lkml.org 
[lkml]   [2010]   [Sep]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [Bug #16626] Machine hangs with EIP at skb_copy_and_csum_dev
    На 08.9.2010 г. 23:21, Rafael J. Wysocki написа:
    > On Wednesday, September 08, 2010, David Miller wrote:
    >> From: Jarek Poplawski<jarkao2@gmail.com>
    >> Date: Wed, 8 Sep 2010 06:20:04 +0000
    >>
    >>> We need both of them. I hope David could add this too:
    >>>
    >>> Tested-by: Plamen Petrov<pvp-lsts@fs.uni-ruse.bg>
    >>
    >> Done, and applied, thanks :-)
    >
    > Please kindly let me know when Linus gets them, so that I can close the bug.
    >
    > Rafael

    Now that both commits that fix my problems are in Linus' tree, the
    bug can be closed, but these fixes should go in 2.6.35.y, too.
    So, CCing -stable.

    Fix 1:
    > commit 3d3be4333fdf6faa080947b331a6a19bce1a4f57
    >
    > gro: fix different skb headrooms
    >
    > Packets entering GRO might have different headrooms, even for a given
    > flow (because of implementation details in drivers, like copybreak).
    > We cant force drivers to deliver packets with a fixed headroom.
    >
    > 1) fix skb_segment()
    >
    > skb_segment() makes the false assumption headrooms of fragments are same
    > than the head. When CHECKSUM_PARTIAL is used, this can give csum_start
    > errors, and crash later in skb_copy_and_csum_dev()
    >
    > 2) allocate a minimal skb for head of frag_list
    >
    > skb_gro_receive() uses netdev_alloc_skb(headroom + skb_gro_offset(p)) to
    > allocate a fresh skb. This adds NET_SKB_PAD to a padding already
    > provided by netdevice, depending on various things, like copybreak.
    >
    > Use alloc_skb() to allocate an exact padding, to reduce cache line
    > needs:
    > NET_SKB_PAD + NET_IP_ALIGN
    >
    > bugzilla : https://bugzilla.kernel.org/show_bug.cgi?id=16626
    >
    > Many thanks to Plamen Petrov, testing many debugging patches !
    > With help of Jarek Poplawski.
    >
    > Reported-by: Plamen Petrov <pvp-lsts@fs.uni-ruse.bg>
    > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
    > CC: Jarek Poplawski <jarkao2@gmail.com>
    > Signed-off-by: David S. Miller <davem@davemloft.net>

    Fix 2:
    > commit 64289c8e6851bca0e589e064c9a5c9fbd6ae5dd4
    >
    > gro: Re-fix different skb headrooms
    >
    > The patch: "gro: fix different skb headrooms" in its part:
    > "2) allocate a minimal skb for head of frag_list" is buggy. The copied
    > skb has p->data set at the ip header at the moment, and skb_gro_offset
    > is the length of ip + tcp headers. So, after the change the length of
    > mac header is skipped. Later skb_set_mac_header() sets it into the
    > NET_SKB_PAD area (if it's long enough) and ip header is misaligned at
    > NET_SKB_PAD + NET_IP_ALIGN offset. There is no reason to assume the
    > original skb was wrongly allocated, so let's copy it as it was.
    >
    > bugzilla : https://bugzilla.kernel.org/show_bug.cgi?id=16626
    > fixes commit: 3d3be4333fdf6faa080947b331a6a19bce1a4f57
    >
    > Reported-by: Plamen Petrov <pvp-lsts@fs.uni-ruse.bg>
    > Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
    > CC: Eric Dumazet <eric.dumazet@gmail.com>
    > Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
    > Tested-by: Plamen Petrov <pvp-lsts@fs.uni-ruse.bg>
    > Signed-off-by: David S. Miller <davem@davemloft.net>

    Thanks,
    Plamen
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2010-09-12 08:57    [W:0.040 / U:30.984 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site