From f1c6a420b1d3167325496e16474a56a934e4ccda Mon Sep 17 00:00:00 2001
From: Gleb Smirnoff <glebius@FreeBSD.org>
Date: Sat, 19 Feb 2005 14:41:49 +0000
Subject: [PATCH] Reimplement recursion protection, checking whether current
 thread holds sockbuf mutex.

Reviewed by:	rwatson
---
 sys/netgraph/ng_ksocket.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sys/netgraph/ng_ksocket.c b/sys/netgraph/ng_ksocket.c
index d311beb41fff..3d2179821326 100644
--- a/sys/netgraph/ng_ksocket.c
+++ b/sys/netgraph/ng_ksocket.c
@@ -897,6 +897,12 @@ ng_ksocket_rcvdata(hook_p hook, item_p item)
 	struct mbuf *m;
 	struct sa_tag *stag;
 
+	/* Avoid reentrantly sending on the socket */
+	if (SOCKBUF_OWNED(&so->so_snd)) {
+		NG_FREE_ITEM(item);
+		return (EDEADLK);
+	}
+
 	/* Extract data */
 	NGI_GET_M(item, m);
 	NG_FREE_ITEM(item);