On Fri, 13 Nov 2015, Jessica Yu wrote: > +++ 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().
It seems like the authors are aware of this. At least the authors of general module code :). See comment in free_module() /* This may be NULL, but that's OK */ It is ok, because vfree checks if the pointer is NULL. > 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(). Yes, I think so. Miroslav -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
