From: Dima Zavin Date: Fri, 30 Dec 2011 23:16:44 +0000 (-0800) Subject: Input: evdev - only allow reading events if a full packet is present X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=566cf5b6e34504aaccb76167ecccd7e7e69e6456;p=deliverable%2Flinux.git Input: evdev - only allow reading events if a full packet is present Without this, it was possible for the reader to get ahead of packet_head. If the input device generated a partial packet *right* after the reader got ahead, then we can get into a situation where the device is marked readable, but read always returns 0 until the next packet is finished (i.e a SYN is generated by the input driver). This situation can also happen if we overflow the buffer while a reader is trying to read an event out. Signed-off-by: Dima Zavin Signed-off-by: Dmitry Torokhov --- diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index 4cf25347b015..03344b3c7c15 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -369,7 +369,7 @@ static int evdev_fetch_next_event(struct evdev_client *client, spin_lock_irq(&client->buffer_lock); - have_event = client->head != client->tail; + have_event = client->packet_head != client->tail; if (have_event) { *event = client->buffer[client->tail++]; client->tail &= client->bufsize - 1;