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* [PATCH] datapath: Avoid using stack larger than 1024.
@ 2017-06-27  9:20 Tonghao Zhang
  2017-06-27 21:19 ` Pravin Shelar
  0 siblings, 1 reply; 4+ messages in thread
From: Tonghao Zhang @ 2017-06-27  9:20 UTC (permalink / raw)
  To: netdev; +Cc: Tonghao Zhang

When compiling OvS-master on 4.4.0-81 kernel,
there is a warning:

    CC [M]  /root/ovs/datapath/linux/datapath.o
    /root/ovs/datapath/linux/datapath.c: In function
    ‘ovs_flow_cmd_set’:
    /root/ovs/datapath/linux/datapath.c:1221:1: warning:
    the frame size of 1040 bytes is larger than 1024 bytes
    [-Wframe-larger-than=]

This patch use kmalloc to malloc mem for sw_flow_mask and
avoid using stack.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
---
 net/openvswitch/datapath.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index c85029c..da8cd68 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -1107,7 +1107,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 	struct ovs_header *ovs_header = info->userhdr;
 	struct sw_flow_key key;
 	struct sw_flow *flow;
-	struct sw_flow_mask mask;
+	struct sw_flow_mask *mask;
 	struct sk_buff *reply = NULL;
 	struct datapath *dp;
 	struct sw_flow_actions *old_acts = NULL, *acts = NULL;
@@ -1120,7 +1120,11 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 
 	ufid_present = ovs_nla_get_ufid(&sfid, a[OVS_FLOW_ATTR_UFID], log);
 	if (a[OVS_FLOW_ATTR_KEY]) {
-		ovs_match_init(&match, &key, true, &mask);
+		mask = kmalloc(sizeof(struct sw_flow_mask), GFP_KERNEL);
+		if (!mask)
+			return -ENOMEM;
+
+		ovs_match_init(&match, &key, true, mask);
 		error = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY],
 					  a[OVS_FLOW_ATTR_MASK], log);
 	} else if (!ufid_present) {
@@ -1141,7 +1145,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 		}
 
 		acts = get_flow_actions(net, a[OVS_FLOW_ATTR_ACTIONS], &key,
-					&mask, log);
+					mask, log);
 		if (IS_ERR(acts)) {
 			error = PTR_ERR(acts);
 			goto error;
@@ -1216,6 +1220,7 @@ err_unlock_ovs:
 err_kfree_acts:
 	ovs_nla_free_flow_actions(acts);
 error:
+	kfree(mask);
 	return error;
 }
 
-- 
1.8.3.1

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH] datapath: Avoid using stack larger than 1024.
  2017-06-27  9:20 [PATCH] datapath: Avoid using stack larger than 1024 Tonghao Zhang
@ 2017-06-27 21:19 ` Pravin Shelar
  0 siblings, 0 replies; 4+ messages in thread
From: Pravin Shelar @ 2017-06-27 21:19 UTC (permalink / raw)
  To: Tonghao Zhang; +Cc: Linux Kernel Network Developers

On Tue, Jun 27, 2017 at 2:20 AM, Tonghao Zhang <xiangxia.m.yue@gmail.com> wrote:
> When compiling OvS-master on 4.4.0-81 kernel,
> there is a warning:
>
>     CC [M]  /root/ovs/datapath/linux/datapath.o
>     /root/ovs/datapath/linux/datapath.c: In function
>     ‘ovs_flow_cmd_set’:
>     /root/ovs/datapath/linux/datapath.c:1221:1: warning:
>     the frame size of 1040 bytes is larger than 1024 bytes
>     [-Wframe-larger-than=]
>
> This patch use kmalloc to malloc mem for sw_flow_mask and
> avoid using stack.
>
> Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
> ---
>  net/openvswitch/datapath.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
> index c85029c..da8cd68 100644
> --- a/net/openvswitch/datapath.c
> +++ b/net/openvswitch/datapath.c
> @@ -1107,7 +1107,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
>         struct ovs_header *ovs_header = info->userhdr;
>         struct sw_flow_key key;
>         struct sw_flow *flow;
> -       struct sw_flow_mask mask;
> +       struct sw_flow_mask *mask;
>         struct sk_buff *reply = NULL;
>         struct datapath *dp;
>         struct sw_flow_actions *old_acts = NULL, *acts = NULL;
> @@ -1120,7 +1120,11 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
>
>         ufid_present = ovs_nla_get_ufid(&sfid, a[OVS_FLOW_ATTR_UFID], log);
>         if (a[OVS_FLOW_ATTR_KEY]) {
> -               ovs_match_init(&match, &key, true, &mask);
> +               mask = kmalloc(sizeof(struct sw_flow_mask), GFP_KERNEL);
> +               if (!mask)
> +                       return -ENOMEM;
> +
> +               ovs_match_init(&match, &key, true, mask);

Rather than allocating mask object and freeing it at the end, can you
factor out code which needs mask into new function to save some stack
space in this function?

>                 error = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY],
>                                           a[OVS_FLOW_ATTR_MASK], log);
>         } else if (!ufid_present) {
> @@ -1141,7 +1145,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
>                 }
>
>                 acts = get_flow_actions(net, a[OVS_FLOW_ATTR_ACTIONS], &key,
> -                                       &mask, log);
> +                                       mask, log);
>                 if (IS_ERR(acts)) {
>                         error = PTR_ERR(acts);
>                         goto error;
> @@ -1216,6 +1220,7 @@ err_unlock_ovs:
>  err_kfree_acts:
>         ovs_nla_free_flow_actions(acts);
>  error:
> +       kfree(mask);

mask free is missing in usual, no error case.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] datapath: Avoid using stack larger than 1024.
  2017-06-27  7:03 Tonghao Zhang
@ 2017-06-27 16:38 ` Greg Rose
  0 siblings, 0 replies; 4+ messages in thread
From: Greg Rose @ 2017-06-27 16:38 UTC (permalink / raw)
  To: Tonghao Zhang; +Cc: netdev, pravin shelar

On 06/27/2017 12:03 AM, Tonghao Zhang wrote:
> When compiling OvS-master on 4.4.0-81 kernel,
> there is a warning:
>
>      CC [M]  /root/ovs/datapath/linux/datapath.o
>      /root/ovs/datapath/linux/datapath.c: In function
>      ‘ovs_flow_cmd_set’:
>      /root/ovs/datapath/linux/datapath.c:1221:1: warning:
>      the frame size of 1040 bytes is larger than 1024 bytes
>      [-Wframe-larger-than=]
>
> This patch use kmalloc to malloc mem for sw_flow_mask and
> avoid using stack.
>
> Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
> ---
>   datapath/datapath.c | 11 ++++++++---
>   1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/datapath/datapath.c b/datapath/datapath.c
> index c85029c..da8cd68 100644
> --- a/datapath/datapath.c
> +++ b/datapath/datapath.c
> @@ -1107,7 +1107,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
>       struct ovs_header *ovs_header = info->userhdr;
>       struct sw_flow_key key;
>       struct sw_flow *flow;
> -    struct sw_flow_mask mask;
> +    struct sw_flow_mask *mask;
>       struct sk_buff *reply = NULL;
>       struct datapath *dp;
>       struct sw_flow_actions *old_acts = NULL, *acts = NULL;
> @@ -1120,7 +1120,11 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
>
>       ufid_present = ovs_nla_get_ufid(&sfid, a[OVS_FLOW_ATTR_UFID], log);
>       if (a[OVS_FLOW_ATTR_KEY]) {
> -        ovs_match_init(&match, &key, true, &mask);
> +        mask = kmalloc(sizeof(struct sw_flow_mask), GFP_KERNEL);
> +        if (!mask)
> +            return -ENOMEM;
> +
> +        ovs_match_init(&match, &key, true, mask);
>           error = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY],
>                         a[OVS_FLOW_ATTR_MASK], log);
>       } else if (!ufid_present) {
> @@ -1141,7 +1145,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
>           }
>
>           acts = get_flow_actions(net, a[OVS_FLOW_ATTR_ACTIONS], &key,
> -                    &mask, log);
> +                    mask, log);
>           if (IS_ERR(acts)) {
>               error = PTR_ERR(acts);
>               goto error;
> @@ -1216,6 +1220,7 @@ err_unlock_ovs:
>   err_kfree_acts:
>       ovs_nla_free_flow_actions(acts);
>   error:
> +    kfree(mask);
>       return error;
>   }
>
>
It looks fine to me but let's copy the maintainer Pravin

- Greg

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH] datapath: Avoid using stack larger than 1024.
@ 2017-06-27  7:03 Tonghao Zhang
  2017-06-27 16:38 ` Greg Rose
  0 siblings, 1 reply; 4+ messages in thread
From: Tonghao Zhang @ 2017-06-27  7:03 UTC (permalink / raw)
  To: netdev; +Cc: Tonghao Zhang

When compiling OvS-master on 4.4.0-81 kernel,
there is a warning:

    CC [M]  /root/ovs/datapath/linux/datapath.o
    /root/ovs/datapath/linux/datapath.c: In function
    ‘ovs_flow_cmd_set’:
    /root/ovs/datapath/linux/datapath.c:1221:1: warning:
    the frame size of 1040 bytes is larger than 1024 bytes
    [-Wframe-larger-than=]

This patch use kmalloc to malloc mem for sw_flow_mask and
avoid using stack.

Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
---
 datapath/datapath.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/datapath/datapath.c b/datapath/datapath.c
index c85029c..da8cd68 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1107,7 +1107,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 	struct ovs_header *ovs_header = info->userhdr;
 	struct sw_flow_key key;
 	struct sw_flow *flow;
-	struct sw_flow_mask mask;
+	struct sw_flow_mask *mask;
 	struct sk_buff *reply = NULL;
 	struct datapath *dp;
 	struct sw_flow_actions *old_acts = NULL, *acts = NULL;
@@ -1120,7 +1120,11 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 
 	ufid_present = ovs_nla_get_ufid(&sfid, a[OVS_FLOW_ATTR_UFID], log);
 	if (a[OVS_FLOW_ATTR_KEY]) {
-		ovs_match_init(&match, &key, true, &mask);
+		mask = kmalloc(sizeof(struct sw_flow_mask), GFP_KERNEL);
+		if (!mask)
+			return -ENOMEM;
+
+		ovs_match_init(&match, &key, true, mask);
 		error = ovs_nla_get_match(net, &match, a[OVS_FLOW_ATTR_KEY],
 					  a[OVS_FLOW_ATTR_MASK], log);
 	} else if (!ufid_present) {
@@ -1141,7 +1145,7 @@ static int ovs_flow_cmd_set(struct sk_buff *skb, struct genl_info *info)
 		}
 
 		acts = get_flow_actions(net, a[OVS_FLOW_ATTR_ACTIONS], &key,
-					&mask, log);
+					mask, log);
 		if (IS_ERR(acts)) {
 			error = PTR_ERR(acts);
 			goto error;
@@ -1216,6 +1220,7 @@ err_unlock_ovs:
 err_kfree_acts:
 	ovs_nla_free_flow_actions(acts);
 error:
+	kfree(mask);
 	return error;
 }
 
-- 
1.8.3.1

^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2017-06-27 21:19 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-06-27  9:20 [PATCH] datapath: Avoid using stack larger than 1024 Tonghao Zhang
2017-06-27 21:19 ` Pravin Shelar
  -- strict thread matches above, loose matches on Subject: below --
2017-06-27  7:03 Tonghao Zhang
2017-06-27 16:38 ` Greg Rose

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