[FS#1156] Kernel 4.9 less reliable than 4.4, at least on TP-Link Archer C7v2

[LEDE Bugs]

The following task has a new comment added:

FS#1156 - Kernel 4.9 less reliable than 4.4, at least on TP-Link Archer C7v2
User who did this - Anton van Bohemen (avbohemen)

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Wifi is not perfectly reliable on 4.4 either, but it is way better than on 4.9. At the moment I have a 4.4 kernel running and it logs the following regularly:

[195203.144306] ------------[ cut here ]------------
[195203.149228] WARNING: CPU: 0 PID: 0 at backports-2017-10-06/net/mac80211/rx.c:629 ieee80211_rx_napi+0x20c/0x910 [mac80211]()
[195203.160630] Modules linked in: ath9k ath9k_common pppoe ppp_async option ath9k_hw ath10k_pci ath10k_core ath usb_wwan sierra pppox ppp_generic nf_nat_pptp nf_conntrack_pptp nf_conntrack_ipv6 mac80211 iptable_nat ipt_REJECT ipt_MASQUERADE cfg80211 belkin_sa xt_time xt_tcpudp xt_tcpmss xt_statistic xt_state xt_recent xt_policy xt_nat xt_multiport xt_mark xt_mac xt_limit xt_length xt_hl xt_helper xt_esp xt_ecn xt_dscp xt_conntrack xt_connmark xt_connlimit xt_connbytes xt_comment xt_TCPMSS xt_REDIRECT xt_LOG xt_HL xt_DSCP xt_CLASSIFY usbserial usblp ums_usbat ums_sddr55 ums_sddr09 ums_karma ums_jumpshot ums_isd200 ums_freecom ums_datafab ums_cypress ums_alauda ts_fsm ts_bm slhc nf_reject_ipv4 nf_nat_tftp nf_nat_snmp_basic nf_nat_sip nf_nat_rtsp nf_nat_redirect nf_nat_proto_gre nf_nat_masquerade_ipv4 nf_nat_irc nf_conntrack_ipv4 nf_nat_ipv4 nf_nat_h323 nf_nat_ftp nf_nat_amanda nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_tftp nf_conntrack_snmp nf_conntrack_sip nf_conntrack_rtsp nf_conntrack_rtcache nf_conntrack_proto_gre nf_conntrack_netlink nf_conntrack_irc nf_conntrack_h323 nf_conntrack_ftp nf_conntrack_broadcast ts_kmp nf_conntrack_amanda iptable_mangle iptable_filter ipt_ah ipt_ECN ip_tables crc_ccitt compat fuse sch_cake em_cmp sch_teql em_nbyte sch_pie sch_gred act_ipt cls_basic sch_red sch_prio sch_codel em_meta act_police em_text sch_sfq sch_dsmark sch_fq act_connmark nf_conntrack act_skbedit act_mirred em_u32 cls_u32 cls_tcindex cls_flow cls_route cls_fw sch_tbf sch_htb sch_hfsc sch_ingress sg ledtrig_usbport ledtrig_gpio xt_set ip_set_list_set ip_set_hash_netiface ip_set_hash_netport ip_set_hash_netnet ip_set_hash_net ip_set_hash_netportnet ip_set_hash_mac ip_set_hash_ipportnet ip_set_hash_ipportip ip_set_hash_ipport ip_set_hash_ipmark ip_set_hash_ip ip_set_bitmap_port ip_set_bitmap_ipmac ip_set_bitmap_ip ip_set nfnetlink ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables x_tables ifb sit ipcomp6 xfrm6_tunnel xfrm6_mode_tunnel xfrm6_mode_transport xfrm6_mode_beet esp6 ah6 ipcomp xfrm4_tunnel xfrm4_mode_tunnel xfrm4_mode_transport xfrm4_mode_beet esp4 ah4 tunnel6 tunnel4 ip_tunnel tun af_key xfrm_user xfrm_ipcomp xfrm_algo vfat fat ntfs nls_utf8 nls_iso8859_15 nls_iso8859_1 nls_cp850 nls_cp437 sha512_generic sha256_generic sha1_generic jitterentropy_rng drbg md5 hmac echainiv des_generic deflate zlib_inflate zlib_deflate cbc authenc mmc_block usb_storage mmc_core ohci_platform ohci_hcd ehci_platform sd_mod scsi_mod ehci_hcd gpio_button_hotplug ext4 jbd2 mbcache exfat usbcore nls_base usb_common crc16 aead crypto_null cryptomgr crc32c_generic crypto_hash
[195203.397945] CPU: 0 PID: 0 Comm: swapper Tainted: G        W       4.4.93 #0
[195203.405098] Stack : 803dd420 00000000 00000001 80430000 8042719c 80426e23 803bf024 00000000
[195203.405098]           8049378c 00000001 00000004 85a08558 00000000 800a6ab0 803c4f14 80420000
[195203.405098]           00000003 00000001 803c3320 87c09d50 00000000 800a4aa8 0000010a 00000000
[195203.405098]           80425f50 80490000 00000000 00000000 00000000 00000000 00000000 00000000
[195203.405098]           00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[195203.405098]           ...
[195203.441531] Call Trace:
[195203.444112] [] show_stack+0x70/0x8c
[195203.448627] [] warn_slowpath_common+0xa0/0xd0
[195203.454025] [] warn_slowpath_null+0x18/0x24
[195203.459334] [] ieee80211_rx_napi+0x20c/0x910 [mac80211]
[195203.465677] [] ath_rx_tasklet+0xc2c/0xdac [ath9k]
[195203.471442] [] ath9k_tasklet+0x180/0x1f0 [ath9k]
[195203.477110] [] tasklet_action+0x8c/0xc4
[195203.481982] [] __do_softirq+0x164/0x290
[195203.486851] [] plat_irq_dispatch+0xf8/0x10c
[195203.492077] [] handle_int+0x138/0x144
[195203.496773] [] r4k_wait_irqoff+0x18/0x20
[195203.501731] [] cpu_startup_entry+0xc4/0xec
[195203.506876] [] start_kernel+0x468/0x488
[195203.511737]
[195203.513342] ---[ end trace 5309fa5d5309fa5d ]---
[195203.521017] ath10k_pci 0000:01:00.0: SWBA overrun on vdev 0, skipped old beacon
[195203.528557] ath10k_pci 0000:01:00.0: SWBA overrun on vdev 0, skipped old beacon
[195203.536096] ath10k_pci 0000:01:00.0: SWBA overrun on vdev 0, skipped old beacon
[195203.543620] ath10k_pci 0000:01:00.0: SWBA overrun on vdev 0, skipped old beacon

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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1156#comment3802