From abe13e9a561d6b3e82b21362c0d6dd3ecd8a5b13 Mon Sep 17 00:00:00 2001 From: Shengjiu Wang Date: Sat, 21 May 2022 11:35:05 +0800 Subject: 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: 964e8bedd5a1 ("rpmsg: char: Return an error if device already open") Signed-off-by: Shengjiu Wang Link: https://lore.kernel.org/r/1653104105-16779-1-git-send-email-shengjiu.wang@nxp.com Signed-off-by: Mathieu Poirier --- drivers/rpmsg/rpmsg_char.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/rpmsg') diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index b6183d4f62a2..4f2189111494 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -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; } -- cgit v1.2.3-59-g8ed1b