[PATCH v2] tcp: identify cryptic messages as TCP seq # bugs

[PATCH v2] tcp: identify cryptic messages as TCP seq # bugs

[Randy Dunlap]

From: Randy Dunlap <rdunlap@infradead.org>

Attempt to make cryptic TCP seq number error messages clearer by
(1) identifying the source of the message as "TCP", (2) identifying the
errors as "seq # bug", and (3) grouping the field identifiers and values
by separating them with commas.

E.g., the following message is changed from:

recvmsg bug 2: copied 73BCB6CD seq 70F17CBE rcvnxt 73BCB9AA fl 0
WARNING: CPU: 2 PID: 1501 at /linux/net/ipv4/tcp.c:1881 tcp_recvmsg+0x649/0xb90

to:

TCP recvmsg seq # bug 2: copied 73BCB6CD, seq 70F17CBE, rcvnxt 73BCB9AA, fl 0
WARNING: CPU: 2 PID: 1501 at /linux/net/ipv4/tcp.c:2011 tcp_recvmsg+0x694/0xba0

Suggested-by: 積丹尼 Dan Jacobson <jidanni@jidanni.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
---
v2: drop __func__ because it duplicates part of the error message.

 net/ipv4/tcp.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- linux-next-20180717.orig/net/ipv4/tcp.c
+++ linux-next-20180717/net/ipv4/tcp.c
@@ -1994,7 +1994,7 @@ int tcp_recvmsg(struct sock *sk, struct
 			 * shouldn't happen.
 			 */
 			if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
-				 "recvmsg bug: copied %X seq %X rcvnxt %X fl %X\n",
+				 "TCP recvmsg seq # bug: copied %X, seq %X, rcvnxt %X, fl %X\n",
 				 *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
 				 flags))
 				break;
@@ -2009,7 +2009,7 @@ int tcp_recvmsg(struct sock *sk, struct
 			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
 				goto found_fin_ok;
 			WARN(!(flags & MSG_PEEK),
-			     "recvmsg bug 2: copied %X seq %X rcvnxt %X fl %X\n",
+			     "TCP recvmsg seq # bug 2: copied %X, seq %X, rcvnxt %X, fl %X\n",
 			     *seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
 		}
 

Re: [PATCH v2] tcp: identify cryptic messages as TCP seq # bugs

[Eric Dumazet]

On 07/17/2018 06:27 PM, Randy Dunlap wrote:
> From: Randy Dunlap <rdunlap@infradead.org>
> 
> Attempt to make cryptic TCP seq number error messages clearer by
> (1) identifying the source of the message as "TCP", (2) identifying the
> errors as "seq # bug", and (3) grouping the field identifiers and values
> by separating them with commas.
> 
> E.g., the following message is changed from:
> 
> recvmsg bug 2: copied 73BCB6CD seq 70F17CBE rcvnxt 73BCB9AA fl 0
> WARNING: CPU: 2 PID: 1501 at /linux/net/ipv4/tcp.c:1881 tcp_recvmsg+0x649/0xb90
> 
> to:
> 
> TCP recvmsg seq # bug 2: copied 73BCB6CD, seq 70F17CBE, rcvnxt 73BCB9AA, fl 0
> WARNING: CPU: 2 PID: 1501 at /linux/net/ipv4/tcp.c:2011 tcp_recvmsg+0x694/0xba0
> 
> Suggested-by: 積丹尼 Dan Jacobson <jidanni@jidanni.org>
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>

Thanks Randy

Signed-off-by: Eric Dumazet <edumazet@google.com>

Re: [PATCH v2] tcp: identify cryptic messages as TCP seq # bugs

[David Miller]

From: Randy Dunlap <rdunlap@infradead.org>
Date: Tue, 17 Jul 2018 18:27:45 -0700

> From: Randy Dunlap <rdunlap@infradead.org>
> 
> Attempt to make cryptic TCP seq number error messages clearer by
> (1) identifying the source of the message as "TCP", (2) identifying the
> errors as "seq # bug", and (3) grouping the field identifiers and values
> by separating them with commas.
> 
> E.g., the following message is changed from:
> 
> recvmsg bug 2: copied 73BCB6CD seq 70F17CBE rcvnxt 73BCB9AA fl 0
> WARNING: CPU: 2 PID: 1501 at /linux/net/ipv4/tcp.c:1881 tcp_recvmsg+0x649/0xb90
> 
> to:
> 
> TCP recvmsg seq # bug 2: copied 73BCB6CD, seq 70F17CBE, rcvnxt 73BCB9AA, fl 0
> WARNING: CPU: 2 PID: 1501 at /linux/net/ipv4/tcp.c:2011 tcp_recvmsg+0x694/0xba0
> 
> Suggested-by: 積丹尼 Dan Jacobson <jidanni@jidanni.org>
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> ---
> v2: drop __func__ because it duplicates part of the error message.

Applied, thanks Randy.