CVE-2022-50421

In the Linux kernel, the following vulnerability has been resolved:

rpmsg: char: Avoid double destroy of default endpoint

The rpmsg_dev_remove() in rpmsg_core is the place for releasing this default endpoint.

So need to avoid destroying the default endpoint in rpmsg_chrdev_eptdev_destroy(), this should be the same as rpmsg_eptdev_release(). Otherwise there will be double destroy issue that ept->refcount report warning:

refcount_t: underflow; use-after-free.

Call trace: refcount_warn_saturate+0xf8/0x150 virtio_rpmsg_destroy_ept+0xd4/0xec rpmsg_dev_remove+0x60/0x70

The issue can be reproduced by stopping remoteproc before closing the /dev/rpmsgX.

Moderate severity is assigned because exploitation is restricted to local privileged users and relies on specific race conditions during remote processor device shutdown. In typical Red Hat Enterprise Linux deployments, remote processor character devices are neither active nor present by default, limiting practical exposure. Successful exploitation requires stopping the remoteproc subsystem while an endpoint device is open, potentially causing a kernel panic or memory corruption.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.