Bartvz, thanks a lot.
I just installed r3636. Seems to be quite alright, but the snag came around:
Wed Mar 8 20:47:43 2017 kern.warn kernel: [ 38.150000] WARNING: CPU: 1 PID: 2769 at net/core/skbuff.c:4194 skb_try_coalesce+0x228/0x35c()
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.170000] Modules linked in: pppoe ppp_async pppox ppp_generic 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_TEE xt_TCPMSS xt_REDIRECT xt_LOG xt_HL xt_DSCP xt_CLASSIFY slhc nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_conntrack_ipvWed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.400000] CPU: 1 PID: 2769 Comm: uhttpd Not tainted 4.4.50 #0
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.410000] Stack : 00000000 00000000 804c6862 00000033 00000000 00000000 80460000 804e0000
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.410000] 86c76b6c 80461c83 803df43c 00000001 00000ad1 804c367c 87c19d3f 804fade0
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.410000] 00000000 8006320c 80460000 804e0000 80466188 8046618c 803e4070 87c19bec
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.410000] 00000003 80060fc8 87c19d3f 804fade0 00000000 000000da 00000000 00c19bec
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.410000] 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.410000] ...
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.480000] Call Trace:
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.490000] [<8001671c>] show_stack+0x6c/0x88
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.500000] [<801b1010>] dump_stack+0x8c/0xc0
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.510000] [<8002b944>] warn_slowpath_common+0xa0/0xd0
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.520000] [<8002b9fc>] warn_slowpath_null+0x18/0x24
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.530000] [<8028bff8>] skb_try_coalesce+0x228/0x35c
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.540000] [<802e73c0>] tcp_try_coalesce+0x70/0xd4
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.550000]
Wed Mar 8 20:47:44 2017 kern.warn kernel: [ 38.550000] ---[ end trace 55743a95a3379d01 ]---
Jimzhong reported a similar issue here: https://forum.openwrt.org/t/lede-v17-01-0-rc1/1285/6 - it is attributed to relayd - this is quite possible, as I use WDS (this is the WDS server router).
The official stable 17.01.0 is much worse, it either hangs or reboots after a while (reported here: https://bugs.lede-project.org/index.php?do=details&task_id=606)
Anyway, I'll test it for a couple of days and will came back with the results.
Keep up the good work and thanks a lot