* [PATCH] netpoll: fix netpoll_send_udp() bugs
@ 2012-06-13 5:30 Eric Dumazet
2012-06-13 11:18 ` Neil Horman
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Eric Dumazet @ 2012-06-13 5:30 UTC (permalink / raw)
To: David Miller; +Cc: netdev, Bogdan Hamciuc, Herbert Xu, Neil Horman
From: Eric Dumazet <edumazet@google.com>
Bogdan Hamciuc diagnosed and fixed following bug in netpoll_send_udp() :
"skb->len += len;" instead of "skb_put(skb, len);"
Meaning that _if_ a network driver needs to call skb_realloc_headroom(),
only packet headers would be copied, leaving garbage in the payload.
However the skb_realloc_headroom() must be avoided as much as possible
since it requires memory and netpoll tries hard to work even if memory
is exhausted (using a pool of preallocated skbs)
It appears netpoll_send_udp() reserved 16 bytes for the ethernet header,
which happens to work for typicall drivers but not all.
Right thing is to use LL_RESERVED_SPACE(dev)
(And also add dev->needed_tailroom of tailroom)
This patch combines both fixes.
Many thanks to Bogdan for raising this issue.
Reported-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Neil Horman <nhorman@tuxdriver.com>
---
net/core/netpoll.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 3d84fb9..f9f40b9 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -362,22 +362,23 @@ EXPORT_SYMBOL(netpoll_send_skb_on_dev);
void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
{
- int total_len, eth_len, ip_len, udp_len;
+ int total_len, ip_len, udp_len;
struct sk_buff *skb;
struct udphdr *udph;
struct iphdr *iph;
struct ethhdr *eth;
udp_len = len + sizeof(*udph);
- ip_len = eth_len = udp_len + sizeof(*iph);
- total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
+ ip_len = udp_len + sizeof(*iph);
+ total_len = ip_len + LL_RESERVED_SPACE(np->dev);
- skb = find_skb(np, total_len, total_len - len);
+ skb = find_skb(np, total_len + np->dev->needed_tailroom,
+ total_len - len);
if (!skb)
return;
skb_copy_to_linear_data(skb, msg, len);
- skb->len += len;
+ skb_put(skb, len);
skb_push(skb, sizeof(*udph));
skb_reset_transport_header(skb);
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] netpoll: fix netpoll_send_udp() bugs
2012-06-13 5:30 [PATCH] netpoll: fix netpoll_send_udp() bugs Eric Dumazet
@ 2012-06-13 11:18 ` Neil Horman
2012-06-13 13:59 ` Cong Wang
2012-06-13 22:58 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: Neil Horman @ 2012-06-13 11:18 UTC (permalink / raw)
To: Eric Dumazet; +Cc: David Miller, netdev, Bogdan Hamciuc, Herbert Xu
On Wed, Jun 13, 2012 at 07:30:21AM +0200, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> Bogdan Hamciuc diagnosed and fixed following bug in netpoll_send_udp() :
>
> "skb->len += len;" instead of "skb_put(skb, len);"
>
> Meaning that _if_ a network driver needs to call skb_realloc_headroom(),
> only packet headers would be copied, leaving garbage in the payload.
>
> However the skb_realloc_headroom() must be avoided as much as possible
> since it requires memory and netpoll tries hard to work even if memory
> is exhausted (using a pool of preallocated skbs)
>
> It appears netpoll_send_udp() reserved 16 bytes for the ethernet header,
> which happens to work for typicall drivers but not all.
>
> Right thing is to use LL_RESERVED_SPACE(dev)
> (And also add dev->needed_tailroom of tailroom)
>
> This patch combines both fixes.
>
> Many thanks to Bogdan for raising this issue.
>
> Reported-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Tested-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Neil Horman <nhorman@tuxdriver.com>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] netpoll: fix netpoll_send_udp() bugs
2012-06-13 5:30 [PATCH] netpoll: fix netpoll_send_udp() bugs Eric Dumazet
2012-06-13 11:18 ` Neil Horman
@ 2012-06-13 13:59 ` Cong Wang
2012-06-13 22:58 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: Cong Wang @ 2012-06-13 13:59 UTC (permalink / raw)
To: netdev
On Wed, 13 Jun 2012 at 05:30 GMT, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> Bogdan Hamciuc diagnosed and fixed following bug in netpoll_send_udp() :
>
> "skb->len += len;" instead of "skb_put(skb, len);"
>
> Meaning that _if_ a network driver needs to call skb_realloc_headroom(),
> only packet headers would be copied, leaving garbage in the payload.
>
> However the skb_realloc_headroom() must be avoided as much as possible
> since it requires memory and netpoll tries hard to work even if memory
> is exhausted (using a pool of preallocated skbs)
>
> It appears netpoll_send_udp() reserved 16 bytes for the ethernet header,
> which happens to work for typicall drivers but not all.
>
> Right thing is to use LL_RESERVED_SPACE(dev)
> (And also add dev->needed_tailroom of tailroom)
>
> This patch combines both fixes.
>
> Many thanks to Bogdan for raising this issue.
>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Need to apply to -stable?
Thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] netpoll: fix netpoll_send_udp() bugs
2012-06-13 5:30 [PATCH] netpoll: fix netpoll_send_udp() bugs Eric Dumazet
2012-06-13 11:18 ` Neil Horman
2012-06-13 13:59 ` Cong Wang
@ 2012-06-13 22:58 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2012-06-13 22:58 UTC (permalink / raw)
To: eric.dumazet; +Cc: netdev, bogdan.hamciuc, herbert, nhorman
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 13 Jun 2012 07:30:21 +0200
> From: Eric Dumazet <edumazet@google.com>
>
> Bogdan Hamciuc diagnosed and fixed following bug in netpoll_send_udp() :
>
> "skb->len += len;" instead of "skb_put(skb, len);"
>
> Meaning that _if_ a network driver needs to call skb_realloc_headroom(),
> only packet headers would be copied, leaving garbage in the payload.
>
> However the skb_realloc_headroom() must be avoided as much as possible
> since it requires memory and netpoll tries hard to work even if memory
> is exhausted (using a pool of preallocated skbs)
>
> It appears netpoll_send_udp() reserved 16 bytes for the ethernet header,
> which happens to work for typicall drivers but not all.
>
> Right thing is to use LL_RESERVED_SPACE(dev)
> (And also add dev->needed_tailroom of tailroom)
>
> This patch combines both fixes.
>
> Many thanks to Bogdan for raising this issue.
>
> Reported-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Tested-by: Bogdan Hamciuc <bogdan.hamciuc@freescale.com>
Applied and queued up for -stable, thanks Eric.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-06-13 22:58 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2012-06-13 5:30 [PATCH] netpoll: fix netpoll_send_udp() bugs Eric Dumazet
2012-06-13 11:18 ` Neil Horman
2012-06-13 13:59 ` Cong Wang
2012-06-13 22:58 ` David Miller
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