From 566cf5b6e34504aaccb76167ecccd7e7e69e6456 Mon Sep 17 00:00:00 2001 From: Dima Zavin Date: Fri, 30 Dec 2011 15:16:44 -0800 Subject: [PATCH] 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 --- drivers/input/evdev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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; -- 2.20.1