[4.9,04/78] net: Fix gro aggregation for udp encaps with zero csum

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Daniel Borkmann <daniel@iogearbox.net>

commit 89e5c58fc1e2857ccdaae506fb8bc5fed57ee063 upstream.

We noticed a GRO issue for UDP-based encaps such as vxlan/geneve when the
csum for the UDP header itself is 0. In that case, GRO aggregation does
not take place on the phys dev, but instead is deferred to the vxlan/geneve
driver (see trace below).

The reason is essentially that GRO aggregation bails out in udp_gro_receive()
for such case when drivers marked the skb with CHECKSUM_UNNECESSARY (ice, i40e,
others) where for non-zero csums 2abb7cdc0dc8 ("udp: Add support for doing
checksum unnecessary conversion") promotes those skbs to CHECKSUM_COMPLETE
and napi context has csum_valid set. This is however not the case for zero
UDP csum (here: csum_cnt is still 0 and csum_valid continues to be false).

At the same time 57c67ff4bd92 ("udp: additional GRO support") added matches
on !uh->check ^ !uh2->check as part to determine candidates for aggregation,
so it certainly is expected to handle zero csums in udp_gro_receive(). The
purpose of the check added via 662880f44203 ("net: Allow GRO to use and set
levels of checksum unnecessary") seems to catch bad csum and stop aggregation
right away.

One way to fix aggregation in the zero case is to only perform the !csum_valid
check in udp_gro_receive() if uh->check is infact non-zero.

Before:

  [...]
  swapper     0 [008]   731.946506: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100400 len=1500   (1)
  swapper     0 [008]   731.946507: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100200 len=1500
  swapper     0 [008]   731.946507: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497101100 len=1500
  swapper     0 [008]   731.946508: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497101700 len=1500
  swapper     0 [008]   731.946508: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497101b00 len=1500
  swapper     0 [008]   731.946508: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100600 len=1500
  swapper     0 [008]   731.946508: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100f00 len=1500
  swapper     0 [008]   731.946509: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100a00 len=1500
  swapper     0 [008]   731.946516: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100500 len=1500
  swapper     0 [008]   731.946516: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100700 len=1500
  swapper     0 [008]   731.946516: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497101d00 len=1500   (2)
  swapper     0 [008]   731.946517: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497101000 len=1500
  swapper     0 [008]   731.946517: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497101c00 len=1500
  swapper     0 [008]   731.946517: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497101400 len=1500
  swapper     0 [008]   731.946518: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100e00 len=1500
  swapper     0 [008]   731.946518: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497101600 len=1500
  swapper     0 [008]   731.946521: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff966497100800 len=774
  swapper     0 [008]   731.946530: net:netif_receive_skb: dev=test_vxlan skbaddr=0xffff966497100400 len=14032 (1)
  swapper     0 [008]   731.946530: net:netif_receive_skb: dev=test_vxlan skbaddr=0xffff966497101d00 len=9112  (2)
  [...]

  # netperf -H 10.55.10.4 -t TCP_STREAM -l 20
  MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.55.10.4 () port 0 AF_INET : demo
  Recv   Send    Send
  Socket Socket  Message  Elapsed
  Size   Size    Size     Time     Throughput
  bytes  bytes   bytes    secs.    10^6bits/sec

   87380  16384  16384    20.01    13129.24

After:

  [...]
  swapper     0 [026]   521.862641: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff93ab0d479000 len=11286 (1)
  swapper     0 [026]   521.862643: net:netif_receive_skb: dev=test_vxlan skbaddr=0xffff93ab0d479000 len=11236 (1)
  swapper     0 [026]   521.862650: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff93ab0d478500 len=2898  (2)
  swapper     0 [026]   521.862650: net:netif_receive_skb: dev=enp10s0f0  skbaddr=0xffff93ab0d479f00 len=8490  (3)
  swapper     0 [026]   521.862653: net:netif_receive_skb: dev=test_vxlan skbaddr=0xffff93ab0d478500 len=2848  (2)
  swapper     0 [026]   521.862653: net:netif_receive_skb: dev=test_vxlan skbaddr=0xffff93ab0d479f00 len=8440  (3)
  [...]

  # netperf -H 10.55.10.4 -t TCP_STREAM -l 20
  MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.55.10.4 () port 0 AF_INET : demo
  Recv   Send    Send
  Socket Socket  Message  Elapsed
  Size   Size    Size     Time     Throughput
  bytes  bytes   bytes    secs.    10^6bits/sec

   87380  16384  16384    20.01    24576.53

Fixes: 57c67ff4bd92 ("udp: additional GRO support")
Fixes: 662880f44203 ("net: Allow GRO to use and set levels of checksum unnecessary")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Tom Herbert <tom@herbertland.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20210226212248.8300-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/udp_offload.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Message ID	20210315135212.212795602@linuxfoundation.org
State	New
Headers	show Return-Path: <stable-owner@kernel.org> From: gregkh@linuxfoundation.org To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, stable@vger.kernel.org, Daniel Borkmann <daniel@iogearbox.net>, Eric Dumazet <edumazet@google.com>, Jesse Brandeburg <jesse.brandeburg@intel.com>, Tom Herbert <tom@herbertland.com>, Willem de Bruijn <willemb@google.com>, John Fastabend <john.fastabend@gmail.com>, Jakub Kicinski <kuba@kernel.org> Subject: [PATCH 4.9 04/78] net: Fix gro aggregation for udp encaps with zero csum Date: Mon, 15 Mar 2021 14:51:27 +0100 Message-Id: <20210315135212.212795602@linuxfoundation.org> In-Reply-To: <20210315135212.060847074@linuxfoundation.org> References: <20210315135212.060847074@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	None \| expand [4.9,03/78] ath9k: fix transmitting to stations in dynamic SMPS mode [4.9,04/78] net: Fix gro aggregation for udp encaps with zero csum [4.9,05/78] net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0 [4.9,06/78] can: skb: can_skb_set_owner(): fix ref counting if socket was closed before setting s... [4.9,12/78] net/mlx4_en: update moderation when config reset [4.9,13/78] net: sched: avoid duplicates in classes dump [4.9,15/78] net: davicom: Fix regulator not turned off on failed probe [4.9,18/78] udf: fix silent AED tagLocation corruption [4.9,21/78] powerpc/perf: Record counter overflow always if SAMPLE_IP is unset [4.9,22/78] PCI: xgene-msi: Fix race in installing chained irq handler [4.9,23/78] s390/smp: __smp_rescan_cpus() - move cpumask away from stack [4.9,25/78] ALSA: hda/hdmi: Cancel pending works before suspend [4.9,27/78] ALSA: usb-audio: Fix "cannot get freq eq" errors on Dell AE515 sound bar [4.9,28/78] s390/dasd: fix hanging DASD driver unbind [4.9,32/78] usb: gadget: f_uac2: always increase endpoint max_packet_size by one audio slot [4.9,34/78] xhci: Improve detection of device initiated wake signal. [4.9,35/78] USB: serial: io_edgeport: fix memory leak in edge_startup [4.9,38/78] USB: serial: cp210x: add some more GE USB IDs [4.9,39/78] usbip: fix stub_dev to check for stream socket [4.9,43/78] usbip: fix vhci_hcd attach_store() races leading to gpf [4.9,45/78] staging: rtl8188eu: prevent ->ssid overflow in rtw_wx_set_scan() [4.9,46/78] staging: rtl8712: unterminated string leads to read overflow [4.9,47/78] staging: rtl8188eu: fix potential memory corruption in rtw_check_beacon_data() [4.9,48/78] staging: ks7010: prevent buffer overflow in ks_wlan_set_scan() [4.9,50/78] staging: rtl8192e: Fix possible buffer overflow in _rtl92e_wx_set_scan [4.9,51/78] staging: comedi: addi_apci_1032: Fix endian problem for COS sample [4.9,52/78] staging: comedi: addi_apci_1500: Fix endian problem for command sample [4.9,53/78] staging: comedi: adv_pci1710: Fix endian problem for AI command data [4.9,54/78] staging: comedi: das6402: Fix endian problem for AI command data [4.9,56/78] staging: comedi: dmm32at: Fix endian problem for AI command data [4.9,58/78] staging: comedi: pcl711: Fix endian problem for AI command data [4.9,59/78] staging: comedi: pcl818: Fix endian problem for AI command data [4.9,63/78] configfs: fix a use-after-free in __configfs_open_file [4.9,65/78] alpha: add $(src)/ rather than $(obj)/ to make source file path [4.9,66/78] alpha: merge build rules of division routines [4.9,67/78] alpha: make short build log available for division routines [4.9,68/78] alpha: Package string routines together [4.9,69/78] alpha: switch __copy_user() and __do_clean_user() to normal calling conventions [4.9,70/78] powerpc/64s: Fix instruction encoding for lis in ppc_function_entry() [4.9,72/78] hwmon: (lm90) Fix max6658 sporadic wrong temperature reading [4.9,73/78] KVM: arm64: Fix exclusive limit for IPA size [4.9,75/78] iio: imu: adis16400: fix memory leak [4.9,78/78] xen/events: avoid handling the same event on two cpus at the same time

[4.9,04/78] net: Fix gro aggregation for udp encaps with zero csum

Commit Message

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