Merge branch 'vsock-virtio-fixes'
Stefano Garzarella says:
====================
vsock/virtio: several fixes in the .probe() and .remove()
During the review of "[PATCH] vsock/virtio: Initialize core virtio vsock
before registering the driver", Stefan pointed out some possible issues
in the .probe() and .remove() callbacks of the virtio-vsock driver.
This series tries to solve these issues:
- Patch 1 adds RCU critical sections to avoid use-after-free of
'the_virtio_vsock' pointer.
- Patch 2 stops workers before to call vdev->config->reset(vdev) to
be sure that no one is accessing the device.
- Patch 3 moves the works flush at the end of the .remove() to avoid
use-after-free of 'vsock' object.
v3:
- Patch 1: use rcu_dereference_protected() to get the_virtio_vosck value in
the virtio_vsock_probe() [Jason]
v2: https://patchwork.kernel.org/cover/11022343/
v1: https://patchwork.kernel.org/cover/10964733/
Before this series the guest crashes in a few second. After this series the
test runs (~12h) without issues.
Tested on an SMP guest (-smp 4 -monitor tcp:127.0.0.1:1234,server,nowait)
with these scripts to stress the .probe()/.remove() path:
- guest
while true; do
cat /dev/urandom | nc-vsock -l 4321 > /dev/null &
cat /dev/urandom | nc-vsock -l 5321 > /dev/null &
cat /dev/urandom | nc-vsock -l 6321 > /dev/null &
cat /dev/urandom | nc-vsock -l 7321 > /dev/null &
wait
done
- host
while true; do
cat /dev/urandom | nc-vsock 3 4321 > /dev/null &
cat /dev/urandom | nc-vsock 3 5321 > /dev/null &
cat /dev/urandom | nc-vsock 3 6321 > /dev/null &
cat /dev/urandom | nc-vsock 3 7321 > /dev/null &
sleep 2
echo "device_del v1" | nc 127.0.0.1 1234
sleep 1
echo "device_add vhost-vsock-pci,id=v1,guest-cid=3" | nc 127.0.0.1 1234
sleep 1
done
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller
commit
3f4957eb6c
@ -38,6 +38,7 @@ struct virtio_vsock {
|
||||
* must be accessed with tx_lock held.
|
||||
*/
|
||||
struct mutex tx_lock;
|
||||
bool tx_run;
|
||||
|
||||
struct work_struct send_pkt_work;
|
||||
spinlock_t send_pkt_list_lock;
|
||||
@ -53,6 +54,7 @@ struct virtio_vsock {
|
||||
* must be accessed with rx_lock held.
|
||||
*/
|
||||
struct mutex rx_lock;
|
||||
bool rx_run;
|
||||
int rx_buf_nr;
|
||||
int rx_buf_max_nr;
|
||||
|
||||
@ -60,24 +62,28 @@ struct virtio_vsock {
|
||||
* vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held.
|
||||
*/
|
||||
struct mutex event_lock;
|
||||
bool event_run;
|
||||
struct virtio_vsock_event event_list[8];
|
||||
|
||||
u32 guest_cid;
|
||||
};
|
||||
|
||||
static struct virtio_vsock *virtio_vsock_get(void)
|
||||
{
|
||||
return the_virtio_vsock;
|
||||
}
|
||||
|
||||
static u32 virtio_transport_get_local_cid(void)
|
||||
{
|
||||
struct virtio_vsock *vsock = virtio_vsock_get();
|
||||
struct virtio_vsock *vsock;
|
||||
u32 ret;
|
||||
|
||||
if (!vsock)
|
||||
return VMADDR_CID_ANY;
|
||||
rcu_read_lock();
|
||||
vsock = rcu_dereference(the_virtio_vsock);
|
||||
if (!vsock) {
|
||||
ret = VMADDR_CID_ANY;
|
||||
goto out_rcu;
|
||||
}
|
||||
|
||||
return vsock->guest_cid;
|
||||
ret = vsock->guest_cid;
|
||||
out_rcu:
|
||||
rcu_read_unlock();
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void virtio_transport_loopback_work(struct work_struct *work)
|
||||
@ -91,6 +97,10 @@ static void virtio_transport_loopback_work(struct work_struct *work)
|
||||
spin_unlock_bh(&vsock->loopback_list_lock);
|
||||
|
||||
mutex_lock(&vsock->rx_lock);
|
||||
|
||||
if (!vsock->rx_run)
|
||||
goto out;
|
||||
|
||||
while (!list_empty(&pkts)) {
|
||||
struct virtio_vsock_pkt *pkt;
|
||||
|
||||
@ -99,6 +109,7 @@ static void virtio_transport_loopback_work(struct work_struct *work)
|
||||
|
||||
virtio_transport_recv_pkt(pkt);
|
||||
}
|
||||
out:
|
||||
mutex_unlock(&vsock->rx_lock);
|
||||
}
|
||||
|
||||
@ -127,6 +138,9 @@ virtio_transport_send_pkt_work(struct work_struct *work)
|
||||
|
||||
mutex_lock(&vsock->tx_lock);
|
||||
|
||||
if (!vsock->tx_run)
|
||||
goto out;
|
||||
|
||||
vq = vsock->vqs[VSOCK_VQ_TX];
|
||||
|
||||
for (;;) {
|
||||
@ -185,6 +199,7 @@ virtio_transport_send_pkt_work(struct work_struct *work)
|
||||
if (added)
|
||||
virtqueue_kick(vq);
|
||||
|
||||
out:
|
||||
mutex_unlock(&vsock->tx_lock);
|
||||
|
||||
if (restart_rx)
|
||||
@ -197,14 +212,18 @@ virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
|
||||
struct virtio_vsock *vsock;
|
||||
int len = pkt->len;
|
||||
|
||||
vsock = virtio_vsock_get();
|
||||
rcu_read_lock();
|
||||
vsock = rcu_dereference(the_virtio_vsock);
|
||||
if (!vsock) {
|
||||
virtio_transport_free_pkt(pkt);
|
||||
return -ENODEV;
|
||||
len = -ENODEV;
|
||||
goto out_rcu;
|
||||
}
|
||||
|
||||
if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid)
|
||||
return virtio_transport_send_pkt_loopback(vsock, pkt);
|
||||
if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid) {
|
||||
len = virtio_transport_send_pkt_loopback(vsock, pkt);
|
||||
goto out_rcu;
|
||||
}
|
||||
|
||||
if (pkt->reply)
|
||||
atomic_inc(&vsock->queued_replies);
|
||||
@ -214,6 +233,9 @@ virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
|
||||
spin_unlock_bh(&vsock->send_pkt_list_lock);
|
||||
|
||||
queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work);
|
||||
|
||||
out_rcu:
|
||||
rcu_read_unlock();
|
||||
return len;
|
||||
}
|
||||
|
||||
@ -222,12 +244,14 @@ virtio_transport_cancel_pkt(struct vsock_sock *vsk)
|
||||
{
|
||||
struct virtio_vsock *vsock;
|
||||
struct virtio_vsock_pkt *pkt, *n;
|
||||
int cnt = 0;
|
||||
int cnt = 0, ret;
|
||||
LIST_HEAD(freeme);
|
||||
|
||||
vsock = virtio_vsock_get();
|
||||
rcu_read_lock();
|
||||
vsock = rcu_dereference(the_virtio_vsock);
|
||||
if (!vsock) {
|
||||
return -ENODEV;
|
||||
ret = -ENODEV;
|
||||
goto out_rcu;
|
||||
}
|
||||
|
||||
spin_lock_bh(&vsock->send_pkt_list_lock);
|
||||
@ -255,7 +279,11 @@ virtio_transport_cancel_pkt(struct vsock_sock *vsk)
|
||||
queue_work(virtio_vsock_workqueue, &vsock->rx_work);
|
||||
}
|
||||
|
||||
return 0;
|
||||
ret = 0;
|
||||
|
||||
out_rcu:
|
||||
rcu_read_unlock();
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
|
||||
@ -307,6 +335,10 @@ static void virtio_transport_tx_work(struct work_struct *work)
|
||||
|
||||
vq = vsock->vqs[VSOCK_VQ_TX];
|
||||
mutex_lock(&vsock->tx_lock);
|
||||
|
||||
if (!vsock->tx_run)
|
||||
goto out;
|
||||
|
||||
do {
|
||||
struct virtio_vsock_pkt *pkt;
|
||||
unsigned int len;
|
||||
@ -317,6 +349,8 @@ static void virtio_transport_tx_work(struct work_struct *work)
|
||||
added = true;
|
||||
}
|
||||
} while (!virtqueue_enable_cb(vq));
|
||||
|
||||
out:
|
||||
mutex_unlock(&vsock->tx_lock);
|
||||
|
||||
if (added)
|
||||
@ -345,6 +379,9 @@ static void virtio_transport_rx_work(struct work_struct *work)
|
||||
|
||||
mutex_lock(&vsock->rx_lock);
|
||||
|
||||
if (!vsock->rx_run)
|
||||
goto out;
|
||||
|
||||
do {
|
||||
virtqueue_disable_cb(vq);
|
||||
for (;;) {
|
||||
@ -454,6 +491,9 @@ static void virtio_transport_event_work(struct work_struct *work)
|
||||
|
||||
mutex_lock(&vsock->event_lock);
|
||||
|
||||
if (!vsock->event_run)
|
||||
goto out;
|
||||
|
||||
do {
|
||||
struct virtio_vsock_event *event;
|
||||
unsigned int len;
|
||||
@ -468,7 +508,7 @@ static void virtio_transport_event_work(struct work_struct *work)
|
||||
} while (!virtqueue_enable_cb(vq));
|
||||
|
||||
virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]);
|
||||
|
||||
out:
|
||||
mutex_unlock(&vsock->event_lock);
|
||||
}
|
||||
|
||||
@ -565,7 +605,8 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
|
||||
return ret;
|
||||
|
||||
/* Only one virtio-vsock device per guest is supported */
|
||||
if (the_virtio_vsock) {
|
||||
if (rcu_dereference_protected(the_virtio_vsock,
|
||||
lockdep_is_held(&the_virtio_vsock_mutex))) {
|
||||
ret = -EBUSY;
|
||||
goto out;
|
||||
}
|
||||
@ -590,8 +631,6 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
|
||||
vsock->rx_buf_max_nr = 0;
|
||||
atomic_set(&vsock->queued_replies, 0);
|
||||
|
||||
vdev->priv = vsock;
|
||||
the_virtio_vsock = vsock;
|
||||
mutex_init(&vsock->tx_lock);
|
||||
mutex_init(&vsock->rx_lock);
|
||||
mutex_init(&vsock->event_lock);
|
||||
@ -605,14 +644,23 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
|
||||
INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
|
||||
INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);
|
||||
|
||||
mutex_lock(&vsock->tx_lock);
|
||||
vsock->tx_run = true;
|
||||
mutex_unlock(&vsock->tx_lock);
|
||||
|
||||
mutex_lock(&vsock->rx_lock);
|
||||
virtio_vsock_rx_fill(vsock);
|
||||
vsock->rx_run = true;
|
||||
mutex_unlock(&vsock->rx_lock);
|
||||
|
||||
mutex_lock(&vsock->event_lock);
|
||||
virtio_vsock_event_fill(vsock);
|
||||
vsock->event_run = true;
|
||||
mutex_unlock(&vsock->event_lock);
|
||||
|
||||
vdev->priv = vsock;
|
||||
rcu_assign_pointer(the_virtio_vsock, vsock);
|
||||
|
||||
mutex_unlock(&the_virtio_vsock_mutex);
|
||||
return 0;
|
||||
|
||||
@ -627,15 +675,33 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
|
||||
struct virtio_vsock *vsock = vdev->priv;
|
||||
struct virtio_vsock_pkt *pkt;
|
||||
|
||||
flush_work(&vsock->loopback_work);
|
||||
flush_work(&vsock->rx_work);
|
||||
flush_work(&vsock->tx_work);
|
||||
flush_work(&vsock->event_work);
|
||||
flush_work(&vsock->send_pkt_work);
|
||||
mutex_lock(&the_virtio_vsock_mutex);
|
||||
|
||||
vdev->priv = NULL;
|
||||
rcu_assign_pointer(the_virtio_vsock, NULL);
|
||||
synchronize_rcu();
|
||||
|
||||
/* Reset all connected sockets when the device disappear */
|
||||
vsock_for_each_connected_socket(virtio_vsock_reset_sock);
|
||||
|
||||
/* Stop all work handlers to make sure no one is accessing the device,
|
||||
* so we can safely call vdev->config->reset().
|
||||
*/
|
||||
mutex_lock(&vsock->rx_lock);
|
||||
vsock->rx_run = false;
|
||||
mutex_unlock(&vsock->rx_lock);
|
||||
|
||||
mutex_lock(&vsock->tx_lock);
|
||||
vsock->tx_run = false;
|
||||
mutex_unlock(&vsock->tx_lock);
|
||||
|
||||
mutex_lock(&vsock->event_lock);
|
||||
vsock->event_run = false;
|
||||
mutex_unlock(&vsock->event_lock);
|
||||
|
||||
/* Flush all device writes and interrupts, device will not use any
|
||||
* more buffers.
|
||||
*/
|
||||
vdev->config->reset(vdev);
|
||||
|
||||
mutex_lock(&vsock->rx_lock);
|
||||
@ -666,12 +732,20 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
|
||||
}
|
||||
spin_unlock_bh(&vsock->loopback_list_lock);
|
||||
|
||||
mutex_lock(&the_virtio_vsock_mutex);
|
||||
the_virtio_vsock = NULL;
|
||||
mutex_unlock(&the_virtio_vsock_mutex);
|
||||
|
||||
/* Delete virtqueues and flush outstanding callbacks if any */
|
||||
vdev->config->del_vqs(vdev);
|
||||
|
||||
/* Other works can be queued before 'config->del_vqs()', so we flush
|
||||
* all works before to free the vsock object to avoid use after free.
|
||||
*/
|
||||
flush_work(&vsock->loopback_work);
|
||||
flush_work(&vsock->rx_work);
|
||||
flush_work(&vsock->tx_work);
|
||||
flush_work(&vsock->event_work);
|
||||
flush_work(&vsock->send_pkt_work);
|
||||
|
||||
mutex_unlock(&the_virtio_vsock_mutex);
|
||||
|
||||
kfree(vsock);
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user