From: Shengjiu Wang shengjiu.wang@nxp.com
[ Upstream commit abe13e9a561d6b3e82b21362c0d6dd3ecd8a5b13 ]
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 shengjiu.wang@nxp.com Link: https://lore.kernel.org/r/1653104105-16779-1-git-send-email-shengjiu.wang@nx... Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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; }