2022-03-28 15:48:52

by Shengjiu Wang

[permalink] [raw]
Subject: [PATCH] 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,

Signed-off-by: Shengjiu Wang <[email protected]>
---
drivers/rpmsg/rpmsg_char.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

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;
}
--
2.17.1