[FS#941] kernel error: mt7621 -> CPU: 2 PID: 7629 at net/core/skbuff.c:4343 skb_try_coalesce

Sun Jul 30 04:30:59 PDT 2017

A new Flyspray task has been opened.  Details are below. 

User who did this - camel (camel) 

Attached to Project - LEDE Project
Summary - kernel error: mt7621 -> CPU: 2 PID: 7629 at net/core/skbuff.c:4343 skb_try_coalesce
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - hello
today tested with iperf the throughput of current lede trunk (mt7621) zbt-3526

this image:
zbt-wg3526-16M-squashfs-sysupgrade.bin	1981770aa6fc723379e978f85143767ef373b6d30ef6fee3ce18338a0bd19980	3840.2 KB	Sat Jul 29 14:07:44 2017

and got this error:

kernel error: 
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.704979] ------------[ cut here ]------------
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.709668] WARNING: CPU: 2 PID: 7629 at net/core/skbuff.c:4343 skb_try_coalesce+0x22c/0x348
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.718145] Modules linked in: pppoe ppp_async option usb_wwan pptp pppox ppp_mppe ppp_generic nf_nat_pptp nf_conntrack_pptp nf_conntrack_ipv6 iptable_nat ipt_REJECT ipt_MASQUERADE xt_time xt_tcpudp xt_tcpmss xt_statistic xt_state xt_recent xt_nat xt_multiport xt_mark xt_mac xt_limit xt_length xt_hl xt_helper xt_ecn xt_dscp xt_conntrack xt_connmark xt_connlimit xt_connbytes xt_comment xt_TCPMSS xt_REDIRECT xt_NETMAP xt_LOG xt_HL xt_DSCP xt_CT xt_CLASSIFY usbserSun Jul 30 13:24:58 2017 kern.warn kernel: [  769.789814]  nf_conntrack_netlink nf_conntrack_irc nf_conntrack_h323 nf_conntrack_broadcast ts_kmp nf_conntrack_amanda iptable_mangle iptable_filter ipt_ECN ip_tables crc_ccitt fuse sch_cake 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 mt76x2e mt7603e ledtrig_usbport mt76 mac80211 cfg80211 compat xt_set ip_set_list_set ip_set_hash_netiface ip_set_hash_netport ip_set_hash_netnet ip_Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.885965] CPU: 2 PID: 7629 Comm: iperf Not tainted 4.9.40 #0
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.891795] Stack : 00000000 00000000 80547b2a 00000032 80402a24 00000000 00000000 80540000
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.900204]         8fe9831c 804e7ea7 8047ea2c 00000002 00001dcd 80543824 00000001 80580000
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.908568]         000005a8 800699c0 00000001 80540000 804edfc4 804edfc8 80483614 8e9a9bac
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.917044]         00000003 800a78c8 00000001 80580000 000005a8 00000000 8ef60000 009a9bac
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.925429]         00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.933839]         ...
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.936324] Call Trace:
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.938838] [] show_stack+0x54/0x88
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.943215] [] dump_stack+0x84/0xc0
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.947576] [] __warn+0xe4/0x118
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.951660] [] warn_slowpath_null+0x1c/0x30
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.956735] [] skb_try_coalesce+0x22c/0x348
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.961856] [] tcp_try_coalesce+0x4c/0xd0
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.966804] [] tcp_queue_rcv+0x60/0x12c
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.971509] [] tcp_rcv_established+0x300/0x608
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.976827] [] tcp_v4_do_rcv+0xa0/0x1f8
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.981527] [] __release_sock+0xb8/0x124
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.986317] [] release_sock+0x34/0x94
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.990907] [] tcp_recvmsg+0x5ec/0x928
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  769.995579] [] inet_recvmsg+0x90/0xac
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  770.000111] [] SyS_recvfrom+0xa8/0x11c
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  770.004743] [] syscall_common+0x34/0x58
Sun Jul 30 13:24:58 2017 kern.warn kernel: [  770.009995] ---[ end trace c00a3e5617713e15 ]---

and then also 
any idea what can be the reason for it ?

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=941