Re: [RFC PATCH v2 3/6] module: s390: keep mod_arch_specific for livepatch modules
From: Miroslav Benes <mbenes@suse.cz>
Date: 2015-12-16 12:02:37
Also in:
linux-s390, lkml
On Mon, 30 Nov 2015, Jessica Yu wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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
quoted hunk ↗ jump to hunk
@@ -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