misleading kernel warning skb_warn_bad_offload during checksum calculation

We noticed the same kernel warning with the latest LTS kernel:

[ 159.617976] ------------[ cut here ]------------
[ 159.617987] WARNING: CPU: 3 PID: 5436 at /build/linux-Hlembm/linux-4.4.0/net/core/dev.c:2444 skb_warn_bad_offload+0xd1/0x120()
[ 159.617990] docker_gwbridge: caps=(0x000000801fdb78e9, 0x0000000000000000) len=2103 data_len=1975 gso_size=1448 gso_type=5 ip_summed=1
[ 159.617991] Modules linked in: ip_vs_rr xt_ipvs ip_vs xt_nat xt_tcpudp veth tcp_diag udp_diag inet_diag binfmt_misc vxlan ip6_udp_tunnel udp_tunnel iptable_mangle xt_mark ipt_MASQUERADE nf_nat_masquerade_ipv4 xfrm_user xfrm_algo iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 xt_addrtype iptable_filter ip_tables xt_conntrack x_tables nf_nat nf_conntrack br_netfilter bridge stp llc overlay ppdev joydev input_leds serio_raw parport_pc parport i2c_piix4 8250_fintek mac_hid ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear hid_generic usbhid hid crct10dif_pclmul crc32_pclmul ghash_clmulni_intel
[ 159.618043] aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd psmouse virtio_scsi pata_acpi floppy
[ 159.618053] CPU: 3 PID: 5436 Comm: java Tainted: G W 4.4.0-75-generic #96-Ubuntu
[ 159.618054] Hardware name: Nutanix AHV, BIOS seabios-1.7.5-11.el6 04/01/2014
[ 159.618056] 0000000000000286 0000000021eefd21 ffff88042d6c3870 ffffffff813f8493
[ 159.618058] ffff88042d6c38b8 ffffffff81d6e7b0 ffff88042d6c38a8 ffffffff81081302
[ 159.618061] ffff880395dbf500 ffff88042a1f0000 0000000000000005 ffff880395dbf500
[ 159.618063] Call Trace:
[ 159.618065] <IRQ> [<ffffffff813f8493>] dump_stack+0x63/0x90
[ 159.618075] [<ffffffff81081302>] warn_slowpath_common+0x82/0xc0
[ 159.618077] [<ffffffff8108139c>] warn_slowpath_fmt+0x5c/0x80
[ 159.618081] [<ffffffff813fe562>] ? ___ratelimit+0xa2/0xe0
[ 159.618082] [<ffffffff8172ec31>] skb_warn_bad_offload+0xd1/0x120
[ 159.618085] [<ffffffff817322ce>] __skb_gso_segment+0x7e/0xd0
[ 159.618087] [<ffffffff8173267d>] validate_xmit_skb.isra.97.part.98+0x10d/0x2b0
[ 159.618089] [<ffffffff817332b2>] __dev_queue_xmit+0x582/0x590
[ 159.618091] [<ffffffff817332d0>] dev_queue_xmit+0x10/0x20
[ 159.618094] [<ffffffff8173c568>] neigh_resolve_output+0x118/0x1c0
[ 159.618099] [<ffffffff81772b56>] ip_finish_output2+0x146/0x380
[ 159.618104] [<ffffffffc03e023d>] ? ipv4_confirm+0x7d/0x100 [nf_conntrack_ipv4]
[ 159.618106] [<ffffffff81773af6>] ip_finish_output+0x136/0x1f0
[ 159.618109] [<ffffffff817671b3>] ? nf_hook_slow+0x73/0xd0
[ 159.618111] [<ffffffff817744fe>] ip_output+0x6e/0xe0
[ 159.618114] [<ffffffff817739c0>] ? __ip_flush_pending_frames.isra.39+0x90/0x90
[ 159.618116] [<ffffffff81770143>] ip_forward_finish+0x43/0x70
[ 159.618117] [<ffffffff81770509>] ip_forward+0x399/0x480
[ 159.618119] [<ffffffff81770100>] ? ip_frag_mem+0x50/0x50
[ 159.618121] [<ffffffff8176e192>] ip_rcv_finish+0x92/0x320
[ 159.618123] [<ffffffff8176eac1>] ip_rcv+0x291/0x3a0
[ 159.618125] [<ffffffff8176e100>] ? inet_del_offload+0x40/0x40
[ 159.618126] [<ffffffff817307a4>] __net...

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1705447

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

I built Xenial and Zesty test kernels with commit b2504a5dbef. The test kernels can be downloaded from:

http://kernel.ubuntu.com/~jsalisbury/lp1705447

Can you test these kernels and see if they resolve this bug?

Thanks in advance!

Brilliant! Testing it now.

Cheers,

Tested with your test kernel and I can confirm that the problem has been resolved.

Thanks a lot!

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-xenial' to 'verification-done-xenial'. If the problem still exists, change the tag 'verification-needed-xenial' to 'verification-failed-xenial'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-zesty' to 'verification-done-zesty'. If the problem still exists, change the tag 'verification-needed-zesty' to 'verification-failed-zesty'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

Hi @malikons,

Would you be able to verify the fix with the xenial and zesty kernels on -proposed?

Thanks.

Hi,

Sorry for the delay in responding. I have tested the kernel few days ago and it is working as expected. I do not see anymore kernel warnings.

Thanks,
Shiraz

This bug was fixed in the package linux - 4.4.0-93.116

---------------
linux (4.4.0-93.116) xenial; urgency=low

  * linux: 4.4.0-93.116 -proposed tracker (LP: #1709296)

  * Creating conntrack entry failure with kernel 4.4.0-89 (LP: #1709032)
    - Revert "Revert "netfilter: synproxy: fix conntrackd interaction""
    - netfilter: nf_ct_ext: fix possible panic after nf_ct_extend_unregister

  * CVE-2017-1000112
    - Revert "udp: consistently apply ufo or fragmentation"
    - udp: consistently apply ufo or fragmentation

  * CVE-2017-1000111
    - Revert "net-packet: fix race in packet_set_ring on PACKET_RESERVE"
    - packet: fix tp_reserve race in packet_set_ring

  * kernel BUG at [tty_ldisc_reinit] mm/slub.c! (LP: #1709126)
    - tty: Simplify tty_set_ldisc() exit handling
    - tty: Reset c_line from driver's init_termios
    - tty: Handle NULL tty->ldisc
    - tty: Move tty_ldisc_kill()
    - tty: Use 'disc' for line discipline index name
    - tty: Refactor tty_ldisc_reinit() for reuse
    - tty: Destroy ldisc instance on hangup

  * atheros bt failed after S3 (LP: #1706833)
    - SAUCE: Bluetooth: Make request workqueue freezable

  * The Precision Touchpad(PTP) button sends incorrect event code (LP: #1708372)
    - HID: multitouch: handle external buttons for Precision Touchpads

  * Set CONFIG_SATA_HIGHBANK=y on armhf (LP: #1703430)
    - [Config] CONFIG_SATA_HIGHBANK=y

  * xfs slab objects (memory) leak when xfs shutdown is called (LP: #1706132)
    - xfs: fix xfs_log_ticket leak in xfs_end_io() after fs shutdown

  * Adt tests of src:linux time out often on armhf lxc containers (LP: #1705495)
    - [Packaging] tests -- reduce rebuild test to one flavour

  * CVE-2017-7495
    - ext4: fix data exposure after a crash

  * ubuntu/rsi driver downlink wifi throughput drops to 5-6 Mbps when BT
    keyboard is connected (LP: #1706991)
    - SAUCE: Redpine: enable power save by default for coex mode
    - SAUCE: Redpine: uapsd configuration changes

  * [Hyper-V] hv_netvsc: Exclude non-TCP port numbers from vRSS hashing
    (LP: #1690174)
    - hv_netvsc: Exclude non-TCP port numbers from vRSS hashing

  * ath10k doesn't report full RSSI information (LP: #1706531)
    - ath10k: add per chain RSSI reporting

  * ideapad_laptop don't support v310-14isk (LP: #1705378)
    - platform/x86: ideapad-laptop: Add several models to no_hw_rfkill

  * [8087:0a2b] Failed to load bluetooth firmware(might affect some other Intel
    bt devices) (LP: #1705633)
    - Bluetooth: btintel: Create common Intel Version Read function
    - Bluetooth: Use switch statement for Intel hardware variants
    - Bluetooth: Replace constant hw_variant from Intel Bluetooth firmware
      filename
    - Bluetooth: hci_intel: Fix firmware file name to use hw_variant
    - Bluetooth: btintel: Add MODULE_FIRMWARE entries for iBT 3.5 controllers

  * xhci_hcd: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2
    comp_code 13 (LP: #1667750)
    - xhci: Bad Ethernet performance plugged in ASM1042A host

  * OpenPower: Some multipaths temporarily have only a single path
    (LP: #1696445)
    - scsi: ses: don't get power status of SES device slot on probe

  ...

This bug was fixed in the package linux - 4.10.0-33.37

---------------
linux (4.10.0-33.37) zesty; urgency=low

  * linux: 4.10.0-33.37 -proposed tracker (LP: #1709303)

  * CVE-2017-1000112
    - Revert "udp: consistently apply ufo or fragmentation"
    - udp: consistently apply ufo or fragmentation

  * CVE-2017-1000111
    - Revert "net-packet: fix race in packet_set_ring on PACKET_RESERVE"
    - packet: fix tp_reserve race in packet_set_ring

  * ThunderX: soft lockup on 4.8+ kernels when running qemu-efi with vhost=on
    (LP: #1673564)
    - irqchip/gic-v3: Add missing system register definitions
    - arm64: KVM: Do not use stack-protector to compile EL2 code
    - KVM: arm/arm64: vgic-v3: Use PREbits to infer the number of ICH_APxRn_EL2
      registers
    - KVM: arm/arm64: vgic-v3: Fix nr_pre_bits bitfield extraction
    - arm64: Add a facility to turn an ESR syndrome into a sysreg encoding
    - KVM: arm/arm64: vgic-v3: Add accessors for the ICH_APxRn_EL2 registers
    - KVM: arm64: Make kvm_condition_valid32() accessible from EL2
    - KVM: arm64: vgic-v3: Add hook to handle guest GICv3 sysreg accesses at EL2
    - KVM: arm64: vgic-v3: Add ICV_BPR1_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_IGRPEN1_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_IAR1_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_EOIR1_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_AP1Rn_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_HPPIR1_EL1 handler
    - KVM: arm64: vgic-v3: Enable trapping of Group-1 system registers
    - KVM: arm64: Enable GICv3 Group-1 sysreg trapping via command-line
    - KVM: arm64: vgic-v3: Add ICV_BPR0_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_IGNREN0_EL1 handler
    - KVM: arm64: vgic-v3: Add misc Group-0 handlers
    - KVM: arm64: vgic-v3: Enable trapping of Group-0 system registers
    - KVM: arm64: Enable GICv3 Group-0 sysreg trapping via command-line
    - arm64: Add MIDR values for Cavium cn83XX SoCs
    - [Config] CONFIG_CAVIUM_ERRATUM_30115=y
    - arm64: Add workaround for Cavium Thunder erratum 30115
    - KVM: arm64: vgic-v3: Add ICV_DIR_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_RPR_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_CTLR_EL1 handler
    - KVM: arm64: vgic-v3: Add ICV_PMR_EL1 handler
    - KVM: arm64: Enable GICv3 common sysreg trapping via command-line
    - KVM: arm64: vgic-v3: Log which GICv3 system registers are trapped
    - arm64: KVM: Make unexpected reads from WO registers inject an undef
    - KVM: arm64: Log an error if trapping a read-from-write-only GICv3 access
    - KVM: arm64: Log an error if trapping a write-to-read-only GICv3 access

  * ibmvscsis: Do not send aborted task response (LP: #1689365)
    - target: Fix unknown fabric callback queue-full errors
    - ibmvscsis: Do not send aborted task response
    - ibmvscsis: Clear left-over abort_cmd pointers
    - ibmvscsis: Fix the incorrect req_lim_delta

  * hisi_sas performance improvements (LP: #1708734)
    - scsi: hisi_sas: define hisi_sas_device.device_id as int
    - scsi: hisi_sas: optimise the usage of hisi_hba.lock
    - scsi: hisi_sas: relocate sata_done_v2_hw()
    - scsi: hisi_sas: optimise DMA slot memory

  * hisi_sas...

I am still seeing this issue with

Linux ___ 4.4.0-93-generic #116-Ubuntu SMP Fri Aug 11 21:17:51 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

[214343.266228] ------------[ cut here ]------------
[214343.266235] WARNING: CPU: 1 PID: 10743 at /build/linux-YyUNAI/linux-4.4.0/net/core/dev.c:2445 skb_warn_bad_offload+0xd1/0x120()
[214343.266239] tg3: caps=(0x00000004000001b2, 0x0000000000000000) len=1444 data_len=1402 gso_size=1376 gso_type=2 ip_summed=0
[214343.266241] Modules linked in: nf_conntrack_netlink nfnetlink binfmt_misc rpcsec_gss_krb5 auth_rpcgss nfsv4 nfs lockd grace fscache veth ipt_MASQUERADE nf_nat_masquerade_ipv4 xfrm_user xfrm_algo xt_addrtype iptable_filter xt_conntrack br_netfilter bridge stp llc aufs xt_nat xt_tcpudp iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack ip_tables x_tables hp_wmi gpio_ich sparse_keymap ppdev intel_powerclamp coretemp kvm_intel snd_hda_codec_realtek kvm snd_hda_codec_generic snd_hda_intel irqbypass snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_timer pl2303 snd usbserial soundcore input_leds serio_raw lpc_ich i7core_edac shpchp edac_core 8250_fintek parport_pc tpm_infineon parport mac_hid ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi
[214343.266302] scsi_transport_iscsi sunrpc autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear hid_generic usbhid hid nouveau crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel mxm_wmi video aes_x86_64 i2c_algo_bit lrw ttm gf128mul glue_helper ablk_helper drm_kms_helper syscopyarea cryptd firewire_ohci sysfillrect tg3 psmouse sysimgblt fb_sys_fops firewire_core ahci ptp libahci drm crc_itu_t pps_core wmi floppy fjes
[214343.266347] CPU: 1 PID: 10743 Comm: transmission-da Tainted: G W I 4.4.0-93-generic #116-Ubuntu
[214343.266349] Hardware name: Hewlett-Packard HP Z600 Workstation/0B54h, BIOS 786G4 v03.13 10/13/2010
[214343.266351] 0000000000000286 4281c02c793d7594 ffff880313a434c8 ffffffff813f9f83
[214343.266355] ffff880313a43510 ffffffff81d6f780 ffff880313a43500 ffffffff810812f2
[214343.266358] ffff88030f710300 ffff8803114c0000 0000000000000002 ffff880310cbd6ac
[214343.266361] Call Trace:
[214343.266363] <IRQ> [<ffffffff813f9f83>] dump_stack+0x63/0x90
[214343.266373] [<ffffffff810812f2>] warn_slowpath_common+0x82/0xc0
[214343.266376] [<ffffffff8108138c>] warn_slowpath_fmt+0x5c/0x80
[214343.266381] [<ffffffff814000a2>] ? ___ratelimit+0xa2/0xe0
[214343.266385] [<ffffffff81735cd1>] skb_warn_bad_offload+0xd1/0x120
[214343.266388] [<ffffffff817393dd>] __skb_gso_segment+0xfd/0x110
[214343.266391] [<ffffffff8173971d>] validate_xmit_skb.isra.97.part.98+0x10d/0x2b0
[214343.266394] [<ffffffff817398fb>] validate_xmit_skb_list+0x3b/0x60
[214343.266399] [<ffffffff8175efca>] sch_direct_xmit+0x16a/0x220
[214343.266402] [<ffffffff8173a00d>] __dev_queue_xmit+0x23d/0x590
[214343.266405] [<ffffffff8173a370>] dev_queue_xmit+0x10/0x20
[214343.266410] [<ffffffff817436e8>] neigh_resolve_output+0x118/0x1c0
[214343.266415] [<ffffffff81779d76>] ip_finish_output2+0x146/0x380
[214343.266420] [<ffff...

@manojav, since the original bug reporter, mailkons, says this bug is now fixed, you may want to open a new separate bug to track your issue.

I am confirm that after I moved to the 4.4.0-95-generic kernel from the proposed repository this, I dont see this issue any longer.

Hello,

I still se this issue on Xenial with Kernel 4.4.0-93-generic #116-Ubuntu

The server is bare-metal.

It is just a cosmetic problem in the log files or I should upgrade as soon as possible ? I noticed the bad entries in my kern.log with my monitoring tool, but I dont see any side effect so far.

Could anyone please clarify what is the operational impact of this bug ? thanks !