This is a note to let you know that I've just added the patch titled can: flexcan: fix failure handling of pm_runtime_get_sync() to the 5.4-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: can-flexcan-fix-failure-handling-of-pm_runtime_get_s.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit e998799ed7f52213cd2e5960e3e0a0f86abd42aa Author: Zhang Qilong <zhangqilong3@xxxxxxxxxx> Date: Sun Nov 8 16:30:00 2020 +0800 can: flexcan: fix failure handling of pm_runtime_get_sync() [ Upstream commit b7ee5bc3e1006433601a058a6a7c24c5272635f4 ] pm_runtime_get_sync() will increment pm usage at first and it will resume the device later. If runtime of the device has error or device is in inaccessible state(or other error state), resume operation will fail. If we do not call put operation to decrease the reference, it will result in reference leak in the two functions flexcan_get_berr_counter() and flexcan_open(). Moreover, this device cannot enter the idle state and always stay busy or other non-idle state later. So we should fix it through adding pm_runtime_put_noidle(). Fixes: ca10989632d88 ("can: flexcan: implement can Runtime PM") Signed-off-by: Zhang Qilong <zhangqilong3@xxxxxxxxxx> Link: https://lore.kernel.org/r/20201108083000.2599705-1-zhangqilong3@xxxxxxxxxx Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 130f3022d3396..b22cd8d14716a 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -614,8 +614,10 @@ static int flexcan_get_berr_counter(const struct net_device *dev, int err; err = pm_runtime_get_sync(priv->dev); - if (err < 0) + if (err < 0) { + pm_runtime_put_noidle(priv->dev); return err; + } err = __flexcan_get_berr_counter(dev, bec); @@ -1282,8 +1284,10 @@ static int flexcan_open(struct net_device *dev) int err; err = pm_runtime_get_sync(priv->dev); - if (err < 0) + if (err < 0) { + pm_runtime_put_noidle(priv->dev); return err; + } err = open_candev(dev); if (err)