Input: reduce raciness when input handlers disconnect

There is a race between input handler's release() and disconnect()
methods: when input handler disconnects it wakes up all regular
users and then process to walk user list to wake up async. users.
While disconnect() walks the list release() removes elements of
the same list causing oopses.

While this is not a substibute for proper locking we can reduce
odds of getting an oops if we wake up normal readers after walking
the list.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index a4c3729..93b407c 100644 (file)
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -700,9 +700,9 @@ static void evdev_disconnect(struct input_handle *handle)
        if (evdev->open) {
                input_flush_device(handle, NULL);
                input_close_device(handle);
-               wake_up_interruptible(&evdev->wait);
                list_for_each_entry(client, &evdev->client_list, node)
                        kill_fasync(&client->fasync, SIGIO, POLL_HUP);
+               wake_up_interruptible(&evdev->wait);
        } else
                evdev_free(evdev);
 }

diff --git a/drivers/input/joydev.c b/drivers/input/joydev.c
index 9bcc542..c83bfe8 100644 (file)
--- a/drivers/input/joydev.c
+++ b/drivers/input/joydev.c
@@ -595,9 +595,9 @@ static void joydev_disconnect(struct input_handle *handle)
 
        if (joydev->open) {
                input_close_device(handle);
-               wake_up_interruptible(&joydev->wait);
                list_for_each_entry(client, &joydev->client_list, node)
                        kill_fasync(&client->fasync, SIGIO, POLL_HUP);
+               wake_up_interruptible(&joydev->wait);
        } else
                joydev_free(joydev);
 }

diff --git a/drivers/input/mousedev.c b/drivers/input/mousedev.c
index 7678e98..dc78f62 100644 (file)
--- a/drivers/input/mousedev.c
+++ b/drivers/input/mousedev.c
@@ -767,9 +767,9 @@ static void mousedev_disconnect(struct input_handle *handle)
 
        if (mousedev->open) {
                input_close_device(handle);
-               wake_up_interruptible(&mousedev->wait);
                list_for_each_entry(client, &mousedev->client_list, node)
                        kill_fasync(&client->fasync, SIGIO, POLL_HUP);
+               wake_up_interruptible(&mousedev->wait);
        } else
                mousedev_free(mousedev);
 }

diff --git a/drivers/input/tsdev.c b/drivers/input/tsdev.c
index 5e5b5c9..af4581d 100644 (file)
--- a/drivers/input/tsdev.c
+++ b/drivers/input/tsdev.c
@@ -477,9 +477,9 @@ static void tsdev_disconnect(struct input_handle *handle)
 
        if (tsdev->open) {
                input_close_device(handle);
-               wake_up_interruptible(&tsdev->wait);
                list_for_each_entry(client, &tsdev->client_list, node)
                        kill_fasync(&client->fasync, SIGIO, POLL_HUP);
+               wake_up_interruptible(&tsdev->wait);
        } else
                tsdev_free(tsdev);
 }