Commit abe13e9a authored by Shengjiu Wang's avatar Shengjiu Wang Committed by Mathieu Poirier
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rpmsg: char: Add mutex protection for rpmsg_eptdev_open() 



There is no mutex protection for rpmsg_eptdev_open(),
especially for eptdev->ept read and write operation.
It may cause issues when multiple instances call
rpmsg_eptdev_open() in parallel,the return state
may be success or EBUSY.

Fixes: 964e8bed ("rpmsg: char: Return an error if device already open")
Signed-off-by: default avatarShengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1653104105-16779-1-git-send-email-shengjiu.wang@nxp.com


Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
parent b13baccc

drivers/rpmsg/rpmsg_char.c

+6 −1
Original line number Diff line number Diff line
@@ -120,8 +120,11 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) 
	struct rpmsg_device *rpdev = eptdev->rpdev;

	struct device *dev = &eptdev->dev;



	if (eptdev->ept)

	mutex_lock(&eptdev->ept_lock);

	if (eptdev->ept) {

		mutex_unlock(&eptdev->ept_lock);

		return -EBUSY;

	}



	get_device(dev);
@@ -137,11 +140,13 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) 
	if (!ept) {

		dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);

		put_device(dev);

		mutex_unlock(&eptdev->ept_lock);

		return -EINVAL;

	}



	eptdev->ept = ept;

	filp->private_data = eptdev;

	mutex_unlock(&eptdev->ept_lock);



	return 0;

}