Re: [PATCH net-next] tcp/dccp: fix inet_reuseport_add_sock()

[David Miller]

From: Eric Dumazet 
Date: Wed, 06 Apr 2016 22:07:34 -0700

> From: Eric Dumazet 
> 
> David Ahern reported panics in __inet_hash() caused by my recent commit.
> 
> The reason is inet_reuseport_add_sock() was still using
> sk_nulls_for_each_rcu() instead of sk_for_each_rcu().
> SO_REUSEPORT enabled listeners were causing an instant crash.
> 
> While chasing this bug, I found that I forgot to clear SOCK_RCU_FREE
> flag, as it is inherited from the parent at clone time.
> 
> Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under 
> synflood")
> Signed-off-by: Eric Dumazet 
> Reported-by: David Ahern 

Applied, thanks Eric.

Re: [PATCH net-next] tcp/dccp: fix inet_reuseport_add_sock()

[David Ahern]

On 4/6/16 11:07 PM, Eric Dumazet wrote:

From: Eric Dumazet 

David Ahern reported panics in __inet_hash() caused by my recent commit.

The reason is inet_reuseport_add_sock() was still using
sk_nulls_for_each_rcu() instead of sk_for_each_rcu().
SO_REUSEPORT enabled listeners were causing an instant crash.

While chasing this bug, I found that I forgot to clear SOCK_RCU_FREE
flag, as it is inherited from the parent at clone time.

Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
Signed-off-by: Eric Dumazet 
Reported-by: David Ahern 
---


Fixed the problem I as hiting.

Tested-by: David Ahern 

[PATCH net-next] tcp/dccp: fix inet_reuseport_add_sock()

[Eric Dumazet]

From: Eric Dumazet 

David Ahern reported panics in __inet_hash() caused by my recent commit.

The reason is inet_reuseport_add_sock() was still using
sk_nulls_for_each_rcu() instead of sk_for_each_rcu().
SO_REUSEPORT enabled listeners were causing an instant crash.

While chasing this bug, I found that I forgot to clear SOCK_RCU_FREE
flag, as it is inherited from the parent at clone time.

Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood")
Signed-off-by: Eric Dumazet 
Reported-by: David Ahern 
---
 net/ipv4/inet_connection_sock.c |3 +++
 net/ipv4/inet_hashtables.c  |3 +--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index bc5196ea1bdf..ab69da2d2a77 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -661,6 +661,9 @@ struct sock *inet_csk_clone_lock(const struct sock *sk,
inet_sk(newsk)->inet_sport = htons(inet_rsk(req)->ir_num);
newsk->sk_write_space = sk_stream_write_space;
 
+   /* listeners have SOCK_RCU_FREE, not the children */
+   sock_reset_flag(newsk, SOCK_RCU_FREE);
+
newsk->sk_mark = inet_rsk(req)->ir_mark;
atomic64_set(>sk_cookie,
 atomic64_read(_rsk(req)->ir_cookie));
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 98ba03b6f87d..fcadb670f50b 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -439,10 +439,9 @@ static int inet_reuseport_add_sock(struct sock *sk,
 bool match_wildcard))
 {
struct sock *sk2;
-   struct hlist_nulls_node *node;
kuid_t uid = sock_i_uid(sk);
 
-   sk_nulls_for_each_rcu(sk2, node, >head) {
+   sk_for_each_rcu(sk2, >head) {
if (sk2 != sk &&
sk2->sk_family == sk->sk_family &&
ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&