Add a check to xprt_unregister() to catch the case where another

thread has already unregistered the structure. Also add a KASSERT()
to xprt_unregister_locked() to check that the structure hasn't already
been unregistered.

Reviewed by:	jhb
Tested by:	pho
Approved by:	kib (mentor)

1 files changed, 7 insertions, 0 deletions

diff --git a/sys/rpc/svc.c b/sys/rpc/svc.c
index 5db4c56..8c3bd2c 100644
--- a/sys/rpc/svc.c
+++ b/sys/rpc/svc.c
@@ -293,6 +293,8 @@ xprt_unregister_locked(SVCXPRT *xprt)
 {
 	SVCPOOL *pool = xprt->xp_pool;
 
+	KASSERT(xprt->xp_registered == TRUE,
+	    ("xprt_unregister_locked: not registered"));
 	if (xprt->xp_active) {
 		TAILQ_REMOVE(&pool->sp_active, xprt, xp_alink);
 		xprt->xp_active = FALSE;
@@ -307,6 +309,11 @@ xprt_unregister(SVCXPRT *xprt)
 	SVCPOOL *pool = xprt->xp_pool;
 
 	mtx_lock(&pool->sp_lock);
+	if (xprt->xp_registered == FALSE) {
+		/* Already unregistered by another thread */
+		mtx_unlock(&pool->sp_lock);
+		return;
+	}
 	xprt_unregister_locked(xprt);
 	mtx_unlock(&pool->sp_lock);