Re: [PATCH v2] xfrm: policy: Fix doulbe free in xfrm_policy_timer

Yuehaibing
2020-03-23T07:04:11Z

On 2020/3/23 14:29, Herbert Xu wrote:
> On Mon, Mar 23, 2020 at 09:41:55AM +0800, YueHaibing wrote:
>>
>> diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
>> index dbda08ec566e..ae0689174bbf 100644
>> --- a/net/xfrm/xfrm_policy.c
>> +++ b/net/xfrm/xfrm_policy.c
>> @@ -434,6 +434,7 @@ EXPORT_SYMBOL(xfrm_policy_destroy);
>>
>> static void xfrm_policy_kill(struct xfrm_policy *policy)
>> {
>> + write_lock_bh(&policy->lock);
>> policy->walk.dead = 1;
>>
>> atomic_inc(&policy->genid);
>> @@ -445,6 +446,7 @@ static void xfrm_policy_kill(struct xfrm_policy *policy)
>> if (del_timer(&policy->timer))
>> xfrm_pol_put(policy);
>>
>> + write_unlock_bh(&policy->lock);
>
> Why did you expand the critical section? Can't you just undo the
> patch in xfrm_policy_kill?

Indeed, the critical section should not be expanded, thanks!

>
> Cheers,
>