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From: David Woodhouse <dwmw2@infradead.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Francois Romieu <romieu@fr.zoreil.com>,
	David Miller <davem@davemloft.net>,
	netdev@vger.kernel.org
Subject: Re: [PATCH v2 RFC] 8139cp: Fix GSO MSS handling
Date: Thu, 24 Sep 2015 13:31:38 +0100	[thread overview]
Message-ID: <1443097898.74600.91.camel@infradead.org> (raw)
In-Reply-To: <1443096325.29850.151.camel@edumazet-glaptop2.roam.corp.google.com>

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On Thu, 2015-09-24 at 05:05 -0700, Eric Dumazet wrote:
> 
> Right, netif_skb_features() only has the following checks :
> 
> if (gso_segs > dev->gso_max_segs || gso_segs < dev->gso_min_segs)
>     features &= ~NETIF_F_GSO_MASK;
> 
> But now we have .ndo_features_check() we could remove this generic 
> check from fast path.

Perhaps so, yes.

Any thoughts on the other reason I was staring at this same code path
this week? I am able to reliably feed inappropriate packets to a
NETIF_F_IP_CSUM-capable device with the test program at
http://bombadil.infradead.org/~dwmw2/raw.c (and equivalent code paths
via virtio_net, tun and others).

They're *supposed* to get checksummed by software if the device can't
cope, but netif_skb_features() returns the wrong answer, so we fail to
do that and they're fed with CHECKSUM_PARTIAL to a device which can't
handle them. Causing a WARN() or a BUG() or a silent corruption,
depending on the driver.

-- 
dwmw2


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  reply	other threads:[~2015-09-24 12:31 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-17 23:19 [PATCH 1/2] 8139cp: Use dev_kfree_skb_any() instead of dev_kfree_skb() in cp_clean_rings() David Woodhouse
2015-09-17 23:21 ` [PATCH 2/2] 8139cp: Call __cp_set_rx_mode() from cp_tx_timeout() David Woodhouse
2015-09-18 11:37   ` [PATCH 3/2] 8139cp: Improve accuracy of cp_interrupt() return, to survive IRQ storms David Woodhouse
2015-09-18 12:17   ` [PATCH 4/2] 8139cp: Do not re-enable RX interrupts in cp_tx_timeout() David Woodhouse
2015-09-21  5:24   ` [PATCH 2/2] 8139cp: Call __cp_set_rx_mode() from cp_tx_timeout() David Miller
2015-09-21 13:59     ` David Woodhouse
2015-09-21 14:01       ` [PATCH 1/7] 8139cp: Improve accuracy of cp_interrupt() return, to survive IRQ storms David Woodhouse
2015-09-21 20:25         ` Francois Romieu
2015-09-21 20:52           ` David Woodhouse
2015-09-22 23:45         ` David Miller
2015-09-23  8:14           ` David Woodhouse
2015-09-23  8:43             ` [PATCH 1/7] 8139cp: Do not re-enable RX interrupts in cp_tx_timeout() David Woodhouse
2015-09-23  8:44             ` [PATCH 2/7] 8139cp: Fix tx_queued debug message to print correct slot numbers David Woodhouse
2015-09-23  8:44             ` [PATCH 3/7] 8139cp: Fix TSO/scatter-gather descriptor setup David Woodhouse
2015-09-23  8:44             ` [PATCH 4/7] 8139cp: Reduce duplicate csum/tso code in cp_start_xmit() David Woodhouse
2015-09-23  8:45             ` [PATCH 5/7] 8139cp: Fix DMA unmapping of transmitted buffers David Woodhouse
2015-09-23  8:45             ` [PATCH 6/7] 8139cp: Dump contents of descriptor ring on TX timeout David Woodhouse
2015-09-23  8:46             ` [PATCH 7/7] 8139cp: Enable offload features by default David Woodhouse
2015-09-23 17:58             ` [PATCH 1/7] 8139cp: Improve accuracy of cp_interrupt() return, to survive IRQ storms David Miller
2015-09-23 19:45               ` David Woodhouse
2015-09-23 21:48                 ` David Miller
2015-09-23 22:00                   ` David Woodhouse
2015-09-23 23:29                     ` Francois Romieu
2015-09-24  8:58                       ` [PATCH WTF] 8139cp: Fix GSO MSS handling David Woodhouse
2015-09-24 10:38                         ` [PATCH v2 RFC] " David Woodhouse
2015-09-24 12:05                           ` Eric Dumazet
2015-09-24 12:31                             ` David Woodhouse [this message]
2015-09-28  5:37                               ` Tom Herbert
2015-09-28  7:21                                 ` David Woodhouse
2015-09-27  5:38                           ` David Miller
2015-09-23 22:02                   ` [PATCH] 8139cp: Set GSO max size and enforce it David Woodhouse
2015-09-23 22:44                 ` [PATCH 1/7] 8139cp: Improve accuracy of cp_interrupt() return, to survive IRQ storms Francois Romieu
2015-09-23 23:09                   ` David Woodhouse
2015-10-28  8:47               ` David Woodhouse
2015-09-23 22:44             ` Francois Romieu
2015-09-23 23:18               ` David Woodhouse
2015-09-21 14:02       ` [PATCH 2/7] 8139cp: Do not re-enable RX interrupts in cp_tx_timeout() David Woodhouse
2015-09-22 23:46         ` David Miller
2015-09-21 14:02       ` [PATCH 3/7] 8139cp: Fix tx_queued debug message to print correct slot numbers David Woodhouse
2015-09-21 14:02       ` [PATCH 4/7] 8139cp: Fix TSO/scatter-gather descriptor setup David Woodhouse
2015-09-21 21:01         ` Francois Romieu
2015-09-21 21:06           ` David Woodhouse
2015-09-21 21:47           ` David Woodhouse
2015-09-22 21:59             ` Francois Romieu
2015-09-21 14:03       ` [PATCH 5/7] 8139cp: Fix DMA unmapping of transmitted buffers David Woodhouse
2015-09-21 14:03       ` [PATCH 6/7] 8139cp: Dump contents of descriptor ring on TX timeout David Woodhouse
2015-09-21 14:05       ` [PATCH 7/7] 8139cp: Avoid gratuitous writes to TxPoll register when already running David Woodhouse
2015-09-21 20:54         ` Francois Romieu
2015-09-21 21:10           ` David Woodhouse
2015-09-21 14:11       ` [PATCH 2/2] 8139cp: Call __cp_set_rx_mode() from cp_tx_timeout() David Woodhouse
2015-09-21  5:24 ` [PATCH 1/2] 8139cp: Use dev_kfree_skb_any() instead of dev_kfree_skb() in cp_clean_rings() David Miller

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