Messages in this thread | | | Date | Fri, 13 Nov 2015 21:09:50 -0500 | From | Jessica Yu <> | Subject | Re: module: save load_info for livepatch modules |
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+++ Miroslav Benes [13/11/15 13:56 +0100]: >On Fri, 13 Nov 2015, Miroslav Benes wrote: > >> I agree this seems like the best approach. So if we preserve >> mod_arch_syminfo (in case of s390) we should free it not in >> module_finalize, but somewhere in free_module... where >> module_arch_cleanup() is called... and also module_arch_freeing_init() is >> called there too. And what you find there for s390 is >> >> vfree(mod->arch.syminfo); >> mod->arch.syminfo = NULL; >> >> Well, it does nothing here, because mod->arch.syminfo is already NULL. It >> was freed in module_finalize. So we can even remove this code from >> module_finalize and all should be fine. At least for s390. > >Which is not true because module_arch_freeing_init is also called from >do_init_module, called from load_module. So we should move it to >module_arch_cleanup. > >That code is like a maze without Ariadne's thread.
Heh, I agree with that sentiment.
I am slightly confused about the s390 code, and whether the authors originally intended for that double vfree() to happen in both module_finalize() and module_arch_freeing_init() (called from do_init_module). Seems like a mistake. If module load succeeds, do_init_module calls module_arch_freeing_init(). And if load_module fails halfway through, both module_deallocate() and free_module() will also call module_arch_freeing_init(). I feel like that vfree should only happen once in module_arch_freeing_init() and not in module_finalize(). If we can remove the double vfree() code from module_finalize(), we can copy the mod_arch_specific safely before the call to do_init_module().
Jessica
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