From: Dima Zavin Date: Tue, 4 Oct 2011 23:58:03 +0000 (-0700) Subject: input: evdev: only allow reading events if a full packet is present X-Git-Tag: firefly_0821_release~7613^2~280 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=487319375187798f489ade0c4df1f14dc43aff63;p=firefly-linux-kernel-4.4.55.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 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 --- diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index 07b6c8153913..13a741ae6045 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;