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From:   Chen Aotian <chenaotian2@163.com>
To:     aahringo@redhat.com, miquel.raynal@bootlin.com
Cc:     alex.aring@gmail.com, chenaotian2@163.com, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, linux-kernel@vger.kernel.org,
        linux-wpan@vger.kernel.org, netdev@vger.kernel.org,
        pabeni@redhat.com, stable@vger.kernel.org,
        stefan@datenfreihafen.org
Subject: Re: [PATCH] ieee802154: hwsim: Fix possible memory leaks
Date:   Sat,  8 Apr 2023 14:43:31 +0800
Message-Id: <20230408064331.46176-1-chenaotian2@163.com>
In-Reply-To: <CAK-6q+gpRPxquCSCfPB+9Ym+1PTu9Z+qzC+PHj_K94nSGUbTWA@mail.gmail.com>
References: <CAK-6q+gpRPxquCSCfPB+9Ym+1PTu9Z+qzC+PHj_K94nSGUbTWA@mail.gmail.com>
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Fri, 7 Apr 2023 18:20:32 -0400 Alexander Aring <aahringo@redhat.com> wrote:
>
> On Fri, Apr 7, 2023 at 5:55 AM Chen Aotian <chenaotian2@163.com> wrote:
> >
> > 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/ieee802154/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, struct genl_info *info)
> >  static int hwsim_set_edge_lqi(struct sk_buff *msg, struct genl_info *info)
> >  {
> >         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, struct genl_info *info)
> >         list_for_each_entry_rcu(e, &phy_v0->edges, list) {
> >                 if (e->endpoint->idx == v1) {
> >                         einfo->lqi = lqi;
> > +                       einfo_old = rcu_dereference(e->info);
> >                         rcu_assign_pointer(e->info, einfo);
> 
> nitpick rcu_replace_pointer() can be used here.*

Thank you for your suggestion, Alex. BTW, thanks for Miquèl's patient 
guidance too, I just started trying to submit patches to the kernel, 
I will do batter.

Thanks,
Chen