Re: [Xen-devel] [PATCH v3 1/9] livepatch: Clear .bss when payload is reverted

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.08.16 at 23:52, <konrad.wilk@xxxxxxxxxx> wrote:
> @@ -374,7 +376,18 @@ static int move_payload(struct payload *payload, struct 
> livepatch_elf *elf)
>                          elf->name, elf->sec[i].name, elf->sec[i].load_addr);
>              }
>              else
> -                memset(elf->sec[i].load_addr, 0, elf->sec[i].sec->sh_size);
> +            {
> +                /* We expect only one BSS. */
> +                if ( payload->bss )
> +                {
> +                    rc = -EINVAL;

-EOPNOTSUPP according to e.g. the only- one-symbol-table code.

> +                    goto out;
> +                }
> +                payload->bss = elf->sec[i].load_addr;
> +                payload->bss_size = elf->sec[i].sec->sh_size;
> +
> +                memset(payload->bss, 0, payload->bss_size);
> +            }
>          }
>      }
>  
> @@ -1034,6 +1047,9 @@ static int revert_payload(struct payload *data)
>      list_del_rcu(&data->applied_list);
>      unregister_virtual_region(&data->region);
>  
> +    /* And clear the BSS for subsequent operation. */
> +    memset(data->bss, 0, data->bss_size);

Instead of doing it in two places, how about moving this into
apply_payload()?

Jan


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