[PATCH net-next] rxrpc: use timer_shutdown_sync() for cleanup operations
From: Yu Liao <hidden>
Date: 2023-08-21 01:14:21
Subsystem:
networking [general], rxrpc sockets (af_rxrpc), the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Howells, Marc Dionne, Linus Torvalds
There was a race [1] between timer and rxrpc_exit_net() which was solved by calling del_timer_sync() before and after cancel_work_sync(). A better solution is to use timer_shutdown_sync() [2] to solve the circular dependency problem. The correct ordering of calls in this case is: timer_shutdown_sync(&mything->timer); workqueue_destroy(&mything->workqueue); After calling timer_shutdown_sync(), timer won't be rearmed from the workqueue. [1] https://lore.kernel.org/164984498582.2000115.4023190177137486137.stgit@warthog.procyon.org.uk (local) [2] https://lore.kernel.org/r/20221123201625.314230270@linutronix.de (local) Signed-off-by: Yu Liao <redacted> --- net/rxrpc/conn_object.c | 5 ++--- net/rxrpc/net_ns.c | 4 +--- 2 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index ac85d4644a3c..1afd677848af 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c@@ -317,9 +317,8 @@ static void rxrpc_clean_up_connection(struct work_struct *work) !conn->channels[3].call); ASSERT(list_empty(&conn->cache_link)); - del_timer_sync(&conn->timer); - cancel_work_sync(&conn->processor); /* Processing may restart the timer */ - del_timer_sync(&conn->timer); + timer_shutdown_sync(&conn->timer); + cancel_work_sync(&conn->processor); write_lock(&rxnet->conn_lock); list_del_init(&conn->proc_link);
diff --git a/net/rxrpc/net_ns.c b/net/rxrpc/net_ns.c
index a0319c040c25..38cfbd2c7991 100644
--- a/net/rxrpc/net_ns.c
+++ b/net/rxrpc/net_ns.c@@ -101,10 +101,8 @@ static __net_exit void rxrpc_exit_net(struct net *net) struct rxrpc_net *rxnet = rxrpc_net(net); rxnet->live = false; - del_timer_sync(&rxnet->peer_keepalive_timer); + timer_shutdown_sync(&rxnet->peer_keepalive_timer); cancel_work_sync(&rxnet->peer_keepalive_work); - /* Remove the timer again as the worker may have restarted it. */ - del_timer_sync(&rxnet->peer_keepalive_timer); rxrpc_destroy_all_calls(rxnet); rxrpc_destroy_all_connections(rxnet); rxrpc_destroy_all_peers(rxnet);
--
2.25.1