From: Andrew Vagin <[email protected]>
Currently if a socket was repaired with a few packet in a write queue,
a kernel bug may be triggered:
kernel BUG at net/ipv4/tcp_output.c:2330!
RIP: 0010:[<ffffffff8155784f>] tcp_retransmit_skb+0x5ff/0x610
According to the initial realization v3.4-rc2-963-gc0e88ff,
all skb-s should look like already posted. This patch fixes code
according with this sentence.
Here are three points, which were not done in the initial patch:
1. A tcp send head should not be changed
2. Initialize TSO state of a skb
3. Reset the retransmission time
This patch moves logic from tcp_sendmsg to tcp_write_xmit. A packet
passes the ussual way, but isn't sent to network. This patch solves
all described problems and handles tcp_sendpages.
Cc: Pavel Emelyanov <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Alexey Kuznetsov <[email protected]>
Cc: James Morris <[email protected]>
Cc: Hideaki YOSHIFUJI <[email protected]>
Cc: Patrick McHardy <[email protected]>
Signed-off-by: Andrey Vagin <[email protected]>
---
net/ipv4/tcp.c | 4 ++--
net/ipv4/tcp_output.c | 4 ++++
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 197c000..083092e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1212,7 +1212,7 @@ new_segment:
wait_for_sndbuf:
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
- if (copied && likely(!tp->repair))
+ if (copied)
tcp_push(sk, flags & ~MSG_MORE, mss_now, TCP_NAGLE_PUSH);
if ((err = sk_stream_wait_memory(sk, &timeo)) != 0)
@@ -1223,7 +1223,7 @@ wait_for_memory:
}
out:
- if (copied && likely(!tp->repair))
+ if (copied)
tcp_push(sk, flags, mss_now, tp->nonagle);
release_sock(sk);
return copied + copied_syn;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index cfe6ffe..2798706 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1986,6 +1986,9 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
tso_segs = tcp_init_tso_segs(sk, skb, mss_now);
BUG_ON(!tso_segs);
+ if (unlikely(tp->repair) && tp->repair_queue == TCP_SEND_QUEUE)
+ goto repair; /* Skip network transmission */
+
cwnd_quota = tcp_cwnd_test(tp, skb);
if (!cwnd_quota)
break;
@@ -2026,6 +2029,7 @@ static bool tcp_write_xmit(struct sock *sk, unsigned int mss_now, int nonagle,
if (unlikely(tcp_transmit_skb(sk, skb, 1, gfp)))
break;
+repair:
/* Advance the send_head. This one is sent out.
* This call will increment packets_out.
*/
--
1.7.11.7
On 11/15/2012 06:03 PM, Andrey Vagin wrote:
> From: Andrew Vagin <[email protected]>
>
> Currently if a socket was repaired with a few packet in a write queue,
> a kernel bug may be triggered:
>
> kernel BUG at net/ipv4/tcp_output.c:2330!
> RIP: 0010:[<ffffffff8155784f>] tcp_retransmit_skb+0x5ff/0x610
>
> According to the initial realization v3.4-rc2-963-gc0e88ff,
> all skb-s should look like already posted. This patch fixes code
> according with this sentence.
>
> Here are three points, which were not done in the initial patch:
> 1. A tcp send head should not be changed
> 2. Initialize TSO state of a skb
> 3. Reset the retransmission time
>
> This patch moves logic from tcp_sendmsg to tcp_write_xmit. A packet
> passes the ussual way, but isn't sent to network. This patch solves
> all described problems and handles tcp_sendpages.
>
> Cc: Pavel Emelyanov <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Alexey Kuznetsov <[email protected]>
> Cc: James Morris <[email protected]>
> Cc: Hideaki YOSHIFUJI <[email protected]>
> Cc: Patrick McHardy <[email protected]>
> Signed-off-by: Andrey Vagin <[email protected]>
Acked-by: Pavel Emelyanov <[email protected]>
On Thu, 2012-11-15 at 18:03 +0400, Andrey Vagin wrote:
> From: Andrew Vagin <[email protected]>
>
> Currently if a socket was repaired with a few packet in a write queue,
> a kernel bug may be triggered:
>
> kernel BUG at net/ipv4/tcp_output.c:2330!
> RIP: 0010:[<ffffffff8155784f>] tcp_retransmit_skb+0x5ff/0x610
>
> According to the initial realization v3.4-rc2-963-gc0e88ff,
> all skb-s should look like already posted. This patch fixes code
> according with this sentence.
>
> Here are three points, which were not done in the initial patch:
> 1. A tcp send head should not be changed
> 2. Initialize TSO state of a skb
> 3. Reset the retransmission time
>
> This patch moves logic from tcp_sendmsg to tcp_write_xmit. A packet
> passes the ussual way, but isn't sent to network. This patch solves
> all described problems and handles tcp_sendpages.
>
> Cc: Pavel Emelyanov <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: Alexey Kuznetsov <[email protected]>
> Cc: James Morris <[email protected]>
> Cc: Hideaki YOSHIFUJI <[email protected]>
> Cc: Patrick McHardy <[email protected]>
> Signed-off-by: Andrey Vagin <[email protected]>
Any chance these tcp repair hacks could be done outside of tcp fast
path ?
From: Pavel Emelyanov <[email protected]>
Date: Thu, 15 Nov 2012 18:10:59 +0400
> On 11/15/2012 06:03 PM, Andrey Vagin wrote:
>> From: Andrew Vagin <[email protected]>
>>
>> Currently if a socket was repaired with a few packet in a write queue,
>> a kernel bug may be triggered:
>>
>> kernel BUG at net/ipv4/tcp_output.c:2330!
>> RIP: 0010:[<ffffffff8155784f>] tcp_retransmit_skb+0x5ff/0x610
>>
>> According to the initial realization v3.4-rc2-963-gc0e88ff,
>> all skb-s should look like already posted. This patch fixes code
>> according with this sentence.
>>
>> Here are three points, which were not done in the initial patch:
>> 1. A tcp send head should not be changed
>> 2. Initialize TSO state of a skb
>> 3. Reset the retransmission time
>>
>> This patch moves logic from tcp_sendmsg to tcp_write_xmit. A packet
>> passes the ussual way, but isn't sent to network. This patch solves
>> all described problems and handles tcp_sendpages.
...
>> Signed-off-by: Andrey Vagin <[email protected]>
>
> Acked-by: Pavel Emelyanov <[email protected]>
Applied and queued up for -stable, thanks.