Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <852cef0c-2c1a-fdcd-4ee9-4a0bca3f54c5@gmail.com>
Date:   Thu, 3 Aug 2023 14:47:35 +0300
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.13.0
Subject: Re: [PATCH net-next v10 08/16] tls: Inline do_tcp_sendpages()
To:     Jakub Kicinski <kuba@kernel.org>
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>
References: <ecbb5d7e-7238-28e2-1a17-686325e2bb50@gmail.com>
 <4c49176f-147a-4283-f1b1-32aac7b4b996@gmail.com>
 <20230522121125.2595254-1-dhowells@redhat.com>
 <20230522121125.2595254-9-dhowells@redhat.com>
 <2267272.1686150217@warthog.procyon.org.uk>
 <5a9d4ffb-a569-3f60-6ac8-070ab5e5f5ad@gmail.com>
 <776549.1687167344@warthog.procyon.org.uk>
 <7337a904-231d-201d-397a-7bbe7cae929f@gmail.com>
 <20230630102143.7deffc30@kernel.org>
 <f0538006-6641-eaf6-b7b5-b3ef57afc652@gmail.com>
 <20230705091914.5bee12f8@kernel.org>
 <bbdce803-0f23-7d3f-f75a-2bc3cfb794af@gmail.com>
 <20230725173036.442ba8ba@kernel.org>
Content-Language: en-US
From:   Tariq Toukan <ttoukan.linux@gmail.com>
In-Reply-To: <20230725173036.442ba8ba@kernel.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 26/07/2023 3:30, Jakub Kicinski wrote:
> 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);

Hi Jakub,

When applying this patch, repro disappears! :)
Apparently it is related to the warning.
Please go on and submit it.

Tested-by: Tariq Toukan <tariqt@nvidia.com>

We are going to run more comprehensive tests, I'll let you know if we 
find anything unusual.

Regards,
Tariq