diff options
| author | Deepak Kumar Singh <quic_deesin@quicinc.com> | 2022-09-19 13:53:59 +0300 |
|---|---|---|
| committer | Bjorn Andersson <andersson@kernel.org> | 2022-12-28 18:54:03 +0300 |
| commit | 17b88a2050e9d1f89a53562f2adb709a8959e763 (patch) | |
| tree | cfefb39fc41234e34b646276dd9e21f48e7d8f30 /drivers/rpmsg | |
| parent | d2ff0f84c1156dfd3646a4ca682b38413b409aa0 (diff) | |
| download | linux-17b88a2050e9d1f89a53562f2adb709a8959e763.tar.xz | |
rpmsg: char: Add lock to avoid race when rpmsg device is released
When remote host goes down glink char device channel is freed and
associated rpdev is destroyed through rpmsg_chrdev_eptdev_destroy(),
At the same time user space apps can still try to open/poll rpmsg
char device which will result in calling rpmsg_create_ept()/rpmsg_poll().
These functions will try to reference rpdev which has already been freed
through rpmsg_chrdev_eptdev_destroy().
File operation functions and device removal function must be protected
with lock. This patch adds existing ept lock in remove function as well.
Signed-off-by: Deepak Kumar Singh <quic_deesin@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/1663584840-15762-2-git-send-email-quic_deesin@quicinc.com
Diffstat (limited to 'drivers/rpmsg')
| -rw-r--r-- | drivers/rpmsg/rpmsg_char.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index 3e0b8f3496ed..a271fceb16f4 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -75,6 +75,7 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev); mutex_lock(&eptdev->ept_lock); + eptdev->rpdev = NULL; if (eptdev->ept) { /* The default endpoint is released by the rpmsg core */ if (!eptdev->default_ept) @@ -128,6 +129,11 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) return -EBUSY; } + if (!eptdev->rpdev) { + mutex_unlock(&eptdev->ept_lock); + return -ENETRESET; + } + get_device(dev); /* @@ -279,7 +285,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait) if (!skb_queue_empty(&eptdev->queue)) mask |= EPOLLIN | EPOLLRDNORM; + mutex_lock(&eptdev->ept_lock); mask |= rpmsg_poll(eptdev->ept, filp, wait); + mutex_unlock(&eptdev->ept_lock); return mask; } |