This is a "public service announcement" not a demand for resolution.
On an Archer C7, an ar71xx, 16/128 device, recent builds off "master" fail to run reliably due to memory exhaustion. External symptoms include "slow" response to ssh, APs not coming up, and the like. logread
can show if you're impacted (assuming that the logger wasn't what was killed)
Those building off "master", which is not considered stable, production-ready code, might want to check their logs for evidence of this issue.
One example of what I've been seeing (and the same build off "lede-17.01" is stable) is in the expandable area below. It typically happens in the first minute after boot. Memory consumption under 17.01 is typically around 55-65 MB of 122 MB available.
View the log details
Thu Mar 15 13:46:02 2018 daemon.notice netifd: Network device 'wlan1-2' link is up
Thu Mar 15 13:46:02 2018 daemon.notice netifd: Network device 'wlan1-3' link is up
Thu Mar 15 13:46:02 2018 daemon.notice netifd: Network device 'wlan1-4' link is up
Thu Mar 15 13:46:02 2018 daemon.notice netifd: Network device 'wlan1-5' link is up
Thu Mar 15 13:46:02 2018 kern.info kernel: [ 38.449126] br-VLAN_84: port 4(gre4t-gt97.84) entered forwarding state
Thu Mar 15 13:46:02 2018 kern.info kernel: [ 38.455770] br-VLAN_84: topology change detected, propagating
Thu Mar 15 13:46:02 2018 kern.info kernel: [ 38.848866] br-VLAN_1010: port 5(wlan1-1) entered forwarding state
Thu Mar 15 13:46:02 2018 kern.info kernel: [ 38.855150] br-VLAN_1010: topology change detected, propagating
Thu Mar 15 13:46:02 2018 kern.info kernel: [ 39.088714] br-VLAN_84: port 5(wlan1-4) entered learning state
Thu Mar 15 13:46:03 2018 kern.info kernel: [ 39.248605] br-VLAN_1010: port 8(wlan1-5) entered learning state
Thu Mar 15 13:46:03 2018 kern.info kernel: [ 39.968149] br-VLAN_1010: port 6(wlan1-2) entered forwarding state
Thu Mar 15 13:46:03 2018 kern.info kernel: [ 39.974430] br-VLAN_1010: topology change detected, propagating
Thu Mar 15 13:46:03 2018 kern.info kernel: [ 39.980506] br-VLAN_1010: port 7(wlan1-3) entered forwarding state
Thu Mar 15 13:46:03 2018 kern.info kernel: [ 39.986776] br-VLAN_1010: topology change detected, propagating
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.660466] netifd invoked oom-killer: gfp_mask=0x24201ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD), nodemask=0, order=0, oom_score_adj=0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.672230] CPU: 0 PID: 942 Comm: netifd Not tainted 4.9.86 #0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.678161] Stack : 804b765a 00000032 00000000 00000001 87cc8cd4 80443247 803f8508 000003ae
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.686700] 804b37a0 ffffffff 00000001 00200000 00000001 800a90b0 00000000 00000004
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.695244] 00000006 80455234 803fbef8 87159ba4 00000000 800d6d8c 804b765a 00000074
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.703799] 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.712343] 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.720887] ...
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.723379] Call Trace:
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.725868] [<8006b0f0>] show_stack+0x70/0x8c
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.730319] [<80112490>] dump_header.isra.5+0x80/0x174
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.735543] [<800dc854>] oom_kill_process+0xac/0x404
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.740602] [<800dd0f4>] out_of_memory+0x3c4/0x3e8
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.745472] [<800e0698>] __alloc_pages_nodemask+0x92c/0x9a8
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.751145] [<800db450>] filemap_fault+0x404/0x5cc
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.756013] [<800f8eec>] __do_fault+0x68/0x108
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.760540] [<800fc454>] handle_mm_fault+0x448/0xb2c
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.765589] [<800713fc>] __do_page_fault+0x23c/0x468
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.770648] [<80065f40>] ret_from_exception+0x0/0x10
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.775685] Mem-Info:
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.778015] active_anon:296 inactive_anon:3 isolated_anon:0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.778015] active_file:18 inactive_file:24 isolated_file:0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.778015] unevictable:0 dirty:0 writeback:0 unstable:0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.778015] slab_reclaimable:181 slab_unreclaimable:1551
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.778015] mapped:19 shmem:13 pagetables:40 bounce:0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.778015] free:3767 free_pcp:41 free_cma:0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.809933] Node 0 active_anon:1184kB inactive_anon:12kB active_file:72kB inactive_file:96kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:76kB dirty:0kB writeback:0kB shmem:52kB writeback_tmp:0kB unstable:0kB pages_scanned:0 all_unreclaimable? yes
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.833578] Normal free:15068kB min:16384kB low:20480kB high:24576kB active_anon:1184kB inactive_anon:12kB active_file:72kB inactive_file:96kB unevictable:0kB writepending:0kB present:131072kB managed:125164kB mlocked:0kB slab_reclaimable:724kB slab_unreclaimable:6204kB kernel_stack:328kB pagetables:160kB bounce:0kB free_pcp:164kB local_pcp:164kB free_cma:0kB
Thu Mar 15 13:46:05 2018 kern.emerg kernel: lowmem_reserve[]: 0 0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.869213] Normal: 387*4kB (U) 254*8kB (U) 144*16kB (UM) 53*32kB (U) 13*64kB (U) 12*128kB (U) 4*256kB (U) 6*512kB (U) 1*1024kB (U) 0*2048kB 0*4096kB = 15068kB
Thu Mar 15 13:46:05 2018 kern.emerg kernel: 55 total pagecache pages
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.886148] 0 pages in swap cache
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.889520] Swap cache stats: add 0, delete 0, find 0/0
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.894813] Free swap = 0kB
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.897743] Total swap = 0kB
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.900665] 32768 pages RAM
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.903497] 0 pages HighMem/MovableOnly
Thu Mar 15 13:46:05 2018 kern.warn kernel: [ 40.907378] 1477 pages reserved
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.910566] [ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.919235] [ 505] 0 505 298 19 4 0 0 0 ubusd
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.927982] [ 506] 0 506 225 12 4 0 0 0 askfirst
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.936982] [ 868] 0 868 306 32 4 0 0 0 logd
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.945643] [ 885] 0 885 381 27 3 0 0 0 rpcd
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.954302] [ 942] 0 942 435 60 4 0 0 0 netifd
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.963137] [ 1012] 0 1012 266 13 4 0 0 0 dropbear
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.972148] [ 1405] 0 1405 299 15 4 0 0 0 ntpd
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.980806] [ 1493] 0 1493 883 58 5 0 0 0 uhttpd
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 40.989643] [ 2593] 0 2593 938 61 5 0 0 0 hostapd
Thu Mar 15 13:46:05 2018 kern.err kernel: [ 40.998561] Out of memory: Kill process 2593 (hostapd) score 2 or sacrifice child
Thu Mar 15 13:46:05 2018 kern.err kernel: [ 41.006155] Killed process 2593 (hostapd) total-vm:3752kB, anon-rss:236kB, file-rss:8kB, shmem-rss:0kB
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.017325] br-VLAN_1010: port 8(wlan1-5) entered disabled state
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.039605] device wlan1-5 left promiscuous mode
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.044299] br-VLAN_1010: port 8(wlan1-5) entered disabled state
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.059688] br-VLAN_84: port 5(wlan1-4) entered disabled state
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.079635] device wlan1-4 left promiscuous mode
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.084330] br-VLAN_84: port 5(wlan1-4) entered disabled state
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.099536] br-VLAN_1010: port 7(wlan1-3) entered disabled state
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.117789] device wlan1-3 left promiscuous mode
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.122487] br-VLAN_1010: port 7(wlan1-3) entered disabled state
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.140563] br-VLAN_1010: port 6(wlan1-2) entered disabled state
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.158408] device wlan1-2 left promiscuous mode
Thu Mar 15 13:46:05 2018 kern.info kernel: [ 41.163108] br-VLAN_1010: port 6(wlan1-2) entered disabled state
Thu Mar 15 13:46:05 2018 daemon.notice netifd: Network device 'wlan1-5' link is down
Thu Mar 15 13:46:08 2018 daemon.notice netifd: radio0 (2690): Segmentation fault
Thu Mar 15 13:46:08 2018 daemon.notice netifd: radio0 (2690): ./mac80211.sh: eval: line 1: can't fork
Thu Mar 15 13:46:08 2018 kern.info kernel: [ 44.780790] device wlan1-1 left promiscuous mode
Thu Mar 15 13:46:08 2018 kern.info kernel: [ 44.785583] br-VLAN_1010: port 5(wlan1-1) entered disabled state
Thu Mar 15 13:46:41 2018 kern.notice kernel: [ 77.357090] random: crng init done
Thu Mar 15 13:57:33 2018 authpriv.info dropbear[2721]: Child connection from <redacted>
Thu Mar 15 13:57:40 2018 authpriv.notice dropbear[2721]: Password auth succeeded for 'root' from <redacted>