Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure
flat view
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2018-03-29 04:20:36
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On Tue, Mar 27, 2018 at 08:50:52PM +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 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 <redacted>
Reported-by: syzbot+c0272972b01b872e604a@syzkaller.appspotmail.com
Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
Signed-off-by: Jason Wang <redacted>OK with this the only bug we have is where get user pages returns 0 (Reported-by: syzbot+6304bf97ef436580fede@syzkaller.appspotmail.com)
quoted hunk ↗ jump to hunk
--- Changes from V1: - tweak the commit log for to match the code --- 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