From: David Miller <davem@davemloft.net>
To: rdreier@cisco.com
Cc: herbert@gondor.apana.org.au, aluno3@poczta.onet.pl,
general@lists.openfabrics.org, netdev@vger.kernel.org
Subject: Re: [ofa-general] NetEffect, iw_nes and kernel warning
Date: Fri, 30 Jan 2009 13:51:07 -0800 (PST) [thread overview]
Message-ID: <20090130.135107.116108989.davem@davemloft.net> (raw)
In-Reply-To: <adaiqnwr91j.fsf@cisco.com>
From: Roland Dreier <rdreier@cisco.com>
Date: Fri, 30 Jan 2009 09:35:52 -0800
> > > OK, thanks... what confused me is that several other drivers also do
> > > skb_linearize() in their hard_start_xmit method... eg bnx2x,
> > > via-velocity, mv643xx_eth. So there are several other lurking bugs to
> > > deal with here I guess.
> >
> > I don't know about the rest but bnx2x is certainly OK since it
> > only does so with IRQ enabled. It is legal to call skb_linearize
> > as long as you're sure that IRQs are enabled, which is always the
> > case for hard_start_xmit upon entry.
>
> I don't believe this is accurate. Calling skb_linearize() (on a kernel
> with CONFIG_HIGHMEM set) can end up calling local_bh_enable() in
> kunmap_skb_frag(), which can obviously cause problems if the initial
> context relies on having BHs disabled (as hard_start_xmit does).
local_bh_{enable,disable}() nests, so this is not a problem
next prev parent reply other threads:[~2009-01-30 21:51 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <497EF9AC.70104@poczta.onet.pl>
2009-01-27 23:53 ` [ofa-general] NetEffect, iw_nes and kernel warning Roland Dreier
2009-01-28 0:07 ` David Miller
2009-01-28 0:17 ` Stephen Hemminger
2009-01-28 16:36 ` Tung, Chien Tin
2009-01-28 18:05 ` Roland Dreier
2009-01-28 19:05 ` Stephen Hemminger
2009-01-28 21:52 ` Roland Dreier
2009-01-30 6:57 ` Herbert Xu
2009-01-30 8:22 ` Eilon Greenstein
2009-01-30 16:25 ` Stephen Hemminger
2009-01-30 17:35 ` Roland Dreier
2009-01-30 21:51 ` David Miller [this message]
2009-01-31 3:54 ` Roland Dreier
2009-04-21 9:09 ` Lennert Buytenhek
2009-04-21 12:49 ` Herbert Xu
2009-04-21 12:50 ` Herbert Xu
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