[PATCH v8 01/17] vhost: create worker at end of vhost_dev_set_owner
From: Mike Christie <michael.christie@oracle.com>
Date: 2023-06-13 01:33:22
Subsystem:
the rest, virtio host (vhost) · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
vsock can start queueing work after VHOST_VSOCK_SET_GUEST_CID, so after we have called vhost_worker_create it can be calling vhost_work_queue and trying to access the vhost worker/task. If vhost_dev_alloc_iovecs fails, then vhost_worker_free could free the worker/task from under vsock. This moves vhost_worker_create to the end of vhost_dev_set_owner where we know we can no longer fail in that path. If it fails after the VHOST_SET_OWNER and userspace closes the device, then the normal vsock release handling will do the right thing. Signed-off-by: Mike Christie <michael.christie@oracle.com> --- drivers/vhost/vhost.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 60c9ebd629dd..82966ffb4a5c 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c@@ -572,20 +572,27 @@ long vhost_dev_set_owner(struct vhost_dev *dev) vhost_attach_mm(dev); + err = vhost_dev_alloc_iovecs(dev); + if (err) + goto err_iovecs; + if (dev->use_worker) { + /* + * This should be done last, because vsock can queue work + * before VHOST_SET_OWNER so it simplifies the failure path + * below since we don't have to worry about vsock queueing + * while we free the worker. + */ err = vhost_worker_create(dev); if (err) goto err_worker; } - err = vhost_dev_alloc_iovecs(dev); - if (err) - goto err_iovecs; - return 0; -err_iovecs: - vhost_worker_free(dev); + err_worker: + vhost_dev_free_iovecs(dev); +err_iovecs: vhost_detach_mm(dev); err_mm: return err;
--
2.25.1
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