[PATCH net-next v2] selftests: return failure when timestamps can't be reported

[PATCH net-next v2] selftests: return failure when timestamps can't be reported

[Jason Xing]

From: Jason Xing <kernelxing@tencent.com>

When I was trying to modify the tx timestamping feature, I found that
running "./txtimestamp -4 -C -L 127.0.0.1" didn't reflect the error:
I succeeded to generate timestamp stored in the skb but later failed
to report it to the userspace (which means failed to put css into cmsg).
It can happen when someone writes buggy codes in __sock_recv_timestamp(),
for example.

After adding the check so that running ./txtimestamp will reflect the
result correctly like this if there is a bug in the reporting phase:
protocol:     TCP
payload:      10
server port:  9000

family:       INET
test SND
    USR: 1725458477 s 667997 us (seq=0, len=0)
Failed to report timestamps
    USR: 1725458477 s 718128 us (seq=0, len=0)
Failed to report timestamps
    USR: 1725458477 s 768273 us (seq=0, len=0)
Failed to report timestamps
    USR: 1725458477 s 818416 us (seq=0, len=0)
Failed to report timestamps
...

In the future, it will help us detect whether the new coming patch has
bugs or not.

Signed-off-by: Jason Xing <kernelxing@tencent.com>
---
v2
Link: https://lore.kernel.org/all/20240904144446.41274-1-kerneljasonxing@gmail.com/
1. mainly change from "parse" to "report", update the commit message.
---
 tools/testing/selftests/net/txtimestamp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/txtimestamp.c b/tools/testing/selftests/net/txtimestamp.c
index ec60a16c9307..d626f22f9550 100644
--- a/tools/testing/selftests/net/txtimestamp.c
+++ b/tools/testing/selftests/net/txtimestamp.c
@@ -356,8 +356,12 @@ static void __recv_errmsg_cmsg(struct msghdr *msg, int payload_len)
 		}
 	}
 
-	if (batch > 1)
+	if (batch > 1) {
 		fprintf(stderr, "batched %d timestamps\n", batch);
+	} else if (!batch) {
+		fprintf(stderr, "Failed to report timestamps\n");
+		test_failed = true;
+	}
 }
 
 static int recv_errmsg(int fd)
-- 
2.37.3

Re: [PATCH net-next v2] selftests: return failure when timestamps can't be reported

[Jakub Kicinski]

On Fri,  6 Sep 2024 00:00:35 +0800 Jason Xing wrote:
> When I was trying to modify the tx timestamping feature, I found that
> running "./txtimestamp -4 -C -L 127.0.0.1" didn't reflect the error:
> I succeeded to generate timestamp stored in the skb but later failed
> to report it to the userspace (which means failed to put css into cmsg).
> It can happen when someone writes buggy codes in __sock_recv_timestamp(),
> for example.

Willem, thoughts?

Re: [PATCH net-next v2] selftests: return failure when timestamps can't be reported

[Willem de Bruijn]

Jakub Kicinski wrote:
> On Fri,  6 Sep 2024 00:00:35 +0800 Jason Xing wrote:
> > When I was trying to modify the tx timestamping feature, I found that
> > running "./txtimestamp -4 -C -L 127.0.0.1" didn't reflect the error:
> > I succeeded to generate timestamp stored in the skb but later failed
> > to report it to the userspace (which means failed to put css into cmsg).
> > It can happen when someone writes buggy codes in __sock_recv_timestamp(),
> > for example.
> 
> Willem, thoughts?

Reviewed-by: Willem de Bruijn <willemb@google.com>

Sorry, lost track of this.

Re: [PATCH net-next v2] selftests: return failure when timestamps can't be reported

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri,  6 Sep 2024 00:00:35 +0800 you wrote:
> From: Jason Xing <kernelxing@tencent.com>
> 
> When I was trying to modify the tx timestamping feature, I found that
> running "./txtimestamp -4 -C -L 127.0.0.1" didn't reflect the error:
> I succeeded to generate timestamp stored in the skb but later failed
> to report it to the userspace (which means failed to put css into cmsg).
> It can happen when someone writes buggy codes in __sock_recv_timestamp(),
> for example.
> 
> [...]

Here is the summary with links:
  - [net-next,v2] selftests: return failure when timestamps can't be reported
    https://git.kernel.org/netdev/net-next/c/a7e387375f22

You are awesome, thank you!
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