diff options
author | Jason Wang <jasowang@redhat.com> | 2013-01-28 01:05:18 +0000 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2013-01-29 15:43:03 -0500 |
commit | 2b8b328b61c799957a456a5a8dab8cc7dea68575 (patch) | |
tree | 7f782227156eb9aca1a0f3c9cd097e778bc8b7af /drivers/vhost/vhost.c | |
parent | 692a998b908ae4c612d95d1f5f5adae03eca2b79 (diff) |
vhost_net: handle polling errors when setting backend
Currently, the polling errors were ignored, which can lead following issues:
- vhost remove itself unconditionally from waitqueue when stopping the poll,
this may crash the kernel since the previous attempt of starting may fail to
add itself to the waitqueue
- userspace may think the backend were successfully set even when the polling
failed.
Solve this by:
- check poll->wqh before trying to remove from waitqueue
- report polling errors in vhost_poll_start(), tx_poll_start(), the return value
will be checked and returned when userspace want to set the backend
After this fix, there still could be a polling failure after backend is set, it
will addressed by the next patch.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/vhost/vhost.c')
-rw-r--r-- | drivers/vhost/vhost.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 34389f75fe65..9759249e6d90 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -77,26 +77,38 @@ void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, init_poll_funcptr(&poll->table, vhost_poll_func); poll->mask = mask; poll->dev = dev; + poll->wqh = NULL; vhost_work_init(&poll->work, fn); } /* Start polling a file. We add ourselves to file's wait queue. The caller must * keep a reference to a file until after vhost_poll_stop is called. */ -void vhost_poll_start(struct vhost_poll *poll, struct file *file) +int vhost_poll_start(struct vhost_poll *poll, struct file *file) { unsigned long mask; + int ret = 0; mask = file->f_op->poll(file, &poll->table); if (mask) vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); + if (mask & POLLERR) { + if (poll->wqh) + remove_wait_queue(poll->wqh, &poll->wait); + ret = -EINVAL; + } + + return ret; } /* Stop polling a file. After this function returns, it becomes safe to drop the * file reference. You must also flush afterwards. */ void vhost_poll_stop(struct vhost_poll *poll) { - remove_wait_queue(poll->wqh, &poll->wait); + if (poll->wqh) { + remove_wait_queue(poll->wqh, &poll->wait); + poll->wqh = NULL; + } } static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work, @@ -792,7 +804,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) fput(filep); if (pollstart && vq->handle_kick) - vhost_poll_start(&vq->poll, vq->kick); + r = vhost_poll_start(&vq->poll, vq->kick); mutex_unlock(&vq->mutex); |