On 28.10.19 16:27, Ilya Leoshkevich wrote:
> gcc's -freorder-blocks-and-partition option makes it group frequently
> and infrequently used code in .text.hot and .text.unlikely sections
> respectively. At least when building modules on s390, this option is
> used by default.
>
> gdb assumes that all code is located in .text section, and that .text
> section is located at module load address. With such modules this is no
> longer the case: there is code in .text.hot and .text.unlikely, and
> either of them might precede .text.
>
> Fix by explicitly telling gdb the addresses of code sections.
>
> It might be tempting to do this for all sections, not only the ones in
> the white list. Unfortunately, gdb appears to have an issue, when telling
> it about e.g. loadable .note.gnu.build-id section causes it to think that
> non-loadable .note.Linux section is loaded at address 0, which in turn
> causes NULL pointers to be resolved to bogus symbols. So keep using the
> white list approach for the time being.
Did you report this to gdb?
>
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
> ---
> scripts/gdb/linux/symbols.py | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/gdb/linux/symbols.py b/scripts/gdb/linux/symbols.py
> index 7b7c2fafbc68..be984aa29b75 100644
> --- a/scripts/gdb/linux/symbols.py
> +++ b/scripts/gdb/linux/symbols.py
> @@ -99,7 +99,8 @@ lx-symbols command."""
> attrs[n]['name'].string(): attrs[n]['address']
> for n in range(int(sect_attrs['nsections']))}
> args = []
> - for section_name in [".data", ".data..read_mostly", ".rodata", ".bss"]:
> + for section_name in [".data", ".data..read_mostly", ".rodata", ".bss",
> + ".text", ".text.hot", ".text.unlikely"]:
> address = section_name_to_address.get(section_name)
> if address:
> args.append(" -s {name} {addr}".format(
>
Reviewed-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
