FAILED: patch "[PATCH] mptcp: avoid duplicated SUB_CLOSED events" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] mptcp: avoid duplicated SUB_CLOSED events" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x d82809b6c5f2676b382f77a5cbeb1a5d91ed2235
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024083026-snooper-unbundle-373f@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

d82809b6c5f2 ("mptcp: avoid duplicated SUB_CLOSED events")
a7cfe7766370 ("mptcp: fix data races on local_id")
84c531f54ad9 ("mptcp: userspace pm send RM_ADDR for ID 0")
f1f26512a9bf ("mptcp: use plain bool instead of custom binary enum")
1e07938e29c5 ("net: mptcp: rename netlink handlers to mptcp_pm_nl_<blah>_{doit,dumpit}")
1d0507f46843 ("net: mptcp: convert netlink from small_ops to ops")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d82809b6c5f2676b382f77a5cbeb1a5d91ed2235 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Wed, 28 Aug 2024 08:14:35 +0200
Subject: [PATCH] mptcp: avoid duplicated SUB_CLOSED events
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The initial subflow might have already been closed, but still in the
connection list. When the worker is instructed to close the subflows
that have been marked as closed, it might then try to close the initial
subflow again.

 A consequence of that is that the SUB_CLOSED event can be seen twice:

  # ip mptcp endpoint
  1.1.1.1 id 1 subflow dev eth0
  2.2.2.2 id 2 subflow dev eth1

  # ip mptcp monitor &
  [         CREATED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [     ESTABLISHED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [  SF_ESTABLISHED] remid=0 locid=2 saddr4=2.2.2.2 daddr4=9.9.9.9

  # ip mptcp endpoint delete id 1
  [       SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [       SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9

The first one is coming from mptcp_pm_nl_rm_subflow_received(), and the
second one from __mptcp_close_subflow().

To avoid doing the post-closed processing twice, the subflow is now
marked as closed the first time.

Note that it is not enough to check if we are dealing with the first
subflow and check its sk_state: the subflow might have been reset or
closed before calling mptcp_close_ssk().

Fixes: b911c97c7dc7 ("mptcp: add netlink event support")
Cc: stable@vger.kernel.org
Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index b571fba88a2f..37ebcb7640eb 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2508,6 +2508,12 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 		     struct mptcp_subflow_context *subflow)
 {
+	/* The first subflow can already be closed and still in the list */
+	if (subflow->close_event_done)
+		return;
+
+	subflow->close_event_done = true;
+
 	if (sk->sk_state == TCP_ESTABLISHED)
 		mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 240d7c2ea551..26eb898a202b 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -524,7 +524,8 @@ struct mptcp_subflow_context {
 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
 		valid_csum_seen : 1,        /* at least one csum validated */
 		is_mptfo : 1,	    /* subflow is doing TFO */
-		__unused : 10;
+		close_event_done : 1,       /* has done the post-closed part */
+		__unused : 9;
 	bool	data_avail;
 	bool	scheduled;
 	u32	remote_nonce;

[PATCH 6.6.y] mptcp: avoid duplicated SUB_CLOSED events

[Matthieu Baerts (NGI0)]

commit d82809b6c5f2676b382f77a5cbeb1a5d91ed2235 upstream.

The initial subflow might have already been closed, but still in the
connection list. When the worker is instructed to close the subflows
that have been marked as closed, it might then try to close the initial
subflow again.

 A consequence of that is that the SUB_CLOSED event can be seen twice:

  # ip mptcp endpoint
  1.1.1.1 id 1 subflow dev eth0
  2.2.2.2 id 2 subflow dev eth1

  # ip mptcp monitor &
  [         CREATED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [     ESTABLISHED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [  SF_ESTABLISHED] remid=0 locid=2 saddr4=2.2.2.2 daddr4=9.9.9.9

  # ip mptcp endpoint delete id 1
  [       SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
  [       SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9

The first one is coming from mptcp_pm_nl_rm_subflow_received(), and the
second one from __mptcp_close_subflow().

To avoid doing the post-closed processing twice, the subflow is now
marked as closed the first time.

Note that it is not enough to check if we are dealing with the first
subflow and check its sk_state: the subflow might have been reset or
closed before calling mptcp_close_ssk().

Fixes: b911c97c7dc7 ("mptcp: add netlink event support")
Cc: stable@vger.kernel.org
Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
[ Conflict in protocol.h due to commit f1f26512a9bf ("mptcp: use plain
  bool instead of custom binary enum") and more that are not in this
  version, because they modify the context and the size of __unused. The
  conflict is easy to resolve, by not modifying data_avail type. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/protocol.c | 6 ++++++
 net/mptcp/protocol.h | 3 ++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e4d446f32761..ba6248372aee 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2471,6 +2471,12 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 		     struct mptcp_subflow_context *subflow)
 {
+	/* The first subflow can already be closed and still in the list */
+	if (subflow->close_event_done)
+		return;
+
+	subflow->close_event_done = true;
+
 	if (sk->sk_state == TCP_ESTABLISHED)
 		mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index ecbea95970f6..b9a4f6364b78 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -500,7 +500,8 @@ struct mptcp_subflow_context {
 		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
 		valid_csum_seen : 1,        /* at least one csum validated */
 		is_mptfo : 1,	    /* subflow is doing TFO */
-		__unused : 10;
+		close_event_done : 1,       /* has done the post-closed part */
+		__unused : 9;
 	enum mptcp_data_avail data_avail;
 	bool	scheduled;
 	u32	remote_nonce;
-- 
2.45.2

Re: [PATCH 6.6.y] mptcp: avoid duplicated SUB_CLOSED events

[Greg KH]

On Tue, Sep 03, 2024 at 12:17:48PM +0200, Matthieu Baerts (NGI0) wrote:
> commit d82809b6c5f2676b382f77a5cbeb1a5d91ed2235 upstream.
> 
> The initial subflow might have already been closed, but still in the
> connection list. When the worker is instructed to close the subflows
> that have been marked as closed, it might then try to close the initial
> subflow again.
> 
>  A consequence of that is that the SUB_CLOSED event can be seen twice:
> 
>   # ip mptcp endpoint
>   1.1.1.1 id 1 subflow dev eth0
>   2.2.2.2 id 2 subflow dev eth1
> 
>   # ip mptcp monitor &
>   [         CREATED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
>   [     ESTABLISHED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
>   [  SF_ESTABLISHED] remid=0 locid=2 saddr4=2.2.2.2 daddr4=9.9.9.9
> 
>   # ip mptcp endpoint delete id 1
>   [       SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
>   [       SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9
> 
> The first one is coming from mptcp_pm_nl_rm_subflow_received(), and the
> second one from __mptcp_close_subflow().
> 
> To avoid doing the post-closed processing twice, the subflow is now
> marked as closed the first time.
> 
> Note that it is not enough to check if we are dealing with the first
> subflow and check its sk_state: the subflow might have been reset or
> closed before calling mptcp_close_ssk().
> 
> Fixes: b911c97c7dc7 ("mptcp: add netlink event support")
> Cc: stable@vger.kernel.org
> Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
> Reviewed-by: Mat Martineau <martineau@kernel.org>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
> [ Conflict in protocol.h due to commit f1f26512a9bf ("mptcp: use plain
>   bool instead of custom binary enum") and more that are not in this
>   version, because they modify the context and the size of __unused. The
>   conflict is easy to resolve, by not modifying data_avail type. ]
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> ---
>  net/mptcp/protocol.c | 6 ++++++
>  net/mptcp/protocol.h | 3 ++-
>  2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
> index e4d446f32761..ba6248372aee 100644
> --- a/net/mptcp/protocol.c
> +++ b/net/mptcp/protocol.c
> @@ -2471,6 +2471,12 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
>  void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
>  		     struct mptcp_subflow_context *subflow)
>  {
> +	/* The first subflow can already be closed and still in the list */
> +	if (subflow->close_event_done)
> +		return;
> +
> +	subflow->close_event_done = true;
> +
>  	if (sk->sk_state == TCP_ESTABLISHED)
>  		mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL);
>  
> diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
> index ecbea95970f6..b9a4f6364b78 100644
> --- a/net/mptcp/protocol.h
> +++ b/net/mptcp/protocol.h
> @@ -500,7 +500,8 @@ struct mptcp_subflow_context {
>  		stale : 1,	    /* unable to snd/rcv data, do not use for xmit */
>  		valid_csum_seen : 1,        /* at least one csum validated */
>  		is_mptfo : 1,	    /* subflow is doing TFO */
> -		__unused : 10;
> +		close_event_done : 1,       /* has done the post-closed part */
> +		__unused : 9;
>  	enum mptcp_data_avail data_avail;
>  	bool	scheduled;
>  	u32	remote_nonce;
> -- 
> 2.45.2
> 
> 

Now applied.