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FAILED: patch "[PATCH] mptcp: process pending subflow error on close" failed to apply to 5.15-stable tree

PATCH Applied [email protected] 2 participants 3 messages Oct 4, 2023 – Mar 4, 2024

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#0 lore raw

The patch below does not apply to the 5.15-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 <[email protected]>.

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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 9f1a98813b4b686482e5ef3c9d998581cace0ba6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023100447-durable-snowiness-8b36@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 9f1a98813b4b686482e5ef3c9d998581cace0ba6 Mon Sep 17 00:00:00 2001
From: Paolo Abeni <[email protected]>
Date: Sat, 16 Sep 2023 12:52:47 +0200
Subject: [PATCH] mptcp: process pending subflow error on close

On incoming TCP reset, subflow closing could happen before error propagation. That in turn could cause the socket error being ignored, and a missing socket state transition, as reported by Daire-Byrne.

Address the issues explicitly checking for subflow socket error at close time. To avoid code duplication, factor-out of __mptcp_error_report() a new helper implementing the relevant bits.

net/mptcp/protocol.c +34 -29
index 915860027b1a..1c96b8da71df 100644
@@ -770,40 +770,44 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
 	return moved;
 }
 
+static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
+{
+	int err = sock_error(ssk);
+	int ssk_state;
+
+	if (!err)
+		return false;
+
+	/* only propagate errors on fallen-back sockets or
+	 * on MPC connect
+	 */
+	if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
+		return false;
+
+	/* We need to propagate only transition to CLOSE state.
+	 * Orphaned socket will see such state change via
+	 * subflow_sched_work_if_closed() and that path will properly
+	 * destroy the msk as needed.
+	 */
+	ssk_state = inet_sk_state_load(ssk);
+	if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
+		inet_sk_state_store(sk, ssk_state);
+	WRITE_ONCE(sk->sk_err, -err);
+
+	/* This barrier is coupled with smp_rmb() in mptcp_poll() */
+	smp_wmb();
+	sk_error_report(sk);
+	return true;
+}
+
 void __mptcp_error_report(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow;
 	struct mptcp_sock *msk = mptcp_sk(sk);
 
-	mptcp_for_each_subflow(msk, subflow) {
-		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-		int err = sock_error(ssk);
-		int ssk_state;
-
-		if (!err)
-			continue;
-
-		/* only propagate errors on fallen-back sockets or
-		 * on MPC connect
-		 */
-		if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
-			continue;
-
-		/* We need to propagate only transition to CLOSE state.
-		 * Orphaned socket will see such state change via
-		 * subflow_sched_work_if_closed() and that path will properly
-		 * destroy the msk as needed.
-		 */
-		ssk_state = inet_sk_state_load(ssk);
-		if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
-			inet_sk_state_store(sk, ssk_state);
-		WRITE_ONCE(sk->sk_err, -err);
-
-		/* This barrier is coupled with smp_rmb() in mptcp_poll() */
-		smp_wmb();
-		sk_error_report(sk);
-		break;
-	}
+	mptcp_for_each_subflow(msk, subflow)
+		if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
+			break;
 }
 
 /* In most cases we will be able to lock the mptcp socket.  If its already
@@ -2428,6 +2432,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 	}
 
 out_release:
+	__mptcp_subflow_error_report(sk, ssk);
 	release_sock(ssk);
 
 	sock_put(ssk);
#1 lore raw

PATCH 1/1 mptcp: process pending subflow error on close

From: Paolo Abeni <[email protected]>

On incoming TCP reset, subflow closing could happen before error propagation. That in turn could cause the socket error being ignored, and a missing socket state transition, as reported by Daire-Byrne.

Address the issues explicitly checking for subflow socket error at close time. To avoid code duplication, factor-out of __mptcp_error_report() a new helper implementing the relevant bits.

Fixes 15cc10453398 ("mptcp: deliver ssk errors to msk")
(cherry picked from commit 9f1a98813b4b686482e5ef3c9d998581cace0ba6)

---
Notes:
- a conflict in protocol.c, because commit 34cec5cd7abc ("mptcp: fix accept vs worker race") has not been backported to v5.15. It introduces a new label (out_release) in the modified context.

---
 net/mptcp/protocol.c | 63 ++++++++++++++++++++++++--------------------
 1 file changed, 34 insertions(+), 29 deletions(-)
net/mptcp/protocol.c +34 -29
index 8382345af1d86..47844df9c0b4c 100644
@@ -688,40 +688,44 @@ static bool __mptcp_ofo_queue(struct mptcp_sock *msk)
 	return moved;
 }
 
+static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
+{
+	int err = sock_error(ssk);
+	int ssk_state;
+
+	if (!err)
+		return false;
+
+	/* only propagate errors on fallen-back sockets or
+	 * on MPC connect
+	 */
+	if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
+		return false;
+
+	/* We need to propagate only transition to CLOSE state.
+	 * Orphaned socket will see such state change via
+	 * subflow_sched_work_if_closed() and that path will properly
+	 * destroy the msk as needed.
+	 */
+	ssk_state = inet_sk_state_load(ssk);
+	if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
+		inet_sk_state_store(sk, ssk_state);
+	WRITE_ONCE(sk->sk_err, -err);
+
+	/* This barrier is coupled with smp_rmb() in mptcp_poll() */
+	smp_wmb();
+	sk_error_report(sk);
+	return true;
+}
+
 void __mptcp_error_report(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow;
 	struct mptcp_sock *msk = mptcp_sk(sk);
 
-	mptcp_for_each_subflow(msk, subflow) {
-		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-		int err = sock_error(ssk);
-		int ssk_state;
-
-		if (!err)
-			continue;
-
-		/* only propagate errors on fallen-back sockets or
-		 * on MPC connect
-		 */
-		if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
-			continue;
-
-		/* We need to propagate only transition to CLOSE state.
-		 * Orphaned socket will see such state change via
-		 * subflow_sched_work_if_closed() and that path will properly
-		 * destroy the msk as needed.
-		 */
-		ssk_state = inet_sk_state_load(ssk);
-		if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
-			inet_sk_state_store(sk, ssk_state);
-		WRITE_ONCE(sk->sk_err, -err);
-
-		/* This barrier is coupled with smp_rmb() in mptcp_poll() */
-		smp_wmb();
-		sk_error_report(sk);
-		break;
-	}
+	mptcp_for_each_subflow(msk, subflow)
+		if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
+			break;
 }
 
 /* In most cases we will be able to lock the mptcp socket.  If its already
@@ -2309,6 +2313,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 		/* close acquired an extra ref */
 		__sock_put(ssk);
 	}
+	__mptcp_subflow_error_report(sk, ssk);
 	release_sock(ssk);
 
 	sock_put(ssk);
Signature · 1 line
2.43.0
author maintainer Applied
#2 lore raw

Patch "mptcp: process pending subflow error on close" has been added to the 5.15-stable tree

This is a note to let you know that I've just added the patch titled

mptcp: process pending subflow error on close

to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mptcp-process-pending-subflow-error-on-close.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From [email protected] Wed Feb 28 18:33:29 2024
From: "Matthieu Baerts (NGI0)" <[email protected]>
Date: Wed, 28 Feb 2024 18:33:18 +0100
Subject: mptcp: process pending subflow error on close
To: [email protected], [email protected]
Cc: MPTCP Upstream <[email protected]>, Paolo Abeni <[email protected]>, Mat Martineau <[email protected]>, Matthieu Baerts <[email protected]>, "David S . Miller" <[email protected]>, Matthieu Baerts <[email protected]>
Message-ID: <[email protected]>

From: Paolo Abeni <[email protected]>

commit 9f1a98813b4b686482e5ef3c9d998581cace0ba6 upstream.

On incoming TCP reset, subflow closing could happen before error propagation. That in turn could cause the socket error being ignored, and a missing socket state transition, as reported by Daire-Byrne.

Address the issues explicitly checking for subflow socket error at close time. To avoid code duplication, factor-out of __mptcp_error_report() a new helper implementing the relevant bits.

---
 net/mptcp/protocol.c |   63 +++++++++++++++++++++++++++------------------------
 1 file changed, 34 insertions(+), 29 deletions(-)
net/mptcp/protocol.c +34 -29
@@ -688,40 +688,44 @@ static bool __mptcp_ofo_queue(struct mpt
 	return moved;
 }
 
-void __mptcp_error_report(struct sock *sk)
+static bool __mptcp_subflow_error_report(struct sock *sk, struct sock *ssk)
 {
-	struct mptcp_subflow_context *subflow;
-	struct mptcp_sock *msk = mptcp_sk(sk);
+	int err = sock_error(ssk);
+	int ssk_state;
 
-	mptcp_for_each_subflow(msk, subflow) {
-		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
-		int err = sock_error(ssk);
-		int ssk_state;
+	if (!err)
+		return false;
 
-		if (!err)
-			continue;
+	/* only propagate errors on fallen-back sockets or
+	 * on MPC connect
+	 */
+	if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(mptcp_sk(sk)))
+		return false;
 
-		/* only propagate errors on fallen-back sockets or
-		 * on MPC connect
-		 */
-		if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
-			continue;
+	/* We need to propagate only transition to CLOSE state.
+	 * Orphaned socket will see such state change via
+	 * subflow_sched_work_if_closed() and that path will properly
+	 * destroy the msk as needed.
+	 */
+	ssk_state = inet_sk_state_load(ssk);
+	if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
+		inet_sk_state_store(sk, ssk_state);
+	WRITE_ONCE(sk->sk_err, -err);
+
+	/* This barrier is coupled with smp_rmb() in mptcp_poll() */
+	smp_wmb();
+	sk_error_report(sk);
+	return true;
+}
 
-		/* We need to propagate only transition to CLOSE state.
-		 * Orphaned socket will see such state change via
-		 * subflow_sched_work_if_closed() and that path will properly
-		 * destroy the msk as needed.
-		 */
-		ssk_state = inet_sk_state_load(ssk);
-		if (ssk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DEAD))
-			inet_sk_state_store(sk, ssk_state);
-		WRITE_ONCE(sk->sk_err, -err);
-
-		/* This barrier is coupled with smp_rmb() in mptcp_poll() */
-		smp_wmb();
-		sk_error_report(sk);
-		break;
-	}
+void __mptcp_error_report(struct sock *sk)
+{
+	struct mptcp_subflow_context *subflow;
+	struct mptcp_sock *msk = mptcp_sk(sk);
+
+	mptcp_for_each_subflow(msk, subflow)
+		if (__mptcp_subflow_error_report(sk, mptcp_subflow_tcp_sock(subflow)))
+			break;
 }
 
 /* In most cases we will be able to lock the mptcp socket.  If its already
@@ -2309,6 +2313,7 @@ static void __mptcp_close_ssk(struct soc
 		/* close acquired an extra ref */
 		__sock_put(ssk);
 	}
+	__mptcp_subflow_error_report(sk, ssk);
 	release_sock(ssk);
 
 	sock_put(ssk);

Patches currently in stable-queue which might be from [email protected] are

queue-5.15/selftests-mptcp-add-missing-kconfig-for-nf-filter.patch queue-5.15/selftests-mptcp-add-missing-kconfig-for-nf-filter-in-v6.patch queue-5.15/mptcp-add-needs_id-for-netlink-appending-addr.patch queue-5.15/mptcp-rename-timer-related-helper-to-less-confusing-names.patch queue-5.15/mptcp-process-pending-subflow-error-on-close.patch queue-5.15/mptcp-clean-up-harmless-false-expressions.patch queue-5.15/mptcp-move-__mptcp_error_report-in-protocol.c.patch