Messages in this thread | | | From | Menglong Dong <> | Date | Wed, 4 Nov 2020 22:14:35 +0800 | Subject | Re: [PATCH] net: bridge: disable multicast while delete bridge |
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Dear Nik,
On Wed, Nov 4, 2020 at 12:26 AM Nikolay Aleksandrov <nikolay@nvidia.com> wrote: > > On Mon, 2020-11-02 at 22:38 +0800, Menglong Dong wrote: > > From: Menglong Dong <dong.menglong@zte.com.cn> > > > > This commit seems make no sense, as bridge is destroyed when > > br_multicast_dev_del is called. > > > > In commit b1b9d366028f > > ("bridge: move bridge multicast cleanup to ndo_uninit"), Xin Long > > fixed the use-after-free panic in br_multicast_group_expired by > > moving br_multicast_dev_del to ndo_uninit. However, that patch is > > not applied to 4.4.X, and the bug exists. > > > > Fix that bug by disabling multicast in br_multicast_dev_del for > > 4.4.X, and there is no harm for other branches. > > > > Signed-off-by: Menglong Dong <dong.menglong@zte.com.cn> > > --- > > net/bridge/br_multicast.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c > > index eae898c3cff7..9992fdff2951 100644 > > --- a/net/bridge/br_multicast.c > > +++ b/net/bridge/br_multicast.c > > @@ -3369,6 +3369,7 @@ void br_multicast_dev_del(struct net_bridge *br) > > hlist_for_each_entry_safe(mp, tmp, &br->mdb_list, mdb_node) > > br_multicast_del_mdb_entry(mp); > > hlist_move_list(&br->mcast_gc_list, &deleted_head); > > + br_opt_toggle(br, BROPT_MULTICAST_ENABLED, false); > > spin_unlock_bh(&br->multicast_lock); > > > > br_multicast_gc(&deleted_head); > > This doesn't make any sense. It doesn't fix anything. > If 4.4 has a problem then the relevant patches should get backported to it. > We don't add random changes to fix older releases. > > Cheers, > Nik > > Nacked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Thanks for your patient explanation, and I see it now~
Cheers, Menglong Dong
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