pktgen: fix module unload for good

BugLink: http://bugs.launchpad.net/bugs/1013748

[ Upstream commit d4b1133558e0d417342d5d2c49e4c35b428ff20d ]

commit c57b5468406 (pktgen: fix crash at module unload) did a very poor
job with list primitives.

1) list_splice() arguments were in the wrong order

2) list_splice(list, head) has undefined behavior if head is not
initialized.

3) We should use the list_splice_init() variant to clear pktgen_threads
list.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 0865ea025c9..c0e0f7679e7 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -3755,13 +3755,13 @@ static void __exit pg_cleanup(void)
 {
         struct pktgen_thread *t;
         struct list_head *q, *n;
-        struct list_head list;
+        LIST_HEAD(list);
 
         /* Stop all interfaces & threads */
         pktgen_exiting = true;
 
         mutex_lock(&pktgen_thread_lock);
-        list_splice(&list, &pktgen_threads);
+        list_splice_init(&pktgen_threads, &list);
         mutex_unlock(&pktgen_thread_lock);
 
         list_for_each_safe(q, n, &list) {