Commit 566cf5b6 authored by Dima Zavin's avatar Dima Zavin Committed by Dmitry Torokhov

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: default avatarDima Zavin <dima@android.com>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 36a281e2
...@@ -369,7 +369,7 @@ static int evdev_fetch_next_event(struct evdev_client *client, ...@@ -369,7 +369,7 @@ static int evdev_fetch_next_event(struct evdev_client *client,
spin_lock_irq(&client->buffer_lock); spin_lock_irq(&client->buffer_lock);
have_event = client->head != client->tail; have_event = client->packet_head != client->tail;
if (have_event) { if (have_event) {
*event = client->buffer[client->tail++]; *event = client->buffer[client->tail++];
client->tail &= client->bufsize - 1; client->tail &= client->bufsize - 1;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment