netdev - Re: [PATCH net] net: sched: shrink struct qdisc_skb

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:	Thu, 18 Sep 2014 09:32:14 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Stephen Hemminger <stephen@...workplumber.org>
Cc:	Or Gerlitz <or.gerlitz@...il.com>,
	Govindarajulu Varadarajan <_govind@....com>,
	Yinghai Lu <yinghai@...nel.org>,
	David Miller <davem@...emloft.net>,
	NetDev <netdev@...r.kernel.org>, ssujith@...co.com,
	gvaradar@...co.com, "Christian Benvenuti (benve)" <benve@...co.com>
Subject: Re: [PATCH net] net: sched: shrink struct qdisc_skb_cb to 28 bytes

On Thu, 2014-09-18 at 09:26 -0700, Stephen Hemminger wrote:
> On Thu, 18 Sep 2014 08:02:05 -0700
> Eric Dumazet <eric.dumazet@...il.com> wrote:
> 
> > From: Eric Dumazet <edumazet@...gle.com>
> > 
> > We cannot make struct qdisc_skb_cb bigger without impacting IPoIB,
> > or increasing skb->cb[] size.
> > 
> > Commit e0f31d849867 ("flow_keys: Record IP layer protocol in
> > skb_flow_dissect()") broke IPoIB.
> > 
> > Only current offender is sch_choke, and this one do not need an
> > absolutely precise flow key.
> > 
> > If we store 17 bytes of flow key, its more than enough. (Its the actual
> > size of flow_keys if it was a packed structure, but we might add new
> > fields at the end of it later)
> > 
> > Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> 
> Can we add BUILD_BUG to stop next time something smacks this.

I though we had.

Maybe IPoIB lacks one.

Or, do you have an idea ?


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html