[PATCH v2 1/2] xen-netback: fix memory leaks on XenBus disconnect

[PATCH v2 1/2] xen-netback: fix memory leaks on XenBus disconnect

[Igor Druzhinin]

Eliminate memory leaks introduced several years ago by cleaning the
queue resources which are allocated on XenBus connection event. Namely, queue
structure array and pages used for IO rings.

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
---
 drivers/net/xen-netback/xenbus.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 6c57b02..3e99071 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -493,11 +493,20 @@ static int backend_create_xenvif(struct backend_info *be)
 static void backend_disconnect(struct backend_info *be)
 {
 	if (be->vif) {
+		unsigned int queue_index;
+
 		xen_unregister_watchers(be->vif);
 #ifdef CONFIG_DEBUG_FS
 		xenvif_debugfs_delif(be->vif);
 #endif /* CONFIG_DEBUG_FS */
 		xenvif_disconnect_data(be->vif);
+		for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
+			xenvif_deinit_queue(&be->vif->queues[queue_index]);
+
+		vfree(be->vif->queues);
+		be->vif->num_queues = 0;
+		be->vif->queues = NULL;
+
 		xenvif_disconnect_ctrl(be->vif);
 	}
 }
@@ -1026,6 +1035,8 @@ static void connect(struct backend_info *be)
 err:
 	if (be->vif->num_queues > 0)
 		xenvif_disconnect_data(be->vif); /* Clean up existing queues */
+	for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
+		xenvif_deinit_queue(&be->vif->queues[queue_index]);
 	vfree(be->vif->queues);
 	be->vif->queues = NULL;
 	be->vif->num_queues = 0;
-- 
1.8.3.1


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[PATCH v2 2/2] xen-netback: protect resource cleaning on XenBus disconnect

[Igor Druzhinin]

vif->lock is used to protect statistics gathering agents from using the
queue structure during cleaning.

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
---
 drivers/net/xen-netback/interface.c | 6 ++++--
 drivers/net/xen-netback/xenbus.c    | 2 ++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 41c69b3..c48252a 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -230,18 +230,18 @@ static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
 {
 	struct xenvif *vif = netdev_priv(dev);
 	struct xenvif_queue *queue = NULL;
-	unsigned int num_queues = vif->num_queues;
 	unsigned long rx_bytes = 0;
 	unsigned long rx_packets = 0;
 	unsigned long tx_bytes = 0;
 	unsigned long tx_packets = 0;
 	unsigned int index;
 
+	spin_lock(&vif->lock);
 	if (vif->queues == NULL)
 		goto out;
 
 	/* Aggregate tx and rx stats from each queue */
-	for (index = 0; index < num_queues; ++index) {
+	for (index = 0; index < vif->num_queues; ++index) {
 		queue = &vif->queues[index];
 		rx_bytes += queue->stats.rx_bytes;
 		rx_packets += queue->stats.rx_packets;
@@ -250,6 +250,8 @@ static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
 	}
 
 out:
+	spin_unlock(&vif->lock);
+
 	vif->dev->stats.rx_bytes = rx_bytes;
 	vif->dev->stats.rx_packets = rx_packets;
 	vif->dev->stats.tx_bytes = tx_bytes;
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 3e99071..d82cd71 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -503,9 +503,11 @@ static void backend_disconnect(struct backend_info *be)
 		for (queue_index = 0; queue_index < be->vif->num_queues; ++queue_index)
 			xenvif_deinit_queue(&be->vif->queues[queue_index]);
 
+		spin_lock(&be->vif->lock);
 		vfree(be->vif->queues);
 		be->vif->num_queues = 0;
 		be->vif->queues = NULL;
+		spin_unlock(&be->vif->lock);
 
 		xenvif_disconnect_ctrl(be->vif);
 	}
-- 
1.8.3.1


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Re: [PATCH v2 1/2] xen-netback: fix memory leaks on XenBus disconnect

[Paul Durrant]

> -----Original Message-----
> From: Igor Druzhinin [mailto:igor.druzhinin@citrix.com]
> Sent: 17 January 2017 20:50
> To: Wei Liu <wei.liu2@citrix.com>
> Cc: Paul Durrant <Paul.Durrant@citrix.com>; xen-devel@lists.xenproject.org;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Igor Druzhinin
> <igor.druzhinin@citrix.com>
> Subject: [PATCH v2 1/2] xen-netback: fix memory leaks on XenBus
> disconnect
> 
> Eliminate memory leaks introduced several years ago by cleaning the
> queue resources which are allocated on XenBus connection event. Namely,
> queue
> structure array and pages used for IO rings.
> 
> Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>

Reviewed-by: Paul Durrant <paul.durrant@citrix.com>

> ---
>  drivers/net/xen-netback/xenbus.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-
> netback/xenbus.c
> index 6c57b02..3e99071 100644
> --- a/drivers/net/xen-netback/xenbus.c
> +++ b/drivers/net/xen-netback/xenbus.c
> @@ -493,11 +493,20 @@ static int backend_create_xenvif(struct
> backend_info *be)
>  static void backend_disconnect(struct backend_info *be)
>  {
>  	if (be->vif) {
> +		unsigned int queue_index;
> +
>  		xen_unregister_watchers(be->vif);
>  #ifdef CONFIG_DEBUG_FS
>  		xenvif_debugfs_delif(be->vif);
>  #endif /* CONFIG_DEBUG_FS */
>  		xenvif_disconnect_data(be->vif);
> +		for (queue_index = 0; queue_index < be->vif-
> >num_queues; ++queue_index)
> +			xenvif_deinit_queue(&be->vif-
> >queues[queue_index]);
> +
> +		vfree(be->vif->queues);
> +		be->vif->num_queues = 0;
> +		be->vif->queues = NULL;
> +
>  		xenvif_disconnect_ctrl(be->vif);
>  	}
>  }
> @@ -1026,6 +1035,8 @@ static void connect(struct backend_info *be)
>  err:
>  	if (be->vif->num_queues > 0)
>  		xenvif_disconnect_data(be->vif); /* Clean up existing
> queues */
> +	for (queue_index = 0; queue_index < be->vif->num_queues;
> ++queue_index)
> +		xenvif_deinit_queue(&be->vif->queues[queue_index]);
>  	vfree(be->vif->queues);
>  	be->vif->queues = NULL;
>  	be->vif->num_queues = 0;
> --
> 1.8.3.1


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Re: [PATCH v2 1/2] xen-netback: fix memory leaks on XenBus disconnect

[Wei Liu]

On Tue, Jan 17, 2017 at 08:49:37PM +0000, Igor Druzhinin wrote:
> Eliminate memory leaks introduced several years ago by cleaning the
> queue resources which are allocated on XenBus connection event. Namely, queue
> structure array and pages used for IO rings.
> 
> Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

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Re: [PATCH v2 2/2] xen-netback: protect resource cleaning on XenBus disconnect

[Wei Liu]

On Tue, Jan 17, 2017 at 08:49:38PM +0000, Igor Druzhinin wrote:
> vif->lock is used to protect statistics gathering agents from using the
> queue structure during cleaning.
> 
> Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

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Re: [PATCH v2 2/2] xen-netback: protect resource cleaning on XenBus disconnect

[Paul Durrant]

> -----Original Message-----
> From: Igor Druzhinin [mailto:igor.druzhinin@citrix.com]
> Sent: 17 January 2017 20:50
> To: Wei Liu <wei.liu2@citrix.com>
> Cc: Paul Durrant <Paul.Durrant@citrix.com>; xen-devel@lists.xenproject.org;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Igor Druzhinin
> <igor.druzhinin@citrix.com>
> Subject: [PATCH v2 2/2] xen-netback: protect resource cleaning on XenBus
> disconnect
> 
> vif->lock is used to protect statistics gathering agents from using the
> queue structure during cleaning.
> 
> Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>

Reviewed-by: Paul Durrant <paul.durrant@citrix.com>

> ---
>  drivers/net/xen-netback/interface.c | 6 ++++--
>  drivers/net/xen-netback/xenbus.c    | 2 ++
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-
> netback/interface.c
> index 41c69b3..c48252a 100644
> --- a/drivers/net/xen-netback/interface.c
> +++ b/drivers/net/xen-netback/interface.c
> @@ -230,18 +230,18 @@ static struct net_device_stats
> *xenvif_get_stats(struct net_device *dev)
>  {
>  	struct xenvif *vif = netdev_priv(dev);
>  	struct xenvif_queue *queue = NULL;
> -	unsigned int num_queues = vif->num_queues;
>  	unsigned long rx_bytes = 0;
>  	unsigned long rx_packets = 0;
>  	unsigned long tx_bytes = 0;
>  	unsigned long tx_packets = 0;
>  	unsigned int index;
> 
> +	spin_lock(&vif->lock);
>  	if (vif->queues == NULL)
>  		goto out;
> 
>  	/* Aggregate tx and rx stats from each queue */
> -	for (index = 0; index < num_queues; ++index) {
> +	for (index = 0; index < vif->num_queues; ++index) {
>  		queue = &vif->queues[index];
>  		rx_bytes += queue->stats.rx_bytes;
>  		rx_packets += queue->stats.rx_packets;
> @@ -250,6 +250,8 @@ static struct net_device_stats
> *xenvif_get_stats(struct net_device *dev)
>  	}
> 
>  out:
> +	spin_unlock(&vif->lock);
> +
>  	vif->dev->stats.rx_bytes = rx_bytes;
>  	vif->dev->stats.rx_packets = rx_packets;
>  	vif->dev->stats.tx_bytes = tx_bytes;
> diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-
> netback/xenbus.c
> index 3e99071..d82cd71 100644
> --- a/drivers/net/xen-netback/xenbus.c
> +++ b/drivers/net/xen-netback/xenbus.c
> @@ -503,9 +503,11 @@ static void backend_disconnect(struct backend_info
> *be)
>  		for (queue_index = 0; queue_index < be->vif-
> >num_queues; ++queue_index)
>  			xenvif_deinit_queue(&be->vif-
> >queues[queue_index]);
> 
> +		spin_lock(&be->vif->lock);
>  		vfree(be->vif->queues);
>  		be->vif->num_queues = 0;
>  		be->vif->queues = NULL;
> +		spin_unlock(&be->vif->lock);
> 
>  		xenvif_disconnect_ctrl(be->vif);
>  	}
> --
> 1.8.3.1


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Re: [PATCH v2 0/2] xen-netback: fix memory leaks on XenBus disconnect

[David Miller]

From: Igor Druzhinin <igor.druzhinin@citrix.com>
Date: Tue, 17 Jan 2017 20:49:36 +0000

> Just split the initial patch in two as proposed by Wei.
> 
> Since the approach for locking netdev statistics is inconsistent (tends not
> to have any locking at all) accross the kernel we'd better to rely on our
> internal lock for this purpose.

Series applied, thanks.

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