From: Stephen Hemminger <shemminger@vyatta.com>
To: John Wright <john.wright@hp.com>
Cc: netdev@vger.kernel.org, Michael Chan <mchan@broadcom.com>,
Bob Montgomery <bob.montgomery@hp.com>
Subject: Re: skb_shinfo(skb)->nr_frags > 0 while skb_is_gso(skb) == 0?
Date: Tue, 6 Oct 2009 18:21:31 -0700 [thread overview]
Message-ID: <20091006182131.484d6e5a@nehalam> (raw)
In-Reply-To: <20091007010315.GA26498@neptune.jswright>
On Tue, 6 Oct 2009 19:03:15 -0600
John Wright <john.wright@hp.com> wrote:
> Hello,
>
> Bob Montgomery and I are debugging an OOPS in the bnx2 driver. The
> driver OOPSes in bnx2_tx_int(), getting a NULL pointer dereference when
> checking if the skb is GSO. (This is on 2.6.29, before is_gso was
> cached in the tx_buf (commit d62fda08), but bear with me - while kernels
> with that commit might not crash in the same place, I think we have
> discovered a bug that would manifest itself another way.)
>
> So, first, a question for someone who knows more about sk_buff's than I:
> is it reasonable/legal for an skb for which skb_is_gso(skb) == 0 to also
> have skb_shinfo(skb)->nr_frags > 0?
Yes, if driver support Scatter/Gather and Checksum offload,
TCP (especially splice) will hand fragmented frames to device.
Don't know what assumptions driver is making that could cause your
issue.
next prev parent reply other threads:[~2009-10-07 1:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-07 1:03 skb_shinfo(skb)->nr_frags > 0 while skb_is_gso(skb) == 0? John Wright
2009-10-07 1:21 ` Stephen Hemminger [this message]
2009-10-07 9:04 ` John Wright
2009-10-07 16:16 ` Stephen Hemminger
2009-10-07 1:37 ` Michael Chan
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