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

Herbert Xu
2020-03-23T06:29:46Z

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?

Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt