[PATCH 1/1 -next] 6LoWPAN: fix skb_copy call

[PATCH 1/1 -next] 6LoWPAN: fix skb_copy call

[Alexander Smirnov]

This patch fixes 2 issues in lowpan_skb_deliver function:
1. Check for return status of skb_copy call;
2. Use skb_copy with proper GFP flag depending on context.

Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 net/ieee802154/6lowpan.c |   18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index cf304cc..cac1361 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -477,9 +477,15 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
 	struct sk_buff *new;
 	struct lowpan_dev_record *entry;
 	int stat = NET_RX_SUCCESS;
+	gfp_t mask;
 
-	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
-								GFP_KERNEL);
+	if (in_interrupt())
+		mask = GFP_ATOMIC;
+	else
+		mask = GFP_KERNEL;
+
+	new = skb_copy_expand(skb, sizeof(struct ipv6hdr),
+					skb_tailroom(skb), mask);
 	kfree_skb(skb);
 
 	if (NULL == new)
@@ -495,7 +501,13 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &lowpan_devices, list)
 		if (lowpan_dev_info(entry->ldev)->real_dev == new->dev) {
-			skb = skb_copy(new, GFP_KERNEL);
+			skb = skb_copy(new, mask);
+
+			if (NULL == skb) {
+				kfree_skb(new);
+				return -ENOMEM;
+			}
+
 			skb->dev = entry->ldev;
 
 			if (in_interrupt())
-- 
1.7.2.5


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Re: [PATCH 1/1 -next] 6LoWPAN: fix skb_copy call

[Eric Dumazet]

Le jeudi 01 septembre 2011 à 16:21 +0400, Alexander Smirnov a écrit :
> This patch fixes 2 issues in lowpan_skb_deliver function:
> 1. Check for return status of skb_copy call;
> 2. Use skb_copy with proper GFP flag depending on context.
> 

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>

patch adds a new bug, see below

> Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
> ---
>  net/ieee802154/6lowpan.c |   18 +++++++++++++++---
>  1 files changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
> index cf304cc..cac1361 100644
> --- a/net/ieee802154/6lowpan.c
> +++ b/net/ieee802154/6lowpan.c
> @@ -477,9 +477,15 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
>  	struct sk_buff *new;
>  	struct lowpan_dev_record *entry;
>  	int stat = NET_RX_SUCCESS;
> +	gfp_t mask;
>  
> -	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
> -								GFP_KERNEL);
> +	if (in_interrupt())
> +		mask = GFP_ATOMIC;
> +	else
> +		mask = GFP_KERNEL;
> +
> +	new = skb_copy_expand(skb, sizeof(struct ipv6hdr),
> +					skb_tailroom(skb), mask);
>  	kfree_skb(skb);
>  
>  	if (NULL == new)
> @@ -495,7 +501,13 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
>  	rcu_read_lock();
>  	list_for_each_entry_rcu(entry, &lowpan_devices, list)
>  		if (lowpan_dev_info(entry->ldev)->real_dev == new->dev) {
> -			skb = skb_copy(new, GFP_KERNEL);
> +			skb = skb_copy(new, mask);
> +
> +			if (NULL == skb) {
> +				kfree_skb(new);

rcu_read_unlock() missing.

	just do : 
			stat = -ENOMEM;
			break; (to exit from list_for_each_entry_rcu()) 

> +				return -ENOMEM;
> +			}
> +
>  			skb->dev = entry->ldev;
>  
>  			if (in_interrupt())

[PATCH v2 -next] 6LoWPAN: fix skb_copy call

[Alexander Smirnov]

This patch fixes 2 issues in lowpan_skb_deliver function:
1. Check for return status of skb_copy call;
2. Use skb_copy with proper GFP flag depending on context.

Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 net/ieee802154/6lowpan.c |   18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index cf304cc..16100be 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -477,9 +477,15 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
 	struct sk_buff *new;
 	struct lowpan_dev_record *entry;
 	int stat = NET_RX_SUCCESS;
+	gfp_t mask;
 
-	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
-								GFP_KERNEL);
+	if (in_interrupt())
+		mask = GFP_ATOMIC;
+	else
+		mask = GFP_KERNEL;
+
+	new = skb_copy_expand(skb, sizeof(struct ipv6hdr),
+					skb_tailroom(skb), mask);
 	kfree_skb(skb);
 
 	if (NULL == new)
@@ -495,7 +501,13 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &lowpan_devices, list)
 		if (lowpan_dev_info(entry->ldev)->real_dev == new->dev) {
-			skb = skb_copy(new, GFP_KERNEL);
+			skb = skb_copy(new, mask);
+
+			if (NULL == skb) {
+				stat = -ENOMEM;
+				break;
+			}
+
 			skb->dev = entry->ldev;
 
 			if (in_interrupt())
-- 
1.7.2.5


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Re: [PATCH v2 -next] 6LoWPAN: fix skb_copy call

[Eric Dumazet]

Le jeudi 01 septembre 2011 à 16:54 +0400, Alexander Smirnov a écrit :
> This patch fixes 2 issues in lowpan_skb_deliver function:
> 1. Check for return status of skb_copy call;
> 2. Use skb_copy with proper GFP flag depending on context.
> 
> Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
> ---
>  net/ieee802154/6lowpan.c |   18 +++++++++++++++---
>  1 files changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
> index cf304cc..16100be 100644
> --- a/net/ieee802154/6lowpan.c
> +++ b/net/ieee802154/6lowpan.c
> @@ -477,9 +477,15 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
>  	struct sk_buff *new;
>  	struct lowpan_dev_record *entry;
>  	int stat = NET_RX_SUCCESS;
> +	gfp_t mask;
>  
> -	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
> -								GFP_KERNEL);
> +	if (in_interrupt())
> +		mask = GFP_ATOMIC;
> +	else
> +		mask = GFP_KERNEL;

I am not sure to understand if lowpan_skb_deliver() can be called in
pure process context. I feel we are in softirq handler or we have
disabled BH, so GFP_ATOMIC is the only choice.

If you are unsure, you could use following helper :

	mask = gfp_any();

> +
> +	new = skb_copy_expand(skb, sizeof(struct ipv6hdr),
> +					skb_tailroom(skb), mask);
>  	kfree_skb(skb);
>  

Re: [PATCH v2 -next] 6LoWPAN: fix skb_copy call

[Alexander Smirnov]

Hi Eric,

hmm, I think you are right.

First 6LoWPAN implementation was developed as a part of MAC layer and
code was based on this layer approach. But now 6lowpan is
MAC-independent, it's just a netif_rx hook and looks like I missed
this moment during migration.

sorry for confusion.

With best regards,
Alexander

2011/9/1 Eric Dumazet <eric.dumazet@gmail.com>:
> Le jeudi 01 septembre 2011 à 16:54 +0400, Alexander Smirnov a écrit :
>> This patch fixes 2 issues in lowpan_skb_deliver function:
>> 1. Check for return status of skb_copy call;
>> 2. Use skb_copy with proper GFP flag depending on context.
>>
>> Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
>> ---
>>  net/ieee802154/6lowpan.c |   18 +++++++++++++++---
>>  1 files changed, 15 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
>> index cf304cc..16100be 100644
>> --- a/net/ieee802154/6lowpan.c
>> +++ b/net/ieee802154/6lowpan.c
>> @@ -477,9 +477,15 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
>>       struct sk_buff *new;
>>       struct lowpan_dev_record *entry;
>>       int stat = NET_RX_SUCCESS;
>> +     gfp_t mask;
>>
>> -     new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
>> -                                                             GFP_KERNEL);
>> +     if (in_interrupt())
>> +             mask = GFP_ATOMIC;
>> +     else
>> +             mask = GFP_KERNEL;
>
> I am not sure to understand if lowpan_skb_deliver() can be called in
> pure process context. I feel we are in softirq handler or we have
> disabled BH, so GFP_ATOMIC is the only choice.
>
> If you are unsure, you could use following helper :
>
>        mask = gfp_any();
>
>> +
>> +     new = skb_copy_expand(skb, sizeof(struct ipv6hdr),
>> +                                     skb_tailroom(skb), mask);
>>       kfree_skb(skb);
>>
>
>

Re: [PATCH v2 -next] 6LoWPAN: fix skb_copy call

[Daniel Baluta]

> +                       if (NULL == skb) {
> +                               stat = -ENOMEM;
> +                               break;
> +                       }

This can hurt our eyes :). I think the common convention
is to use: "if (skb == NULL) " or simply "if (!skb) "

thanks,
Daniel.

Re: [PATCH v2 -next] 6LoWPAN: fix skb_copy call

[David Miller]

From: Alexander Smirnov <alex.bluesman.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Date: Thu,  1 Sep 2011 16:54:13 +0400

> This patch fixes 2 issues in lowpan_skb_deliver function:
> 1. Check for return status of skb_copy call;
> 2. Use skb_copy with proper GFP flag depending on context.
> 
> Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Applied.

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virtual desktop model.http://www.accelacomm.com/jaw/sfnl/114/51426474/

[PATCH v3 -next] 6LoWPAN: fix skb_copy call

[Alexander Smirnov]

This patch fixes 2 issues in lowpan_skb_deliver function:
1. Check for return status of skb_copy call;
2. Use skb_copy with proper GFP flag, drop check for non-interrupt
context.

Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 net/ieee802154/6lowpan.c |   17 +++++++++--------
 1 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index cf304cc..deb2adf 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -479,10 +479,10 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
 	int stat = NET_RX_SUCCESS;
 
 	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
-								GFP_KERNEL);
+								GFP_ATOMIC);
 	kfree_skb(skb);
 
-	if (NULL == new)
+	if (!new)
 		return -ENOMEM;
 
 	skb_push(new, sizeof(struct ipv6hdr));
@@ -495,13 +495,14 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
 	rcu_read_lock();
 	list_for_each_entry_rcu(entry, &lowpan_devices, list)
 		if (lowpan_dev_info(entry->ldev)->real_dev == new->dev) {
-			skb = skb_copy(new, GFP_KERNEL);
-			skb->dev = entry->ldev;
+			skb = skb_copy(new, GFP_ATOMIC);
+			if (!skb) {
+				stat = -ENOMEM;
+				break;
+			}
 
-			if (in_interrupt())
-				stat = netif_rx(skb);
-			else
-				stat = netif_rx_ni(skb);
+			skb->dev = entry->ldev;
+			stat = netif_rx(skb);
 		}
 	rcu_read_unlock();
 
-- 
1.7.2.5


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price-free! And you'll get a free "Love Thy Logs" t-shirt when you
download Logger. Secure your free ArcSight Logger TODAY!
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Re: [PATCH v3 -next] 6LoWPAN: fix skb_copy call

[Eric Dumazet]

Le jeudi 01 septembre 2011 à 17:55 +0400, Alexander Smirnov a écrit :
> This patch fixes 2 issues in lowpan_skb_deliver function:
> 1. Check for return status of skb_copy call;
> 2. Use skb_copy with proper GFP flag, drop check for non-interrupt
> context.
> 
> Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

> ---
>  net/ieee802154/6lowpan.c |   17 +++++++++--------
>  1 files changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
> index cf304cc..deb2adf 100644
> --- a/net/ieee802154/6lowpan.c
> +++ b/net/ieee802154/6lowpan.c
> @@ -479,10 +479,10 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
>  	int stat = NET_RX_SUCCESS;
>  
>  	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
> -								GFP_KERNEL);
> +								GFP_ATOMIC);
>  	kfree_skb(skb);
>  
> -	if (NULL == new)
> +	if (!new)
>  		return -ENOMEM;
>  
>  	skb_push(new, sizeof(struct ipv6hdr));
> @@ -495,13 +495,14 @@ static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
>  	rcu_read_lock();
>  	list_for_each_entry_rcu(entry, &lowpan_devices, list)
>  		if (lowpan_dev_info(entry->ldev)->real_dev == new->dev) {
> -			skb = skb_copy(new, GFP_KERNEL);
> -			skb->dev = entry->ldev;
> +			skb = skb_copy(new, GFP_ATOMIC);
> +			if (!skb) {
> +				stat = -ENOMEM;
> +				break;
> +			}
>  
> -			if (in_interrupt())
> -				stat = netif_rx(skb);
> -			else
> -				stat = netif_rx_ni(skb);
> +			skb->dev = entry->ldev;
> +			stat = netif_rx(skb);
>  		}
>  	rcu_read_unlock();
>  

Re: [PATCH v3 -next] 6LoWPAN: fix skb_copy call

[David Miller]

From: Alexander Smirnov <alex.bluesman.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Date: Thu,  1 Sep 2011 17:55:15 +0400

> This patch fixes 2 issues in lowpan_skb_deliver function:
> 1. Check for return status of skb_copy call;
> 2. Use skb_copy with proper GFP flag, drop check for non-interrupt
> context.
> 
> Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Just to make it clear, I applied -v3 of this patch not -v2. :-)


------------------------------------------------------------------------------
Doing More with Less: The Next Generation Virtual Desktop 
What are the key obstacles that have prevented many mid-market businesses
from deploying virtual desktops?   How do next-generation virtual desktops
provide companies an easier-to-deploy, easier-to-manage and more affordable
virtual desktop model.http://www.accelacomm.com/jaw/sfnl/114/51426474/