[ovs-git] [openvswitch/ovs] f17d53: datapath: stt: linearize in SKIP_ZERO_COPY case

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/openvswitch/ovs
  Commit: f17d533ed9e188ca1498369f12f3d66747110d19
      https://github.com/openvswitch/ovs/commit/f17d533ed9e188ca1498369f12f3d66747110d19
  Author: Neal Shrader via dev <ovs-dev at openvswitch.org>
  Date:   2018-06-25 (Mon, 25 Jun 2018)

  Changed paths:
    M datapath/linux/compat/stt.c

  Log Message:
  -----------
  datapath: stt: linearize in SKIP_ZERO_COPY case

During the investigation of a kernel panic, we encountered a condition
that triggered a kernel panic due to a large skb with an unusual
geometry.  Inside of the STT codepath, an effort is made to linearize
such packets to avoid trouble during both fragment reassembly and
segmentation in the linux networking core.

As currently implemented, kernels with CONFIG_SLUB defined will skip
this process because it does not expect an skb with a frag_list to be
present.  This patch removes the assumption, and allows these skb to
be linearized as intended.  We confirmed this corrects the panic we
encountered.

Reported-by: Johannes Erdfelt <johannes at erdfelt.com>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2018-May/046800.html
Requested-by: Pravin Shelar <pshelar at ovn.org>
Signed-off-by: Neal Shrader <neal at digitalocean.com>
Signed-off-by: Pravin Shelar <pshelar at ovn.org>



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