Issue:
when the 7265 intel wireless card is used as AP, a kernel msg occurs after the 2nd wifi device connects, and stops working / message continue appearing in loop until all devices stop connecting. Module unload/reload (iwlmvm + iwlwifi) resets it.
I can reproduce this every time.


This is the kernel message/dmesg output:

 kernel: WARNING: CPU: 0 PID: 283 at drivers/net/wireless/intel/iwlwifi/mvm/tx.c:1377 iwl_mvm_rx_tx_cmd+0x36a/0x880 [iwlmvm]
 kernel: Modules linked in: veth ccm nf_conntrack_netlink xfrm_user xfrm_algo xt_addrtype br_netfilter xt_CHECKSUM tun ebtable_filter ebtables devlink overlay bridge stp llc ip6t_REJECT nf_reject_ipv6 ip6table_filter ip6t_rpfilter ip6table_raw ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6_tables xt_mark xt_connmark iptable_mangle xt_NFLOG xt_limit ipt_REJECT nf_reject_ipv4 xt_tcpudp xt_owner xt_recent xt_conntrack iptable_filter ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack nfnetlink_log libcrc32c nfnetlink intel_rapl x86_pkg_temp_thermal intel_powerclamp kvm_intel arc4 kvm irqbypass crct10dif_pclmul nls_iso8859_1 snd_hda_codec_hdmi nls_cp437 crc32_pclmul vfat fat joydev ghash_clmulni_intel iwlmvm mousedev pcbc
 kernel:  input_leds i915 mac80211 aesni_intel ofpart led_class aes_x86_64 hid_generic cmdlinepart snd_hda_codec_realtek cdc_ether iwlwifi intel_spi_platform crypto_simd 8812au(O) snd_hda_codec_generic intel_spi cryptd snd_hda_intel usbnet spi_nor iTCO_wdt glue_helper i2c_algo_bit iTCO_vendor_support snd_hda_codec mtd intel_cstate r8152 intel_uncore drm_kms_helper snd_hda_core intel_rapl_perf pcspkr mii cfg80211 drm usbhid snd_hwdep evdev hid snd_pcm rfkill rtc_cmos intel_gtt snd_timer e1000e agpgart mei_me mac_hid snd syscopyarea sysfillrect sysimgblt lpc_ich fb_sys_fops i2c_i801 mei soundcore shpchp coretemp msr ip_tables x_tables ext4 crc32c_generic crc16 mbcache jbd2 fscrypto sd_mod ahci libahci ehci_pci xhci_pci libata xhci_hcd ehci_hcd crc32c_intel scsi_mod usbcore usb_common
 kernel: CPU: 0 PID: 283 Comm: irq/47-iwlwifi Tainted: G        W  O      4.17.3-1-ARCH #1
 kernel: Hardware name:  /NUC5i5RYB, BIOS RYBDWi35.86A.0367.2017.0929.1059 09/29/2017
 kernel: RIP: 0010:iwl_mvm_rx_tx_cmd+0x36a/0x880 [iwlmvm]
 kernel: RSP: 0018:ffffa743014cfd30 EFLAGS: 00010246
 kernel: RAX: ffff88a47a753001 RBX: ffff88a5528bb100 RCX: 0000000000252c00
 kernel: RDX: 0000000000252a00 RSI: ffff88a556c28300 RDI: fffff34ec5e9d480
 kernel: RBP: ffff88a540add528 R08: ffff88a5528bb130 R09: ffffffffc0ebdf00
 kernel: R10: 000000017933d000 R11: ffffffffbd398aa0 R12: 0000000000000008
 kernel: R13: 0000000000000088 R14: 000000000000dea0 R15: ffff88a47933d000
 kernel: FS:  0000000000000000(0000) GS:ffff88a556c00000(0000) knlGS:0000000000000000
 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 kernel: CR2: 00007ffe088bfbe8 CR3: 000000025200a006 CR4: 00000000003606f0
 kernel: Call Trace:
 kernel:  ? iwl_pcie_gen2_tx_init+0x140/0x140 [iwlwifi]
 kernel:  iwl_pcie_rx_handle+0x235/0x9c0 [iwlwifi]
 kernel:  iwl_pcie_irq_handler+0x6ff/0xbc0 [iwlwifi]
 kernel:  ? irq_forced_thread_fn+0x70/0x70
 kernel:  ? irq_thread_dtor+0x80/0x80
 kernel:  irq_thread_fn+0x1f/0x50
 kernel:  ? irq_forced_thread_fn+0x70/0x70
 kernel:  irq_thread+0x142/0x1a0
 kernel:  ? wake_threads_waitq+0x30/0x30
 kernel:  kthread+0x112/0x130
 kernel:  ? kthread_flush_work_fn+0x10/0x10
 kernel:  ret_from_fork+0x35/0x40
 kernel: Code: 24 1e 00 41 89 c5 89 44 24 18 48 8d 44 24 30 48 39 c3 0f 84 7b 02 00 00 41 8d 45 ff 44 88 64 24 1f 66 89 44 24 1c e9 db 00 00 00 <0f> 0b 81 4b 28 00 01 00 00 45 31 e4 48 8b 45 10 48 8b b0 c0 03
 kernel: ---[ end trace 7ebddccc8edac4c3 ]---


# Additional information
kernel 4.17.3

## Boot msg / firmware version
 kernel: iwlwifi 0000:02:00.0: Detected Intel(R) Dual Band Wireless AC 7265, REV=0x210
 kernel: iwlwifi 0000:02:00.0: loaded firmware version 29.1044073957.0 op_mode iwlmvm


##module parameters for iwlwifi 
    11n_disable         = "1"
    amsdu_size          = "0"
    antenna_coupling    = "0"
    bt_coex_active      = "N"
    d0i3_disable        = "Y"
    d0i3_timeout        = "1000"
    debug               = "0"
    disable_11ac        = "Y"
    fw_monitor          = "N"
    fw_restart          = "Y"
    lar_disable         = "N"
    led_mode            = "0"
    nvm_file            = "(null)"
    power_level         = "0"
    power_save          = "N"
    swcrypto            = "1"
    uapsd_disable       = "3"

## for iwlmvm
    init_dbg            = "N"
    power_scheme        = "2"
    tfd_q_hang_detect   = "Y"


## lspci -k
02:00.0 Network controller: Intel Corporation Wireless 7265 (rev 59)
        Subsystem: Intel Corporation Dual Band Wireless-AC 7265
        Kernel driver in use: iwlwifi
        Kernel modules: iwlwifi

## iw event -t
returns nothing

## hostapd setup

ssid=REDACTED
wpa_passphrase=REDACTED
interface=iwlmvm0
driver=nl80211
hw_mode=g
country_code=US
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
channel=9
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_key_mgmt=WPA-PSK