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rpmsg: char: Add mutex protection for rpmsg_eptdev_open()

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[ Upstream commit abe13e9a56 ]

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: 964e8bedd5 ("rpmsg: char: Return an error if device already open")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1653104105-16779-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Shengjiu Wang 2022-05-21 11:35:05 +08:00 committed by Greg Kroah-Hartman
parent c81935d0e0
commit f061773b7b
1 changed files with 6 additions and 1 deletions
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7
drivers/rpmsg/rpmsg_char.c
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@ -127,8 +127,11 @@ 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);
@ -136,11 +139,13 @@ 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;
}