From e7a41b276974d35bac948f08327d8f4297d739ba Mon Sep 17 00:00:00 2001 From: David Windsor Date: Tue, 2 Apr 2019 08:37:10 -0400 Subject: [PATCH] dlm: check if workqueues are NULL before flushing/destroying [ Upstream commit b355516f450703c9015316e429b66a93dfff0e6f ] If the DLM lowcomms stack is shut down before any DLM traffic can be generated, flush_workqueue() and destroy_workqueue() can be called on empty send and/or recv workqueues. Insert guard conditionals to only call flush_workqueue() and destroy_workqueue() on workqueues that are not NULL. Signed-off-by: David Windsor Signed-off-by: David Teigland Signed-off-by: Sasha Levin --- fs/dlm/lowcomms.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c index a5e4a22..a93ebff 100644 --- a/fs/dlm/lowcomms.c +++ b/fs/dlm/lowcomms.c @@ -1630,8 +1630,10 @@ static void clean_writequeues(void) static void work_stop(void) { - destroy_workqueue(recv_workqueue); - destroy_workqueue(send_workqueue); + if (recv_workqueue) + destroy_workqueue(recv_workqueue); + if (send_workqueue) + destroy_workqueue(send_workqueue); } static int work_start(void) @@ -1691,13 +1693,17 @@ static void work_flush(void) struct hlist_node *n; struct connection *con; - flush_workqueue(recv_workqueue); - flush_workqueue(send_workqueue); + if (recv_workqueue) + flush_workqueue(recv_workqueue); + if (send_workqueue) + flush_workqueue(send_workqueue); do { ok = 1; foreach_conn(stop_conn); - flush_workqueue(recv_workqueue); - flush_workqueue(send_workqueue); + if (recv_workqueue) + flush_workqueue(recv_workqueue); + if (send_workqueue) + flush_workqueue(send_workqueue); for (i = 0; i < CONN_HASH_SIZE && ok; i++) { hlist_for_each_entry_safe(con, n, &connection_hash[i], list) { -- 2.7.4