I do get this message with the utopic kernel with the v9 firmware:
[  394.569319] ------------[ cut here ]------------
[  394.569358] WARNING: CPU: 0 PID: 1290 at /build/buildd/linux-3.16.0/drivers/net/wireless/iwlwifi/mvm/tx.c:191 iwl_mvm_set_tx_params+0x5da/0x6d0 [iwlmvm]()
[  394.569361] Got an HT rate for a non data frame 0x8
[  394.569363] Modules linked in: ipt_REJECT xt_CHECKSUM nfnetlink_log iptable_mangle nfnetlink xt_tcpudp xt_addrtype xt_conntrack ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack bridge stp llc aufs iptable_filter ip_tables x_tables ctr ccm dm_crypt uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core v4l2_common joydev videodev media hid_rmi dell_wmi sparse_keymap intel_rapl x86_pkg_temp_thermal btusb intel_powerclamp coretemp kvm_intel arc4 hid_multitouch kvm dell_laptop dcdbas crct10dif_pclmul snd_soc_rt5640 crc32_pclmul snd_soc_rl6231 snd_soc_core ghash_clmulni_intel snd_compress dm_multipath snd_pcm_dmaengine snd_hda_codec_realtek snd_seq_midi scsi_dh snd_hda_codec_hdmi snd_hda_codec_generic snd_seq_midi_event aesni_intel snd_hda_intel snd_hda_controller
[  394.569429]  snd_hda_codec snd_hwdep snd_rawmidi aes_x86_64 iwlmvm lrw gf128mul glue_helper mac80211 ablk_helper cryptd snd_pcm iwlwifi serio_raw cfg80211 mei_me lpc_ich mei shpchp snd_seq snd_seq_device snd_timer snd i2c_hid soundcore snd_soc_sst_acpi i2c_designware_platform dw_dmac dw_dmac_core 8250_dw i2c_designware_core spi_pxa2xx_platform rfcomm bnep bluetooth 6lowpan_iphc intel_smartconnect mac_hid binfmt_misc parport_pc ppdev lp parport btrfs xor raid6_pq hid_logitech_dj usbhid hid i915 i2c_algo_bit drm_kms_helper ahci drm libahci psmouse wmi sdhci_acpi sdhci video
[  394.569494] CPU: 0 PID: 1290 Comm: wpa_supplicant Not tainted 3.16.0-24-generic #32-Ubuntu
[  394.569497] Hardware name: Dell Inc. XPS13 9333/      , BIOS A04 03/19/2014
[  394.569500]  0000000000000009 ffff8802129e7808 ffffffff8177fcbc ffff8802129e7850
[  394.569506]  ffff8802129e7840 ffffffff8106fd8d ffff8801edc06f00 ffff880212bdc678
[  394.569510]  ffff8801ee335826 ffff880211ed9848 ffff880036186900 ffff8802129e78a0
[  394.569516] Call Trace:
[  394.569530]  [<ffffffff8177fcbc>] dump_stack+0x45/0x56
[  394.569540]  [<ffffffff8106fd8d>] warn_slowpath_common+0x7d/0xa0
[  394.569546]  [<ffffffff8106fdfc>] warn_slowpath_fmt+0x4c/0x50
[  394.569565]  [<ffffffffc066f093>] ? iwl_mvm_set_tx_params+0x43/0x6d0 [iwlmvm]
[  394.569579]  [<ffffffffc066f62a>] iwl_mvm_set_tx_params+0x5da/0x6d0 [iwlmvm]
[  394.569593]  [<ffffffffc066f974>] iwl_mvm_tx_skb+0x54/0x400 [iwlmvm]
[  394.569605]  [<ffffffffc0668a92>] iwl_mvm_mac_tx+0xb2/0x1c0 [iwlmvm]
[  394.569641]  [<ffffffffc05e8190>] __ieee80211_tx+0x2b0/0x3b0 [mac80211]
[  394.569668]  [<ffffffffc05ea816>] ieee80211_tx+0xc6/0x110 [mac80211]
[  394.569693]  [<ffffffffc05eaa4a>] ieee80211_xmit+0x9a/0xf0 [mac80211]
[  394.569717]  [<ffffffffc05eb205>] ieee80211_subif_start_xmit+0x505/0xd70 [mac80211]
[  394.569727]  [<ffffffff81680845>] dev_hard_start_xmit+0x335/0x5d0
[  394.569738]  [<ffffffff8166e1ce>] ? __alloc_skb+0x8e/0x1f0
[  394.569745]  [<ffffffff816a2546>] sch_direct_xmit+0xa6/0x210
[  394.569750]  [<ffffffff81680cda>] __dev_queue_xmit+0x1fa/0x4f0
[  394.569754]  [<ffffffff81680fe0>] dev_queue_xmit+0x10/0x20
[  394.569761]  [<ffffffff81763227>] packet_sendmsg+0xf57/0x1070
[  394.569770]  [<ffffffff81340000>] ? aa_label_is_subset+0x30/0xb0
[  394.569775]  [<ffffffff81664aad>] sock_sendmsg+0x8d/0xc0
[  394.569780]  [<ffffffff816638e9>] ? move_addr_to_user+0xb9/0xe0
[  394.569788]  [<ffffffff811fcc97>] ? evict+0x117/0x1a0
[  394.569794]  [<ffffffff811f778f>] ? __d_free+0x3f/0x60
[  394.569799]  [<ffffffff811fee73>] ? __fdget+0x13/0x20
[  394.569804]  [<ffffffff81665041>] SYSC_sendto+0x121/0x1c0
[  394.569809]  [<ffffffff81665fd2>] ? __sys_recvmsg+0x42/0x80
[  394.569815]  [<ffffffff81665a7e>] SyS_sendto+0xe/0x10
[  394.569821]  [<ffffffff81787ced>] system_call_fastpath+0x1a/0x1f
[  394.569824] ---[ end trace 9d834241ac5f7d7a ]---