Re: [PATCH net-next v10 08/16] tls: Inline do_tcp_sendpages()

From: Jakub Kicinski <kuba@kernel.org>
To: Tariq Toukan <ttoukan.linux@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Paolo Abeni <pabeni@redhat.com>,
	Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	David Ahern <dsahern@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Christoph Hellwig <hch@infradead.org>,
	Jens Axboe <axboe@kernel.dk>, Jeff Layton <jlayton@kernel.org>,
	Christian Brauner <brauner@kernel.org>,
	Chuck Lever III <chuck.lever@oracle.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, Boris Pismenny <borisp@nvidia.com>,
	John Fastabend <john.fastabend@gmail.com>,
	Gal Pressman <gal@nvidia.com>,
	ranro@nvidia.com, samiram@nvidia.com, drort@nvidia.com,
	Tariq Toukan <tariqt@nvidia.com>
Subject: Re: [PATCH net-next v10 08/16] tls: Inline do_tcp_sendpages()
Date: Tue, 25 Jul 2023 17:30:36 -0700	[thread overview]
Message-ID: <20230725173036.442ba8ba@kernel.org> (raw)
In-Reply-To: <bbdce803-0f23-7d3f-f75a-2bc3cfb794af@gmail.com>

On Sun, 23 Jul 2023 09:35:56 +0300 Tariq Toukan wrote:
> Hi Jakub, David,
> 
> We repro the issue on the server side using this client command:
> $ wrk -b2.2.2.2 -t4 -c1000 -d5 --timeout 5s 
> https://2.2.2.3:20443/256000b.img
> 
> Port 20443 is configured with:
>      ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256;
>      sendfile    off;
> 
> 
> Important:
> 1. Couldn't repro with files smaller than 40KB.
> 2. Couldn't repro with "sendfile    on;"
> 
> In addition, we collected the vmcore (forced by panic_on_warn), it can 
> be downloaded from here:
> https://drive.google.com/file/d/1Fi2dzgq6k2hb2L_kwyntRjfLF6_RmbxB/view?usp=sharing

This has no symbols :(

There is a small bug in this commit, we should always set SPLICE.
But I don't see how that'd cause the warning you're seeing.
Does your build have CONFIG_DEBUG_VM enabled?

-->8-------------------------

From: Jakub Kicinski <kuba@kernel.org>
Date: Tue, 25 Jul 2023 17:03:25 -0700
Subject: net: tls: set MSG_SPLICE_PAGES consistently

We used to change the flags for the last segment, because
non-last segments had the MSG_SENDPAGE_NOTLAST flag set.
That flag is no longer a thing so remove the setting.

Since flags most likely don't have MSG_SPLICE_PAGES set
this avoids passing parts of the sg as splice and parts
as non-splice.

... tags ...
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 net/tls/tls_main.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index b6896126bb92..4a8ee2f6badb 100644
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -139,9 +139,6 @@ int tls_push_sg(struct sock *sk,
 
 	ctx->splicing_pages = true;
 	while (1) {
-		if (sg_is_last(sg))
-			msg.msg_flags = flags;
-
 		/* is sending application-limited? */
 		tcp_rate_check_app_limited(sk);
 		p = sg_page(sg);
-- 
2.41.0

