Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[Jason Wang]

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
Reported-by:syzbot+c0272972b01b872e6...@syzkaller.appspotmail.com
Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
Signed-off-by: Jason Wang

OK with this the only bug we have is where get user pages returns 0
(Reported-by:syzbot+6304bf97ef436580f...@syzkaller.appspotmail.com)





Thanks for the reminder.

I post a patch to avoid this.

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[Jason Wang]

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
Reported-by:syzbot+c0272972b01b872e6...@syzkaller.appspotmail.com
Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
Signed-off-by: Jason Wang

OK with this the only bug we have is where get user pages returns 0
(Reported-by:syzbot+6304bf97ef436580f...@syzkaller.appspotmail.com)





Thanks for the reminder.

I post a patch to avoid this.

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[Michael S. Tsirkin]

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 
> Reported-by: syzbot+c0272972b01b872e6...@syzkaller.appspotmail.com
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang 

OK with this the only bug we have is where get user pages returns 0
(Reported-by: syzbot+6304bf97ef436580f...@syzkaller.appspotmail.com)



> ---
> 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(>wait, 0, 0, poll_to_key(mask));
>   if (mask & EPOLLERR) {
> - if (poll->wqh)
> - remove_wait_queue(poll->wqh, >wait);
> + vhost_poll_stop(poll);
>   ret = -EINVAL;
>   }
>  
> -- 
> 2.7.4

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[Michael S. Tsirkin]

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 
> Reported-by: syzbot+c0272972b01b872e6...@syzkaller.appspotmail.com
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang 

OK with this the only bug we have is where get user pages returns 0
(Reported-by: syzbot+6304bf97ef436580f...@syzkaller.appspotmail.com)



> ---
> 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(>wait, 0, 0, poll_to_key(mask));
>   if (mask & EPOLLERR) {
> - if (poll->wqh)
> - remove_wait_queue(poll->wqh, >wait);
> + vhost_poll_stop(poll);
>   ret = -EINVAL;
>   }
>  
> -- 
> 2.7.4

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[David Miller]

From: Jason Wang 
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 
> Reported-by: syzbot+c0272972b01b872e6...@syzkaller.appspotmail.com
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang 
> ---
> Changes from V1:
> - tweak the commit log for to match the code

Applied and queued up for -stable, thank you.

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[David Miller]

From: Jason Wang 
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 
> Reported-by: syzbot+c0272972b01b872e6...@syzkaller.appspotmail.com
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang 
> ---
> Changes from V1:
> - tweak the commit log for to match the code

Applied and queued up for -stable, thank you.

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[Michael S. Tsirkin]

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 
> Reported-by: syzbot+c0272972b01b872e6...@syzkaller.appspotmail.com
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang 

Acked-by: Michael S. Tsirkin 

> ---
> 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(>wait, 0, 0, poll_to_key(mask));
>   if (mask & EPOLLERR) {
> - if (poll->wqh)
> - remove_wait_queue(poll->wqh, >wait);
> + vhost_poll_stop(poll);
>   ret = -EINVAL;
>   }
>  
> -- 
> 2.7.4

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[Michael S. Tsirkin]

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 
> Reported-by: syzbot+c0272972b01b872e6...@syzkaller.appspotmail.com
> Fixes: 2b8b328b61c79 ("vhost_net: handle polling errors when setting backend")
> Signed-off-by: Jason Wang 

Acked-by: Michael S. Tsirkin 

> ---
> 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(>wait, 0, 0, poll_to_key(mask));
>   if (mask & EPOLLERR) {
> - if (poll->wqh)
> - remove_wait_queue(poll->wqh, >wait);
> + vhost_poll_stop(poll);
>   ret = -EINVAL;
>   }
>  
> -- 
> 2.7.4

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[Darren Kenny]

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 
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 


---
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(>wait, 0, 0, poll_to_key(mask));
if (mask & EPOLLERR) {
-   if (poll->wqh)
-   remove_wait_queue(poll->wqh, >wait);
+   vhost_poll_stop(poll);
ret = -EINVAL;
}

--
2.7.4

Re: [PATCH net V2] vhost: correctly remove wait queue during poll failure

[Darren Kenny]

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 
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 


---
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(>wait, 0, 0, poll_to_key(mask));
if (mask & EPOLLERR) {
-   if (poll->wqh)
-   remove_wait_queue(poll->wqh, >wait);
+   vhost_poll_stop(poll);
ret = -EINVAL;
}

--
2.7.4

[PATCH net V2] vhost: correctly remove wait queue during poll failure

[Jason Wang]

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 
---
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(>wait, 0, 0, poll_to_key(mask));
if (mask & EPOLLERR) {
-   if (poll->wqh)
-   remove_wait_queue(poll->wqh, >wait);
+   vhost_poll_stop(poll);
ret = -EINVAL;
}
 
-- 
2.7.4

[PATCH net V2] vhost: correctly remove wait queue during poll failure

[Jason Wang]

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 
---
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(>wait, 0, 0, poll_to_key(mask));
if (mask & EPOLLERR) {
-   if (poll->wqh)
-   remove_wait_queue(poll->wqh, >wait);
+   vhost_poll_stop(poll);
ret = -EINVAL;
}
 
-- 
2.7.4