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From:   Alexander Aring <aahringo@redhat.com>
Date:   Fri, 7 Apr 2023 18:20:32 -0400
Message-ID: <CAK-6q+gpRPxquCSCfPB+9Ym+1PTu9Z+qzC+PHj_K94nSGUbTWA@mail.gmail.com>
Subject: Re: [PATCH] ieee802154: hwsim: Fix possible memory leaks
To:     Chen Aotian <chenaotian2@163.com>
Cc:     alex.aring@gmail.com, stefan@datenfreihafen.org,
        miquel.raynal@bootlin.com, 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, stable@vger.kernelorg
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Hi,

On Fri, Apr 7, 2023 at 5:55=E2=80=AFAM Chen Aotian <chenaotian2@163.com> wr=
ote:
>
> After replacing e->info, it is necessary to free the old einfo.
>
> Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb")
> Signed-off-by: Chen Aotian <chenaotian2@163.com>
> ---
>  drivers/net/ieee802154/mac802154_hwsim.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> 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);

nitpick rcu_replace_pointer() can be used here.*

- Alex