From: Rusty Russell Date: Tue, 20 Jan 2015 09:07:04 +1030 Subject: [PATCH] module_arch_freeing_init(): new hook for archs before module->module_init freed. Archs have been abusing module_free() to clean up their arch-specific allocations. Since module_free() is also (ab)used by BPF and trace code, let's keep it to simple allocations, and provide a hook called before that. This means that avr32, ia64, parisc and s390 no longer need to implement their own module_free() at all. avr32 doesn't need module_finalize() either. Signed-off-by: Rusty Russell Cc: Chris Metcalf Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Tony Luck Cc: Fenghua Yu Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: linux-kernel@vger.kernel.org Cc: linux-ia64@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linux-s390@vger.kernel.org Origin: backport, https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d453cded05ee219b77815ea194dc36efa5398bca --- arch/avr32/kernel/module.c | 13 +------------ arch/ia64/kernel/module.c | 6 ++---- arch/parisc/kernel/module.c | 6 +----- arch/s390/kernel/module.c | 10 +++------- arch/tile/kernel/module.c | 2 +- include/linux/moduleloader.h | 2 ++ kernel/module.c | 7 +++++++ 7 files changed, 17 insertions(+), 29 deletions(-) --- a/arch/avr32/kernel/module.c +++ b/arch/avr32/kernel/module.c @@ -19,12 +19,10 @@ #include #include -void module_free(struct module *mod, void *module_region) +void module_arch_freeing_init(struct module *mod) { vfree(mod->arch.syminfo); mod->arch.syminfo = NULL; - - vfree(module_region); } static inline int check_rela(Elf32_Rela *rela, struct module *module, @@ -291,12 +289,3 @@ int apply_relocate_add(Elf32_Shdr *sechd return ret; } - -int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, - struct module *module) -{ - vfree(module->arch.syminfo); - module->arch.syminfo = NULL; - - return 0; -} --- a/arch/ia64/kernel/module.c +++ b/arch/ia64/kernel/module.c @@ -305,14 +305,12 @@ plt_target (struct plt_entry *plt) #endif /* !USE_BRL */ void -module_free (struct module *mod, void *module_region) +module_arch_freeing_init (struct module *mod) { - if (mod && mod->arch.init_unw_table && - module_region == mod->module_init) { + if (mod->arch.init_unw_table) { unw_remove_unwind_table(mod->arch.init_unw_table); mod->arch.init_unw_table = NULL; } - vfree(module_region); } /* Have we already seen one of these relocations? */ --- a/arch/parisc/kernel/module.c +++ b/arch/parisc/kernel/module.c @@ -298,14 +298,10 @@ static inline unsigned long count_stubs( } #endif - -/* Free memory returned from module_alloc */ -void module_free(struct module *mod, void *module_region) +void module_arch_freeing_init(struct module *mod) { kfree(mod->arch.section); mod->arch.section = NULL; - - vfree(module_region); } /* Additional bytes needed in front of individual sections */ --- a/arch/s390/kernel/module.c +++ b/arch/s390/kernel/module.c @@ -55,14 +55,10 @@ void *module_alloc(unsigned long size) } #endif -/* Free memory returned from module_alloc */ -void module_free(struct module *mod, void *module_region) +void module_arch_freeing_init(struct module *mod) { - if (mod) { - vfree(mod->arch.syminfo); - mod->arch.syminfo = NULL; - } - vfree(module_region); + vfree(mod->arch.syminfo); + mod->arch.syminfo = NULL; } static void check_rela(Elf_Rela *rela, struct module *me) --- a/arch/tile/kernel/module.c +++ b/arch/tile/kernel/module.c @@ -83,7 +83,7 @@ void module_free(struct module *mod, voi 0, 0, 0, NULL, NULL, 0); /* - * FIXME: If module_region == mod->module_init, trim exception + * FIXME: Add module_arch_freeing_init to trim exception * table entries. */ } --- a/include/linux/moduleloader.h +++ b/include/linux/moduleloader.h @@ -82,4 +82,6 @@ int module_finalize(const Elf_Ehdr *hdr, /* Any cleanup needed when module leaves. */ void module_arch_cleanup(struct module *mod); +/* Any cleanup before freeing mod->module_init */ +void module_arch_freeing_init(struct module *mod); #endif --- a/kernel/module.c +++ b/kernel/module.c @@ -1840,6 +1840,10 @@ void __weak module_arch_cleanup(struct m { } +void __weak module_arch_freeing_init(struct module *mod) +{ +} + /* Free a module, remove from lists, etc. */ static void free_module(struct module *mod) { @@ -1872,6 +1876,7 @@ static void free_module(struct module *m /* This may be NULL, but that's OK */ unset_module_init_ro_nx(mod); + module_arch_freeing_init(mod); module_free(mod, mod->module_init); kfree(mod->args); percpu_modfree(mod); @@ -2983,6 +2988,7 @@ static struct module *layout_and_allocat static void module_deallocate(struct module *mod, struct load_info *info) { percpu_modfree(mod); + module_arch_freeing_init(mod); module_free(mod, mod->module_init); module_free(mod, mod->module_core); } @@ -3105,6 +3111,7 @@ static int do_init_module(struct module rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms); #endif unset_module_init_ro_nx(mod); + module_arch_freeing_init(mod); module_free(mod, mod->module_init); mod->module_init = NULL; mod->init_size = 0;