From dc6455a71c7fc5117977e197f67f71b49f27baba Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Tue, 27 Mar 2018 20:50:52 +0800 Subject: [PATCH] vhost: correctly remove wait queue during poll failure 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 switching to use vhost_poll_stop() which zeros poll->wqh after removing poll from waitqueue to make sure it won't be freed twice. Cc: Darren Kenny Reported-by: syzbot+c0272972b01b872e604a@syzkaller.appspotmail.com Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend") Signed-off-by: Jason Wang Reviewed-by: Darren Kenny Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- 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 1b3e8d2d5c8b..5d5a9d9e66d3 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; }