From: David Herrmann Date: Tue, 1 Nov 2011 16:27:50 +0000 (+0100) Subject: Bluetooth: hidp: Fix module reference cleanup X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=25df0845e054f70a8735ee0184739472d8a573c9;p=linux-beck.git Bluetooth: hidp: Fix module reference cleanup Calling module_put(THIS_MODULE) is *never* safe when we cannot go sure that we own at least two references. This is because the call may unload our module before it returns and then the "return" will jump into invalid memory. Gladly, module.h provides a wrapper for kthread-users: module_put_and_exit(). This puts our module and then exits the kthread without returning to the module. This patch fixes the hidp kthread to use this wrapper instead of manually freeing its own reference. See nfsd or lockd for other kthreads using this. Calling __module_get() inside the kthread is safe as the hidp module will always wait until the kthread sets "waiting_for_startup" to 0. Signed-off-by: David Herrmann Signed-off-by: Gustavo F. Padovan --- diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c index 2efd6cc58b66..56dc660d234a 100644 --- a/net/bluetooth/hidp/core.c +++ b/net/bluetooth/hidp/core.c @@ -94,7 +94,6 @@ static struct hidp_session *__hidp_get_session(bdaddr_t *bdaddr) static void __hidp_link_session(struct hidp_session *session) { - __module_get(THIS_MODULE); list_add(&session->list, &hidp_session_list); } @@ -103,7 +102,6 @@ static void __hidp_unlink_session(struct hidp_session *session) hci_conn_put_device(session->conn); list_del(&session->list); - module_put(THIS_MODULE); } static void __hidp_copy_session(struct hidp_session *session, struct hidp_conninfo *ci) @@ -703,6 +701,7 @@ static int hidp_session(void *arg) BT_DBG("session %p", session); + __module_get(THIS_MODULE); set_user_nice(current, -15); init_waitqueue_entry(&ctrl_wait, current); @@ -781,6 +780,7 @@ static int hidp_session(void *arg) kfree(session->rd_data); kfree(session); + module_put_and_exit(0); return 0; }