Re: [PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher()

[David Miller]

From: Eric Dumazet 
Date: Thu, 02 Nov 2017 11:53:04 -0700

> From: Eric Dumazet 
> 
> 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 

Applied.

Re: [PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher()

[Christoph Paasch]

On 02/11/17 - 11:53:04, Eric Dumazet wrote:
> From: Eric Dumazet 
> 
> 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 
> Cc: Yuchung Cheng 
> Cc: Christoph Paasch 
> ---
>  net/ipv4/tcp_fastopen.c |8 +++-
>  1 file changed, 3 insertions(+), 5 deletions(-)

Reviewed-by: Christoph Paasch 

[PATCH net-next] tcp: fix a lockdep issue in tcp_fastopen_reset_cipher()

[Eric Dumazet]

From: Eric Dumazet 

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 
Cc: Yuchung Cheng 
Cc: Christoph Paasch 
---
 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(>ipv4.tcp_fastopen_ctx_lock);
if (sk) {
q = _csk(sk)->icsk_accept_queue.fastopenq;
-   spin_lock_bh(>lock);
octx = rcu_dereference_protected(q->ctx,
-lockdep_is_held(>lock));
+   lockdep_is_held(>ipv4.tcp_fastopen_ctx_lock));
rcu_assign_pointer(q->ctx, ctx);
-   spin_unlock_bh(>lock);
} else {
-   spin_lock(>ipv4.tcp_fastopen_ctx_lock);
octx = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx,
lockdep_is_held(>ipv4.tcp_fastopen_ctx_lock));
rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, ctx);
-   spin_unlock(>ipv4.tcp_fastopen_ctx_lock);
}
+   spin_unlock(>ipv4.tcp_fastopen_ctx_lock);
 
if (octx)
call_rcu(>rcu, tcp_fastopen_ctx_free);