netdev - Re: virtio_net: suspicious RCU usage with xdp

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]

Date:   Fri, 26 Apr 2019 16:00:28 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     Jesper Dangaard Brouer <brouer@...hat.com>,
        "Michael S. Tsirkin" <mst@...hat.com>
Cc:     Toshiaki Makita <makita.toshiaki@....ntt.co.jp>,
        David Ahern <dsahern@...il.com>,
        Toke Høiland-Jørgensen <toke@...e.dk>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: virtio_net: suspicious RCU usage with xdp


On 2019/4/26 上午1:41, Jesper Dangaard Brouer wrote:
> It does sound like my commit 5d053f9da431 ("bpf: devmap prepare xdp
> frames for bulking") introduced this issue.  I guess we can add the RCU
> section to xdp_do_flush_map(), and then also verify that the devmap
> (and cpumap) take-down code also have appropriate RCU sections (which
> they should have).
>
> Another requirement for calling .ndo_xdp_xmit is running under NAPI
> protection,


May I know the reason for this? I'm asking since if the packet was 
redirected from tuntap, ndo_xdp_xmit()  won't be called under the 
protection of NAPI (but bh is disabled).

Thanks


> is that still satisifed for veth?
> (even when invoked via xdp_do_flush_map()).