diff mbox series

[net,3/7] mptcp: Acquire the subflow socket lock before modifying MP_PRIO flags

Message ID 20220705213217.146898-4-mathew.j.martineau@linux.intel.com (mailing list archive)
State Accepted
Commit a657430260e5437df16004c8c317821d946b5ead
Delegated to: Netdev Maintainers
Headers show
Series mptcp: Path manager fixes for 5.19 | expand

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netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/cc_maintainers fail 1 blamed authors not CCed: geliangtang@gmail.com; 1 maintainers not CCed: geliangtang@gmail.com
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 5 this patch: 5
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 49 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Mat Martineau July 5, 2022, 9:32 p.m. UTC 
When setting up a subflow's flags for sending MP_PRIO MPTCP options, the
subflow socket lock was not held while reading and modifying several
struct members that are also read and modified in mptcp_write_options().

Acquire the subflow socket lock earlier and send the MP_PRIO ACK with
that lock already acquired. Add a new variant of the
mptcp_subflow_send_ack() helper to use with the subflow lock held.

Fixes: 067065422fcd ("mptcp: add the outgoing MP_PRIO support")
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm_netlink.c | 5 ++++-
 net/mptcp/protocol.c   | 9 +++++++--
 net/mptcp/protocol.h   | 1 +
 3 files changed, 12 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 5ff93b73f33d..ca86c88f89e0 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -728,11 +728,13 @@  static int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
 	mptcp_for_each_subflow(msk, subflow) {
 		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
 		struct mptcp_addr_info local;
+		bool slow;
 
 		local_address((struct sock_common *)ssk, &local);
 		if (!mptcp_addresses_equal(&local, addr, addr->port))
 			continue;
 
+		slow = lock_sock_fast(ssk);
 		if (subflow->backup != bkup)
 			msk->last_snd = NULL;
 		subflow->backup = bkup;
@@ -740,7 +742,8 @@  static int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
 		subflow->request_bkup = bkup;
 
 		pr_debug("send ack for mp_prio");
-		mptcp_subflow_send_ack(ssk);
+		__mptcp_subflow_send_ack(ssk);
+		unlock_sock_fast(ssk, slow);
 
 		return 0;
 	}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e475212f2618..cc21fafd9726 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -506,13 +506,18 @@  static inline bool tcp_can_send_ack(const struct sock *ssk)
 	       (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN));
 }
 
+void __mptcp_subflow_send_ack(struct sock *ssk)
+{
+	if (tcp_can_send_ack(ssk))
+		tcp_send_ack(ssk);
+}
+
 void mptcp_subflow_send_ack(struct sock *ssk)
 {
 	bool slow;
 
 	slow = lock_sock_fast(ssk);
-	if (tcp_can_send_ack(ssk))
-		tcp_send_ack(ssk);
+	__mptcp_subflow_send_ack(ssk);
 	unlock_sock_fast(ssk, slow);
 }
 
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index c14d70c036d0..033c995772dc 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -607,6 +607,7 @@  void __init mptcp_subflow_init(void);
 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how);
 void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 		     struct mptcp_subflow_context *subflow);
+void __mptcp_subflow_send_ack(struct sock *ssk);
 void mptcp_subflow_send_ack(struct sock *ssk);
 void mptcp_subflow_reset(struct sock *ssk);
 void mptcp_subflow_queue_clean(struct sock *ssk);