On Mon, 30 Nov 2015, Jessica Yu wrote:
> Livepatch needs to utilize the symbol information contained in the
> mod_arch_specific struct in order to be able to call the s390
> apply_relocate_add() function to apply relocations. Remove the redundant
> vfree() in module_finalize() since module_arch_freeing_init() (which also frees
> said structures) is called in do_init_module(). Keep a reference to syminfo if
> the module is a livepatch module and free the structures in
> module_arch_cleanup(). If the module isn't a livepatch module, we free the
> structures in module_arch_freeing_init() as usual.
>
> Signed-off-by: Jessica Yu <jeyu@xxxxxxxxxx>
> ---
> arch/s390/kernel/module.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
> index 0c1a679..17a1979 100644
> --- a/arch/s390/kernel/module.c
> +++ b/arch/s390/kernel/module.c
> @@ -51,6 +51,9 @@ void *module_alloc(unsigned long size)
>
> void module_arch_freeing_init(struct module *mod)
> {
> + if (mod->klp)
> + return;
> +
> vfree(mod->arch.syminfo);
> mod->arch.syminfo = NULL;
> }
Hm, this is problematic. module_arch_freeing_init() is called from
module_deallocate() and this is called in the error path in load_module().
So if there was an error during load_module() of livepatch module which
led to free_modinfo label or behind mod->arch.syminfo would not be freed
at all. module_arch_cleanup() is called earlier under
free_arch_cleanup.
Miroslav
> @@ -420,12 +423,18 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
> return 0;
> }
>
> +void module_arch_cleanup(struct module *mod)
> +{
> + if (mod->klp) {
> + vfree(mod->arch.syminfo);
> + mod->arch.syminfo = NULL;
> + }
> +}
> +
> int module_finalize(const Elf_Ehdr *hdr,
> const Elf_Shdr *sechdrs,
> struct module *me)
> {
> jump_label_apply_nops(me);
> - vfree(me->arch.syminfo);
> - me->arch.syminfo = NULL;
> return 0;
> }
> --
> 2.4.3
>
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