netdev - Re: [PATCH net 1/5] ibmvnic: harden interrupt handler

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: <20170125.230413.830821835017116629.davem@davemloft.net>
Date:   Wed, 25 Jan 2017 23:04:13 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     tlfalcon@...ux.vnet.ibm.com
Cc:     netdev@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        wvoigt@...ibm.com, nfont@...ux.vnet.ibm.com,
        jallen@...ux.vnet.ibm.com
Subject: Re: [PATCH net 1/5] ibmvnic: harden interrupt handler

From: Thomas Falcon <tlfalcon@...ux.vnet.ibm.com>
Date: Wed, 25 Jan 2017 15:02:19 -0600

> Move most interrupt handler processing into a tasklet, and
> introduce a delay after re-enabling interrupts to fix timing
> issues encountered in hardware testing.
> 
> Signed-off-by: Thomas Falcon <tlfalcon@...ux.vnet.ibm.com>

I don't think you have any idea what the real problem is.  This looks
like a hack, at best.  Next patch you'll increase the delay to "20",
right?  And if that doesn't work you'll try "40".

Or if you do know the reason, you need to explain it in detail in this
commit message so that we can properly evaluate this patch.

Furthermore, if you're going to move all of your packet processing
into software interrupt context, you might as well use NAPI polling
which is a purposefully built piece of infrastructure for doing
exactly this.