On 3 Jul 2021, at 15:41, Flavio Leitner wrote:
> Hi,
>
> Thanks for fixing this bug!
>
> On Fri, Jul 02, 2021 at 10:22:36AM -0400, Eelco Chaudron wrote:
>> When TSO is disabled from a userspace forwarding datapath perspective,
>> but TSO has been wrongly enabled on the kernel side, log a warning
>> message, and drop the packet. With the current implementation,
>> OVS will crash.
>>
>> Fixes: 73858f9db ("netdev-linux: Prepend the std packet in the TSO packet")
>> Signed-off-by: Eelco Chaudron <[email protected]>
>> ---
>> lib/netdev-linux.c | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>>
>> diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
>> index 07ece0c7f..6dc98cae5 100644
>> --- a/lib/netdev-linux.c
>> +++ b/lib/netdev-linux.c
>> @@ -1303,6 +1303,23 @@ netdev_linux_batch_rxq_recv_sock(struct
>> netdev_rxq_linux *rx, int mtu,
>> continue;
>> }
>>
>> + if (mmsgs[i].msg_hdr.msg_flags & MSG_TRUNC) {
>> + /* Data is truncated, so the packet is corrupted, and needs to
>> be
>> + * dropped. This can happen if TSO/GRO is enabled in the kernel,
>> + * but not in userspace, i.e. there is no dp buffer to store the
>> + * full packet. */
>> + struct netdev *netdev_ = netdev_rxq_get_netdev(&rx->up);
>> + struct netdev_linux *netdev = netdev_linux_cast(netdev_);
>> +
>> + dp_packet_delete(buffers[i]);
>> + dp_packet_delete(rx->aux_bufs[i]);
>
> It needs to set rx->aux_bufs[i] to NULL so that the caller can
> allocate a new packet, otherwise the free pointer will be re-used
> next time.
>
> Another option is to not free that aux_bufs and let it be re-used
> next time (same happens in the block above when
> mmsgs[i].msg_len < ETH_HEADER_LEN.
I opted for the second solution, as it made to code look better.
Thanks!
>
> fbl
>
>> + netdev->rx_dropped += 1;
>> + VLOG_WARN_RL(&rl,
>> + "%s: Dropped packet: Too big. GRO/TSO
>> enabled?",
>> + netdev_get_name(netdev_));
>> + continue;
>> + }
>> +
>> if (mmsgs[i].msg_len > std_len) {
>> /* Build a single linear TSO packet by prepending the data from
>> * std_len buffer to the aux_buf. */
>>
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