Messages in this thread Patch in this message | | | Date | Wed, 16 Dec 2015 18:48:28 -0500 | From | Jessica Yu <> | Subject | Re: module: s390: keep mod_arch_specific for livepatch modules |
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+++ Miroslav Benes [16/12/15 13:02 +0100]: >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@redhat.com> >> --- >> 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.
Gah. Good catch. How about we add an additional check to see if mod->state is MODULE_STATE_LIVE? If so, we can return. This means we're coming from do_init_module(). If module_arch_freeing_init() was called and the module was in a state other than MODULE_STATE_LIVE (UNFORMED, GOING, COMING), we know we need to free. Think that would work?
Jessica
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