From cd25733eed9efe88fb3dfb9c371d1a412492284a Mon Sep 17 00:00:00 2001 From: Dima Zavin Date: Tue, 4 Oct 2011 16:58:03 -0700 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 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. Change-Id: If01ab371bc7de1bf1f90c122dcc5a29242b01a09 Signed-off-by: Dima Zavin --- 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 07b6c81..13a741a 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -381,7 +381,7 @@ 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; -- 2.7.4