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Message-ID: <5a9d4ffb-a569-3f60-6ac8-070ab5e5f5ad@gmail.com>
Date:   Tue, 13 Jun 2023 14:15:03 +0300
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Subject: Re: [PATCH net-next v10 08/16] tls: Inline do_tcp_sendpages()
To:     David Howells <dhowells@redhat.com>
Cc:     netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        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>
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 <20230522121125.2595254-1-dhowells@redhat.com>
 <20230522121125.2595254-9-dhowells@redhat.com>
 <2267272.1686150217@warthog.procyon.org.uk>
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From:   Tariq Toukan <ttoukan.linux@gmail.com>
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On 07/06/2023 18:03, David Howells wrote:
> Tariq Toukan <ttoukan.linux@gmail.com> wrote:
> 
>> My team spotted a new degradation in TLS TX device offload, bisected to this
>> patch.
> 
> I presume you're using some hardware (I'm guessing Mellanox?) that can
> actually do TLS offload?  Unfortunately, I don't have any hardware that can do
> this, so I can't test the tls_device stuff.
> 
>>  From a quick look at the patch, it's not clear to me what's going wrong.
>> Please let us know of any helpful information that we can provide to help in
>> the debug.
> 
> Can you find out what source line this corresponds to?
> 
> 	RIP: 0010:skb_splice_from_iter+0x102/0x300
> 
> Assuming you're building your own kernel, something like the following might
> do the trick:
> 
> 	echo "RIP: 0010:skb_splice_from_iter+0x102/0x300" |
> 	./scripts/decode_stacktrace.sh /my/built/vmlinux /my/build/tree
> 

Hi,

It's:
RIP: 0010:skb_splice_from_iter (/usr/linux/net/core/skbuff.c:6957)

which coresponds to this line:
                         if (WARN_ON_ONCE(!sendpage_ok(page)))

> if you run it in the kernel source tree you're using and substitute the
> paths to vmlinux and the build tree for modules.
> 
> David
>