[PATCH 3.18 109/121] vhost: correctly remove wait queue during poll failure

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

--

From: Jason Wang 


[ Upstream commit dc6455a71c7fc5117977e197f67f71b49f27baba ]

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+c0272972b01b872e6...@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 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/vhost/vhost.c |3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -96,8 +96,7 @@ int vhost_poll_start(struct vhost_poll *
if (mask)
vhost_poll_wakeup(>wait, 0, 0, (void *)mask);
if (mask & POLLERR) {
-   if (poll->wqh)
-   remove_wait_queue(poll->wqh, >wait);
+   vhost_poll_stop(poll);
ret = -EINVAL;
}
 

[PATCH 3.18 109/121] vhost: correctly remove wait queue during poll failure

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

--

From: Jason Wang 


[ Upstream commit dc6455a71c7fc5117977e197f67f71b49f27baba ]

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+c0272972b01b872e6...@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 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/vhost/vhost.c |3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -96,8 +96,7 @@ int vhost_poll_start(struct vhost_poll *
if (mask)
vhost_poll_wakeup(>wait, 0, 0, (void *)mask);
if (mask & POLLERR) {
-   if (poll->wqh)
-   remove_wait_queue(poll->wqh, >wait);
+   vhost_poll_stop(poll);
ret = -EINVAL;
}