tree bd744cfa88df4de11ce5b6cc66139c0748f2e7f4
parent a299827d74e7ead4f1c438e26c473718d4847210
author Ohad Ben-Cohen <ohad@wizery.com> 1339072775 +0300
committer chrmhoffmann <chrmhoffmann@gmail.com> 1586074533 +0200

rpmsg: make sure inflight messages don't invoke just-removed callbacks

commit 15fd943af50dbc5f7f4de33835795c72595f7bf4 upstream.

When inbound messages arrive, rpmsg core looks up their associated
endpoint (by destination address) and then invokes their callback.

We've made sure that endpoints will never be de-allocated after they
were found by rpmsg core, but we also need to protect against the
(rare) scenario where the rpmsg driver was just removed, and its
callback function isn't available anymore.

This is achieved by introducing a callback mutex, which must be taken
before the callback is invoked, and, obviously, before it is removed.

Reported-by: Fernando Guzman Lugo <fernando.lugo@ti.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>