* [PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher()
@ 2017-11-02 18:53 Eric Dumazet
2017-11-02 19:55 ` Christoph Paasch
2017-11-03 6:54 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Eric Dumazet @ 2017-11-02 18:53 UTC (permalink / raw)
To: David Miller; +Cc: netdev, Yuchung Cheng, Christoph Paasch
From: Eric Dumazet <edumazet@google.com>
icsk_accept_queue.fastopenq.lock is only fully initialized at listen()
time.
LOCKDEP is not happy if we attempt a spin_lock_bh() on it, because
of missing annotation. (Although kernel runs just fine)
Lets use net->ipv4.tcp_fastopen_ctx_lock to protect ctx access.
Fixes: 1fba70e5b6be ("tcp: socket option to set TCP fast open key")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Christoph Paasch <cpaasch@apple.com>
---
net/ipv4/tcp_fastopen.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index e0a4b56644aa0f8ccd384644fde7e4841da29d3f..91762be58accaed7d8974e723b580fb3d7922fca 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -92,20 +92,18 @@ error: kfree(ctx);
memcpy(ctx->key, key, len);
+ spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
if (sk) {
q = &inet_csk(sk)->icsk_accept_queue.fastopenq;
- spin_lock_bh(&q->lock);
octx = rcu_dereference_protected(q->ctx,
- lockdep_is_held(&q->lock));
+ lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
rcu_assign_pointer(q->ctx, ctx);
- spin_unlock_bh(&q->lock);
} else {
- spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
octx = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx,
lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, ctx);
- spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock);
}
+ spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock);
if (octx)
call_rcu(&octx->rcu, tcp_fastopen_ctx_free);
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher()
2017-11-02 18:53 [PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher() Eric Dumazet
@ 2017-11-02 19:55 ` Christoph Paasch
2017-11-03 6:54 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Christoph Paasch @ 2017-11-02 19:55 UTC (permalink / raw)
To: Eric Dumazet; +Cc: David Miller, netdev, Yuchung Cheng
On 02/11/17 - 11:53:04, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> icsk_accept_queue.fastopenq.lock is only fully initialized at listen()
> time.
>
> LOCKDEP is not happy if we attempt a spin_lock_bh() on it, because
> of missing annotation. (Although kernel runs just fine)
>
> Lets use net->ipv4.tcp_fastopen_ctx_lock to protect ctx access.
>
> Fixes: 1fba70e5b6be ("tcp: socket option to set TCP fast open key")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Yuchung Cheng <ycheng@google.com>
> Cc: Christoph Paasch <cpaasch@apple.com>
> ---
> net/ipv4/tcp_fastopen.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
Reviewed-by: Christoph Paasch <cpaasch@apple.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher()
2017-11-02 18:53 [PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher() Eric Dumazet
2017-11-02 19:55 ` Christoph Paasch
@ 2017-11-03 6:54 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2017-11-03 6:54 UTC (permalink / raw)
To: eric.dumazet; +Cc: netdev, ycheng, cpaasch
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 02 Nov 2017 11:53:04 -0700
> From: Eric Dumazet <edumazet@google.com>
>
> icsk_accept_queue.fastopenq.lock is only fully initialized at listen()
> time.
>
> LOCKDEP is not happy if we attempt a spin_lock_bh() on it, because
> of missing annotation. (Although kernel runs just fine)
>
> Lets use net->ipv4.tcp_fastopen_ctx_lock to protect ctx access.
>
> Fixes: 1fba70e5b6be ("tcp: socket option to set TCP fast open key")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-11-02 18:53 [PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher() Eric Dumazet
2017-11-02 19:55 ` Christoph Paasch
2017-11-03 6:54 ` David Miller
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