linux-kernel - Re: [PATCH net-next v3 10/18] nvme/host: Use sendmsg(MSG_SPLICE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a1b7984a-d0a0-087c-2db9-6dbb6400a2bb@grimberg.me>
Date:   Thu, 29 Jun 2023 17:49:46 +0300
From:   Sagi Grimberg <sagi@...mberg.me>
To:     Aurelien Aptel <aaptel@...dia.com>,
        David Howells <dhowells@...hat.com>, netdev@...r.kernel.org
Cc:     Alexander Duyck <alexander.duyck@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        David Ahern <dsahern@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        Jens Axboe <axboe@...nel.dk>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        Willem de Bruijn <willemb@...gle.com>,
        Keith Busch <kbusch@...nel.org>, Jens Axboe <axboe@...com>,
        Christoph Hellwig <hch@....de>,
        Chaitanya Kulkarni <kch@...dia.com>,
        linux-nvme@...ts.infradead.org
Subject: Re: [PATCH net-next v3 10/18] nvme/host: Use
 sendmsg(MSG_SPLICE_PAGES) rather then sendpage


> Hi David,
> 
> David Howells <dhowells@...hat.com> writes:
>> When transmitting data, call down into TCP using a single sendmsg with
>> MSG_SPLICE_PAGES to indicate that content should be spliced rather than
>> performing several sendmsg and sendpage calls to transmit header, data
>> pages and trailer.
> 
> This series makes my kernel crash.
> 
>  From the current net-next main branch:
> 
> commit 9ae440b8fdd6772b6c007fa3d3766530a09c9045 (HEAD)
> Merge: b545a13ca9b2 b848b26c6672
> Author: Jakub Kicinski <kuba@...nel.org>
> Date:   Sat Jun 24 15:50:21 2023 -0700
> 
>      Merge branch 'splice-net-switch-over-users-of-sendpage-and-remove-it'
> 
> 
> Steps to reproduce:
> 
> * connect a remote nvme null block device (nvmet) with 1 IO queue to keep
>    things simple
> * open /dev/nvme0n1 with O_RDWR|O_DIRECT|O_SYNC
> * write() a 8k buffer or 4k buffer

Most likely this also reproduces with blktests?
https://github.com/osandov/blktests

simple way to check is to run:
nvme_trtype=tcp ./check nvme

This runs nvme tests over nvme-tcp.

No need for network, disk or anything. It runs
both nvme and nvmet over the lo device..