Messages in this thread | | | Date | Sat, 30 Apr 2022 14:38:14 +0100 | From | Mauro Carvalho Chehab <> | Subject | Re: [PATCH v2 1/2] module: update dependencies at try_module_get() |
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Em Sat, 30 Apr 2022 14:04:59 +0200 Greg KH <gregkh@linuxfoundation.org> escreveu:
> On Sat, Apr 30, 2022 at 11:30:58AM +0100, Mauro Carvalho Chehab wrote:
> Did you run checkpatch on this? Please do :) > > > + > > + if (mod == this) > > + return 0; > > How can this happen? > When people mistakenly call try_module_get(THIS_MODULE)?
Yes. There are lots of place where this is happening:
$ git grep try_module_get\(THIS_MODULE|wc -l 82
> We should > throw up a big warning when that happens anyway as that's always wrong. > > But that's a different issue from this change, sorry for the noise.
It sounds very weird to use try_module_get(THIS_MODULE).
We could add a WARN_ON() there - or something similar - but I would do it on a separate patch.
> > > + > > + mutex_lock(&module_mutex); > > + > > + ret = ref_module(this, mod); > > + > > +#ifdef CONFIG_MODULE_UNLOAD > > + if (ret) > > + goto ret; > > + > > + ret = sysfs_create_link(mod->holders_dir, > > + &this->mkobj.kobj, this->name); > > Meta comment, why do we only create links if we can unload things?
Good question. I don't know for certain. This is the already existing pattern at add_usage_links() - see kernel/module/sysfs.c.
Also, lsmod uses sysfs links when showing dependencies.
Regards, Mauro
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