On Thu, Jan 02, 2020 at 10:28:44PM +0100, Michal Kubecek wrote:
From: Eric Dumazet edumazet@google.com
[ 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@google.com Reported-by: Michal Kubecek mkubecek@suse.cz Reported-by: Firo Yang firo.yang@suse.com Reviewed-by: Michal Kubecek mkubecek@suse.cz Link: https://lore.kernel.org/netdev/20191120083919.GH27852@unicorn.suse.cz/ Signed-off-by: Jakub Kicinski jakub.kicinski@netronome.com Signed-off-by: Michal Kubecek mkubecek@suse.cz
Thanks for the updated patches, all now queued up.
greg k-h