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 <[email protected]>
Reported-by: [email protected]
Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
Signed-off-by: Jason Wang <[email protected]>
---
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
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 <[email protected]>
>Reported-by: [email protected]
>Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
>Signed-off-by: Jason Wang <[email protected]>
Reviewed-by: Darren Kenny <[email protected]>
>---
>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
>
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 <[email protected]>
> Reported-by: [email protected]
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
> ---
> 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
From: Jason Wang <[email protected]>
Date: Tue, 27 Mar 2018 20:50:52 +0800
> 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 <[email protected]>
> Reported-by: [email protected]
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang <[email protected]>
> ---
> Changes from V1:
> - tweak the commit log for to match the code
Applied and queued up for -stable, thank you.
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 <[email protected]>
> Reported-by: [email protected]
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang <[email protected]>
OK with this the only bug we have is where get user pages returns 0
(Reported-by: [email protected])
> ---
> 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
On 2018年03月29日 12:20, Michael S. Tsirkin wrote:
> 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<[email protected]>
>> Reported-by:[email protected]
>> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
>> Signed-off-by: Jason Wang<[email protected]>
> OK with this the only bug we have is where get user pages returns 0
> (Reported-by:[email protected])
>
>
>
Thanks for the reminder.
I post a patch to avoid this.