lkml.org 
[lkml]   [2017]   [Sep]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: Re: [PATCH] net/packet: fix race condition between fanout_add and __unregister_prot_hook
On Tue, Sep 19, 2017 at 12:09 PM, Willem de Bruijn
<willemdebruijn.kernel@gmail.com> wrote:
> On Tue, Sep 19, 2017 at 3:21 AM, Nixiaoming <nixiaoming@huawei.com> wrote:
>> On Fri, Sep 15, 2017 at 10:46 AM, Willem de Bruijn
>>
>> <willemdebruijn.kernel@gmail.com> wrote:
>>
>>>
>>
>>> In case of failure we also need to unlink and free match. I
>>
>>> sent the following:
>>
>>>
>>
>>> http://patchwork.ozlabs.org/patch/813945/
>>
>>
>>
>> + spin_lock(&po->bind_lock);
>>
>> + if (po->running &&
>>
>> + match->type == type &&
>>
>> match->prot_hook.type == po->prot_hook.type &&
>>
>> match->prot_hook.dev == po->prot_hook.dev) {
>>
>> err = -ENOSPC;
>>
>> @@ -1761,6 +1760,13 @@ static int fanout_add(struct sock *sk, u16 id, u16
>> type_flags)
>>
>> err = 0;
>>
>> }
>>
>> }
>>
>> + spin_unlock(&po->bind_lock);
>>
>> +
>>
>> + if (err && !refcount_read(&match->sk_ref)) {
>>
>> + list_del(&match->list);
>>
>> + kfree(match);
>>
>> + }
>>
>>
>>
>>
>>
>> In the function fanout_add add spin_lock to protect po-> running and po->
>> fanout,
>>
>> then whether it should be in the function fanout_release also add spin_lock
>> protection ?
>
> po->bind_lock is held when registering and unregistering the
> protocol hook. fanout_release does access po->running or
> prot_hook.

whoops. does *not* access.

\
 
 \ /
  Last update: 2017-09-19 18:14    [W:0.052 / U:0.588 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site