This is a note to let you know that I've just added the patch titled
mctp i2c: don't count unused / invalid keys for flow release
to the 6.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mctp-i2c-don-t-count-unused-invalid-keys-for-flow-re.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 692c01925ad7fffd7c22ea0ea7d3ad0fc87ff1d0
Author: Jeremy Kerr <jk@xxxxxxxxxxxxxxxxxxxx>
Date: Thu Nov 10 13:31:35 2022 +0800
mctp i2c: don't count unused / invalid keys for flow release
[ Upstream commit 9cbd48d5fa14e4c65f8580de16686077f7cea02b ]
We're currently hitting the WARN_ON in mctp_i2c_flow_release:
if (midev->release_count > midev->i2c_lock_count) {
WARN_ONCE(1, "release count overflow");
This may be hit if we expire a flow before sending the first packet it
contains - as we will not be pairing the increment of release_count
(performed on flow release) with the i2c lock operation (only
performed on actual TX).
To fix this, only release a flow if we've encountered it previously (ie,
dev_flow_state does not indicate NEW), as we will mark the flow as
ACTIVE at the same time as accounting for the i2c lock operation. We
also need to add an INVALID flow state, to indicate when we've done the
release.
Fixes: f5b8abf9fc3d ("mctp i2c: MCTP I2C binding driver")
Reported-by: Jian Zhang <zhangjian.3032@xxxxxxxxxxxxx>
Tested-by: Jian Zhang <zhangjian.3032@xxxxxxxxxxxxx>
Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221110053135.329071-1-jk@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/mctp/mctp-i2c.c b/drivers/net/mctp/mctp-i2c.c
index 53846c6b56ca..aca3697b0962 100644
--- a/drivers/net/mctp/mctp-i2c.c
+++ b/drivers/net/mctp/mctp-i2c.c
@@ -43,6 +43,7 @@
enum {
MCTP_I2C_FLOW_STATE_NEW = 0,
MCTP_I2C_FLOW_STATE_ACTIVE,
+ MCTP_I2C_FLOW_STATE_INVALID,
};
/* List of all struct mctp_i2c_client
@@ -374,12 +375,18 @@ mctp_i2c_get_tx_flow_state(struct mctp_i2c_dev *midev, struct sk_buff *skb)
*/
if (!key->valid) {
state = MCTP_I2C_TX_FLOW_INVALID;
-
- } else if (key->dev_flow_state == MCTP_I2C_FLOW_STATE_NEW) {
- key->dev_flow_state = MCTP_I2C_FLOW_STATE_ACTIVE;
- state = MCTP_I2C_TX_FLOW_NEW;
} else {
- state = MCTP_I2C_TX_FLOW_EXISTING;
+ switch (key->dev_flow_state) {
+ case MCTP_I2C_FLOW_STATE_NEW:
+ key->dev_flow_state = MCTP_I2C_FLOW_STATE_ACTIVE;
+ state = MCTP_I2C_TX_FLOW_NEW;
+ break;
+ case MCTP_I2C_FLOW_STATE_ACTIVE:
+ state = MCTP_I2C_TX_FLOW_EXISTING;
+ break;
+ default:
+ state = MCTP_I2C_TX_FLOW_INVALID;
+ }
}
spin_unlock_irqrestore(&key->lock, flags);
@@ -617,21 +624,31 @@ static void mctp_i2c_release_flow(struct mctp_dev *mdev,
{
struct mctp_i2c_dev *midev = netdev_priv(mdev->dev);
+ bool queue_release = false;
unsigned long flags;
spin_lock_irqsave(&midev->lock, flags);
- midev->release_count++;
- spin_unlock_irqrestore(&midev->lock, flags);
-
- /* Ensure we have a release operation queued, through the fake
- * marker skb
+ /* if we have seen the flow/key previously, we need to pair the
+ * original lock with a release
*/
- spin_lock(&midev->tx_queue.lock);
- if (!midev->unlock_marker.next)
- __skb_queue_tail(&midev->tx_queue, &midev->unlock_marker);
- spin_unlock(&midev->tx_queue.lock);
+ if (key->dev_flow_state == MCTP_I2C_FLOW_STATE_ACTIVE) {
+ midev->release_count++;
+ queue_release = true;
+ }
+ key->dev_flow_state = MCTP_I2C_FLOW_STATE_INVALID;
+ spin_unlock_irqrestore(&midev->lock, flags);
- wake_up(&midev->tx_wq);
+ if (queue_release) {
+ /* Ensure we have a release operation queued, through the fake
+ * marker skb
+ */
+ spin_lock(&midev->tx_queue.lock);
+ if (!midev->unlock_marker.next)
+ __skb_queue_tail(&midev->tx_queue,
+ &midev->unlock_marker);
+ spin_unlock(&midev->tx_queue.lock);
+ wake_up(&midev->tx_wq);
+ }
}
static const struct net_device_ops mctp_i2c_ops = {
