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Date:   Fri, 7 Apr 2023 10:01:48 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Chen Aotian <chenaotian2@163.com>
Cc:     alex.aring@gmail.com, stefan@datenfreihafen.org,
        davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, linux-wpan@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ieee802154: hwsim: Fix possible memory leaks
Message-ID: <20230407100148.16a0531e@xps-13>
In-Reply-To: <20230407012626.45500-1-chenaotian2@163.com>
References: <20230407012626.45500-1-chenaotian2@163.com>
Organization: Bootlin
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Hi Chen,

chenaotian2@163.com wrote on Fri,  7 Apr 2023 09:26:26 +0800:

> After replacing e->info, it is necessary to free the old einfo.
>=20
> Signed-off-by: Chen Aotian <chenaotian2@163.com>
> ---
>  drivers/net/ieee802154/mac802154_hwsim.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>=20
> diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee8=
02154/mac802154_hwsim.c
> index 8445c2189..6e7e10b17 100644
> --- a/drivers/net/ieee802154/mac802154_hwsim.c
> +++ b/drivers/net/ieee802154/mac802154_hwsim.c
> @@ -685,7 +685,7 @@ static int hwsim_del_edge_nl(struct sk_buff *msg, str=
uct genl_info *info)
>  static int hwsim_set_edge_lqi(struct sk_buff *msg, struct genl_info *inf=
o)
>  {
>  	struct nlattr *edge_attrs[MAC802154_HWSIM_EDGE_ATTR_MAX + 1];
> -	struct hwsim_edge_info *einfo;
> +	struct hwsim_edge_info *einfo, *einfo_old;
>  	struct hwsim_phy *phy_v0;
>  	struct hwsim_edge *e;
>  	u32 v0, v1;
> @@ -723,8 +723,10 @@ static int hwsim_set_edge_lqi(struct sk_buff *msg, s=
truct genl_info *info)
>  	list_for_each_entry_rcu(e, &phy_v0->edges, list) {
>  		if (e->endpoint->idx =3D=3D v1) {
>  			einfo->lqi =3D lqi;
> +			einfo_old =3D rcu_dereference(e->info);
>  			rcu_assign_pointer(e->info, einfo);
>  			rcu_read_unlock();
> +			kfree_rcu(einfo_old, rcu);
>  			mutex_unlock(&hwsim_phys_lock);
>  			return 0;
>  		}

I'm not an RCU expert but the fix LGTM.

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

What about adding:

Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb")
Cc: stable@vger.kernelorg

Thanks,
Miqu=C3=A8l