On Thu, Jan 02, 2020 at 10:28:44PM +0100, Michal Kubecek wrote:
> From: Eric Dumazet <edumazet@xxxxxxxxxx>
>
> [ Upstream commit 8dbd76e79a16b45b2ccb01d2f2e08dbf64e71e40 ]
>
> Michal Kubecek and Firo Yang did a very nice analysis of crashes
> happening in __inet_lookup_established().
>
> Since a TCP socket can go from TCP_ESTABLISH to TCP_LISTEN
> (via a close()/socket()/listen() cycle) without a RCU grace period,
> I should not have changed listeners linkage in their hash table.
>
> They must use the nulls protocol (Documentation/RCU/rculist_nulls.txt),
> so that a lookup can detect a socket in a hash list was moved in
> another one.
>
> Since we added code in commit d296ba60d8e2 ("soreuseport: Resolve
> merge conflict for v4/v6 ordering fix"), we have to add
> hlist_nulls_add_tail_rcu() helper.
>
> stable-4.19: we also need to update code in __inet_lookup_listener() and
> inet6_lookup_listener() which has been removed in 5.0-rc1.
>
> Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
> Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> Reported-by: Michal Kubecek <mkubecek@xxxxxxx>
> Reported-by: Firo Yang <firo.yang@xxxxxxxx>
> Reviewed-by: Michal Kubecek <mkubecek@xxxxxxx>
> Link: https://lore.kernel.org/netdev/20191120083919.GH27852@xxxxxxxxxxxxxxx/
> Signed-off-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
> Signed-off-by: Michal Kubecek <mkubecek@xxxxxxx>
Thanks for the updated patches, all now queued up.
greg k-h
