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FAILED: patch "[PATCH] sctp: hold endpoint before calling cb in" failed to apply to 4.19-stable tree

PATCH [email protected] 1 participant 1 message Jan 7, 2022

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The patch below does not apply to the 4.19-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]>.

thanks,

greg k-h

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

From f9d31c4cf4c11ff10317f038b9c6f7c3bda6cdd4 Mon Sep 17 00:00:00 2001
From: Xin Long <[email protected]>
Date: Fri, 31 Dec 2021 18:37:37 -0500
Subject: [PATCH] sctp: hold endpoint before calling cb in
sctp_transport_lookup_process

The same fix in commit 5ec7d18d1813 ("sctp: use call_rcu to free endpoint") is also needed for dumping one asoc and sock after the lookup.

Fixes 86fdb3448cc1 ("sctp: ensure ep is not destroyed before doing the dump")
Signed-off-by Xin Long <[email protected]>
Signed-off-by David S. Miller <[email protected]>
include/net/sctp/sctp.h +1 -2
index d314a180ab93..3ae61ce2eabd 100644
@@ -112,8 +112,7 @@ struct sctp_transport *sctp_transport_get_next(struct net *net,
 			struct rhashtable_iter *iter);
 struct sctp_transport *sctp_transport_get_idx(struct net *net,
 			struct rhashtable_iter *iter, int pos);
-int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
-				  struct net *net,
+int sctp_transport_lookup_process(sctp_callback_t cb, struct net *net,
 				  const union sctp_addr *laddr,
 				  const union sctp_addr *paddr, void *p);
 int sctp_transport_traverse_process(sctp_callback_t cb, sctp_callback_t cb_done,
net/sctp/diag.c +21 -25

91 lines not on this page · raw message

net/sctp/socket.c +15 -7
index ad5028a07b18..da08671a3f80 100644
@@ -5317,23 +5317,31 @@ int sctp_for_each_endpoint(int (*cb)(struct sctp_endpoint *, void *),
 }
 EXPORT_SYMBOL_GPL(sctp_for_each_endpoint);
 
-int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
-				  struct net *net,
+int sctp_transport_lookup_process(sctp_callback_t cb, struct net *net,
 				  const union sctp_addr *laddr,
 				  const union sctp_addr *paddr, void *p)
 {
 	struct sctp_transport *transport;
-	int err;
+	struct sctp_endpoint *ep;
+	int err = -ENOENT;
 
 	rcu_read_lock();
 	transport = sctp_addrs_lookup_transport(net, laddr, paddr);
+	if (!transport) {
+		rcu_read_unlock();
+		return err;
+	}
+	ep = transport->asoc->ep;
+	if (!sctp_endpoint_hold(ep)) { /* asoc can be peeled off */
+		sctp_transport_put(transport);
+		rcu_read_unlock();
+		return err;
+	}
 	rcu_read_unlock();
-	if (!transport)
-		return -ENOENT;
 
-	err = cb(transport, p);
+	err = cb(ep, transport, p);
+	sctp_endpoint_put(ep);
 	sctp_transport_put(transport);
-
 	return err;
 }
 EXPORT_SYMBOL_GPL(sctp_transport_lookup_process);