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().
Fixes: 2cf1ba9a4d15 ("vhost_vdpa: implement IRQ offloading in vhost_vdpa")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
Note for Dragos: Please check whether this fixes your issue. I
slightly test it with vp_vdpa in L2.
---
drivers/vhost/vdpa.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index e31ec9ebc4ce..388226a48bcc 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -209,11 +209,9 @@ 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))
@@ -709,6 +707,12 @@ 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) {
+ vhost_vdpa_unsetup_vq_irq(v, idx);
+ vq->call_ctx.producer.token = NULL;
+ }
+ break;
}
r = vhost_vring_ioctl(&v->vdev, cmd, argp);
@@ -747,13 +751,14 @@ 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;
+ 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:
@@ -1419,6 +1424,7 @@ 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);
--
2.31.1
