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authorOhad Ben-Cohen <ohad@wizery.com>2012-06-07 15:39:35 +0300
committerOhad Ben-Cohen <ohad@wizery.com>2012-07-04 11:51:59 +0300
commit15fd943af50dbc5f7f4de33835795c72595f7bf4 (patch)
treeb35e37da3edf0b0166f14cf1d71e665d506b7fdf /drivers/rpmsg
parent5a081caa0414b9bbb82c17ffab9d6fe66edbb72f (diff)
downloadlinux-linaro-stable-15fd943af50dbc5f7f4de33835795c72595f7bf4.tar.gz
rpmsg: make sure inflight messages don't invoke just-removed callbacks
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. Cc: stable <stable@vger.kernel.org> Reported-by: Fernando Guzman Lugo <fernando.lugo@ti.com> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Diffstat (limited to 'drivers/rpmsg')
-rw-r--r--drivers/rpmsg/virtio_rpmsg_bus.c25
1 files changed, 19 insertions, 6 deletions
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 9623327ba509..39d3aa41adda 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -227,6 +227,7 @@ static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
}
kref_init(&ept->refcount);
+ mutex_init(&ept->cb_lock);
ept->rpdev = rpdev;
ept->cb = cb;
@@ -324,10 +325,16 @@ EXPORT_SYMBOL(rpmsg_create_ept);
static void
__rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
{
+ /* make sure new inbound messages can't find this ept anymore */
mutex_lock(&vrp->endpoints_lock);
idr_remove(&vrp->endpoints, ept->addr);
mutex_unlock(&vrp->endpoints_lock);
+ /* make sure in-flight inbound messages won't invoke cb anymore */
+ mutex_lock(&ept->cb_lock);
+ ept->cb = NULL;
+ mutex_unlock(&ept->cb_lock);
+
kref_put(&ept->refcount, __ept_release);
}
@@ -821,14 +828,20 @@ static void rpmsg_recv_done(struct virtqueue *rvq)
mutex_unlock(&vrp->endpoints_lock);
- if (ept && ept->cb)
- ept->cb(ept->rpdev, msg->data, msg->len, ept->priv, msg->src);
- else
- dev_warn(dev, "msg received with no recepient\n");
+ if (ept) {
+ /* make sure ept->cb doesn't go away while we use it */
+ mutex_lock(&ept->cb_lock);
- /* farewell, ept, we don't need you anymore */
- if (ept)
+ if (ept->cb)
+ ept->cb(ept->rpdev, msg->data, msg->len, ept->priv,
+ msg->src);
+
+ mutex_unlock(&ept->cb_lock);
+
+ /* farewell, ept, we don't need you anymore */
kref_put(&ept->refcount, __ept_release);
+ } else
+ dev_warn(dev, "msg received with no recepient\n");
/* publish the real size of the buffer */
sg_init_one(&sg, msg, RPMSG_BUF_SIZE);