netdev - Re: [PATCH net-next] l2tp: give proper headroom in pppol2tp

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, 18 Oct 2011 23:34:44 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	eric.dumazet@...il.com
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH net-next] l2tp: give proper headroom in pppol2tp_xmit()

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Fri, 07 Oct 2011 17:45:57 +0200

> pppol2tp_xmit() calls skb_cow_head(skb, 2) before calling
> l2tp_xmit_skb()
> 
> Then l2tp_xmit_skb() calls again skb_cow_head(skb, large_headroom)
> 
> This patchs changes the first skb_cow_head() call to supply the needed
> headroom to make sure at most one (expensive) pskb_expand_head() is
> done.
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
> ---
> Maybe we should add a counter to help diagnose too many
> pskb_expand_head() calls...

Applied.

I think it's the kind of event that deserves a tracepoint, this way one
could use perf to notice and diagnose such problems.
--
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