On 2018年03月27日 17:28, Darren Kenny wrote:
Hi Jason,
On Tue, Mar 27, 2018 at 11:47:22AM +0800, Jason Wang wrote:
We tried to remove vq poll from wait queue, but do not check whether
or not it was in a list before. This will lead double free. Fixing
this by checking poll->wqh to make sure it was in a list.
This text seems at odds with the code below, instead of checking
poll-whq, you are removing that check...
Maybe the text needs rewording?
Yes, I admit it's bad, thanks for pointing out.
How about:
"Fixing this by switching to use vhost_poll_stop() which zeros poll->wqh
after removing poll from waitqueue to make sure it won't be freed twice."
Thanks
Thanks,
Darren.
Reported-by: syzbot+c0272972b01b872e604a@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting
backend")
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 1b3e8d2d..5d5a9d9 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -212,8 +212,7 @@ int vhost_poll_start(struct vhost_poll *poll,
struct file *file)
if (mask)
vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
if (mask & EPOLLERR) {
- if (poll->wqh)
- remove_wait_queue(poll->wqh, &poll->wait);
+ vhost_poll_stop(poll);
ret = -EINVAL;
}
--
2.7.4
