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From:   David Howells <dhowells@redhat.com>
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To:     Tariq Toukan <ttoukan.linux@gmail.com>
Cc:     dhowells@redhat.com, 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>
Subject: Re: [PATCH net-next v10 08/16] tls: Inline do_tcp_sendpages()
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Date:   Wed, 07 Jun 2023 16:03:37 +0100
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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

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