On Tue, Sep 2, 2014, at 23:40, Eric Dumazet wrote:
> On Tue, 2014-09-02 at 14:31 -0700, Alexei Starovoitov wrote:
>
> > > +static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
> > > +{
> > > + set_memory_rw((unsigned long)fp, fp->pages);
> >
> > why rw is needed?
> > since fp is allocated with vmalloc, vfree doesn't need
> > to touch the pages to free them, no?
>
> That assumes that vmalloc() do not have any debugging features, like
> poisoning content before freeing, to catch some use after free.
>
> Lets be clean and safe, and give back same memory permission we had
> after vmalloc()
Yes, I agree. I just went down the kmemleak codepaths and we certainly
don't want to cause issues in there if the implementation changes one
day.
Bye,
Hannes
--
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/
