netdev - Re: [drivers/net/vxlan]Why rcu_read_lock is not obtained before rculist travelling

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: <CAM_iQpUp+nmLW2i3Gm2YQnq+_EA5ozvgO33fG6k=x+kQx9kt_Q@mail.gmail.com>
Date:   Tue, 28 Feb 2017 13:29:17 -0800
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     颜小波 <yanxb123@....com>
Cc:     Stephen Hemminger <stephen@...workplumber.org>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [drivers/net/vxlan]Why rcu_read_lock is not obtained before
 rculist travelling

On Tue, Feb 28, 2017 at 6:03 AM, 颜小波 <yanxb123@....com> wrote:
> But I don’t find any rcu_read_lock invoked before travelling fdb_head list.  In vxlan_xmit and vxlan_snoop function, vxlan_find_mac function is called to search the vxlan_fdb of the dst_mac or src_mac. Then information in vxlan_fdb  is used for further process.  But as no rcu_read_lock is obtained before the list travelling, I am wondering if it is possible that vxlan_fdb is freed when it is being used.
>

In both RX and TX paths, rcu read lock is acquired by upper layer.
Check __dev_queue_xmit() and process_backlog().