[PATCH 1/3] input: evdev: only allow reading events if a full packet is present
From: Dima Zavin
Date: Fri Dec 16 2011 - 13:07:13 EST
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.
Cc: Jeff Brown <jeffbrown@xxxxxxxxxxx>
Signed-off-by: Dima Zavin <dima@xxxxxxxxxxx>
---
drivers/input/evdev.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 4cf2534..03344b3 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;
--
1.7.3.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/