6.1-stable review patch. If anyone has any objections, please let me know.
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From: Jason Wang jasowang@redhat.com
[ Upstream commit 02e9e9366fefe461719da5d173385b6685f70319 ]
We used to call irq_bypass_unregister_producer() in vhost_vdpa_setup_vq_irq() which is problematic as we don't know if the token pointer is still valid or not.
Actually, we use the eventfd_ctx as the token so the life cycle of the token should be bound to the VHOST_SET_VRING_CALL instead of vhost_vdpa_setup_vq_irq() which could be called by set_status().
Fixing this by setting up irq bypass producer's token when handling VHOST_SET_VRING_CALL and un-registering the producer before calling vhost_vring_ioctl() to prevent a possible use after free as eventfd could have been released in vhost_vring_ioctl(). And such registering and unregistering will only be done if DRIVER_OK is set.
Reported-by: Dragos Tatulea dtatulea@nvidia.com Tested-by: Dragos Tatulea dtatulea@nvidia.com Reviewed-by: Dragos Tatulea dtatulea@nvidia.com Fixes: 2cf1ba9a4d15 ("vhost_vdpa: implement IRQ offloading in vhost_vdpa") Signed-off-by: Jason Wang jasowang@redhat.com Message-Id: 20240816031900.18013-1-jasowang@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vhost/vdpa.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index ef9e845a5a5c5..59587f9880d3c 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -191,11 +191,9 @@ static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid) if (irq < 0) return;
- irq_bypass_unregister_producer(&vq->call_ctx.producer); if (!vq->call_ctx.ctx) return;
- vq->call_ctx.producer.token = vq->call_ctx.ctx; vq->call_ctx.producer.irq = irq; ret = irq_bypass_register_producer(&vq->call_ctx.producer); if (unlikely(ret)) @@ -571,6 +569,14 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, vq->last_avail_idx = vq_state.split.avail_index; } break; + case VHOST_SET_VRING_CALL: + if (vq->call_ctx.ctx) { + if (ops->get_status(vdpa) & + VIRTIO_CONFIG_S_DRIVER_OK) + vhost_vdpa_unsetup_vq_irq(v, idx); + vq->call_ctx.producer.token = NULL; + } + break; }
r = vhost_vring_ioctl(&v->vdev, cmd, argp); @@ -603,13 +609,16 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd, cb.callback = vhost_vdpa_virtqueue_cb; cb.private = vq; cb.trigger = vq->call_ctx.ctx; + vq->call_ctx.producer.token = vq->call_ctx.ctx; + if (ops->get_status(vdpa) & + VIRTIO_CONFIG_S_DRIVER_OK) + vhost_vdpa_setup_vq_irq(v, idx); } else { cb.callback = NULL; cb.private = NULL; cb.trigger = NULL; } ops->set_vq_cb(vdpa, idx, &cb); - vhost_vdpa_setup_vq_irq(v, idx); break;
case VHOST_SET_VRING_NUM: @@ -1235,6 +1244,7 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep) for (i = 0; i < nvqs; i++) { vqs[i] = &v->vqs[i]; vqs[i]->handle_kick = handle_vq_kick; + vqs[i]->call_ctx.ctx = NULL; } vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false, vhost_vdpa_process_iotlb_msg);