netdev - Re: Requirements for a shutdown function?

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:   Tue, 9 May 2017 13:51:28 -0500
From:   Timur Tabi <timur@...eaurora.org>
To:     Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org
Subject: Re: Requirements for a shutdown function?

On 05/09/2017 01:46 PM, Florian Fainelli wrote:
> A good test case for exercising a .shutdown() function is kexec'ing a
> new kernel for instance.

I tried that.  I run iperf in one window while launching kexec in another.
Even without a shutdown function, network traffic appear to halt on its own
and the kexec succeeds.

Is it possible that the network stack detects a kexec and automatically
stops all network devices?

> You should put your HW in a state where it won't be doing DMA, or have
> any adverse side effects to the system, putting it in a low power state
> is also a good approach.

My in-house driver stops the RX and TX queues.  I'm guessing that's good
enough, but I don't have a failing test case to prove it.

-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.