good choice.

> On Fedora 34:
>
> $ nm /usr/lib/debug/lib/modules/5.16.16-100.fc34.x86_64/vmlinux | grep rodata
> ffffffff82c1d000 D __end_rodata
> ffffffff82e00000 D __end_rodata_aligned
> ffffffff82e00000 D __end_rodata_hpage_align
> ffffffff81199420 t frob_rodata
> ffffffff81c3eec7 T mark_rodata_ro
> ffffffff826dd200 D rodata_enabled
> ffffffff82e2cec0 d rodata_resource
> ffffffff81352690 T rodata_test
> ffffffff81c50238 t rodata_test.cold
> ffffffff8223d9d0 d rodata_test_data
> ffffffff836c2c36 t set_debug_rodata
> ffffffff838ff890 d __setup_set_debug_rodata
> ffffffff838b4b18 d __setup_str_set_debug_rodata
> ffffffff82200000 D __start_rodata
>
> Regards
> Alex

Found the reason why all symbols starting with '.' are dropped for s390x

/*
 *  Accept or reject a symbol from the kernel namelist.
 */
static int
s390x_verify_symbol(const char *name, ulong value, char type)
{
        int i;

...

        /* throw away all symbols containing a '.' */
        for(i = 0; i < strlen(name);i++){
                if(name[i] == '.')                    <-------------- !!!
                        return FALSE;
        }

        return TRUE;
}


But i have no idea why. Anybody familiar with this ?
 
I guess that it is to filter out some duplicated or unneeded symbols in crash-utility, especially for the old kernel. No more changelogs.

Thanks.
Lianbo
 
Thanks
Regards
Alex