netdev - Re: [PATCH net] ipv6: Fix cleanup ordering on inet6

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Message-ID: <CAM_iQpXv16MwD22geJ2pyboOTfh2aStRR3-oUEsDD3QPxhhGoQ@mail.gmail.com>
Date:   Sat, 13 Jan 2018 09:38:58 -0800
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Ben Hutchings <ben.hutchings@...ethink.co.uk>
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: Re: [PATCH net] ipv6: Fix cleanup ordering on inet6_init() error path

On Thu, Jan 11, 2018 at 8:48 AM, Ben Hutchings
<ben.hutchings@...ethink.co.uk> wrote:
> 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@...ethink.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.

Ah, I somehow misread the patch. It looks good.

>
>> 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?

No, I think it is okay.