Re: [PATCH net] ipv6: Fix cleanup ordering on inet6_init() error path

[Ben Hutchings <ben.hutchings@codethink.co.uk>]

On Wed, 2018-01-10 at 14:25 -0800, Cong Wang wrote:
> On Tue, Jan 9, 2018 at 10:21 AM, Ben Hutchings
> <ben.hutchings@codethink.co.uk> wrote:
> > Commit 15e668070a64 reordered the initialisation in inet6_init() to
> > fix a crash on an error path further down the call stack.  It also
> > reordered cleanup on the error path in inet6_init(), but the result
> > is not the reverse of the initialisation order.  This presumably
> > can result in a resource leak or crash in some error
> > cases.  Reorder
> > cleanup again to fix this.
> 
> Can you be specific on what resource we leak here?

If icmpv6_init() fails, after ip6_mr_init(), then ip6_mr_cleanup() is
not called.

Also, if ip6_mr_init() fails, we don't unregister inet6_net_ops.  I
think that will result in a crash - immediately if ipv6 is a module,
otherwise when the next net namespace is created.

> Also, it looks like you not just revert the order changed in commit
> 15e668070a64, but also you move  icmpv6_cleanup() even earlier.

So should I add another Fixes: there?

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.