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AC68U - WiFi failing with 380.69_0 and 380.68_4 ...

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Alex Tiedemann

Occasional Visitor
Hi,

Have an Asus AC68U router from 2014 running Asuswrt-Merlin verion 380.69_0 (just upgraded from verion 380.68_4, where i also have the problem below).

The last couple of days the WiFi, both 2.5 GHz and 5 GHz, have been failing, it becomes unresponsive and either disconnect clients, or leave clients connected and then disconnects clients, when clients are using the connection.
The connection speed drops before clients are disconnected. (See Screendump 01).

The problem first showed up running Asuswrt-Merlin version 380.68_4, tried many different WiFi setting to see weather or not it made any difference, but didn't manage to find a way to solve the problem.

Updated the firmware to Asuswrt-Merlin verion 380.69_0 but still have the problem.

When restarting the router, things are running fine, for some time, then at one point the WiFi fails.
No problem when having devices connected via cable, everything works fine, just not the WiFi.

The WiFi problem is with iPhones, Android devices, Dell and HP laptops, so all our wireless devices.

See settings for WiFi in screendumps 04, 05, 06 and 07.

Have two Guest-WiFi's setup, one 2.4 Ghz and one 5 GHz.

I have saved log info from the router in a Syslog file, and see at one point this shows up:

** Syslog Start **
23.01.2018 17:49,Warning,192.168.1.1,node 0: slabs: 3834, objs: 30665, free: 1
23.01.2018 17:49,Warning,192.168.1.1,cache: kmalloc_dma-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
23.01.2018 17:49,Warning,192.168.1.1,SLUB: Unable to allocate memory on node -1 (gfp=0x21)
23.01.2018 17:49,Warning,192.168.1.1,0 pages swap cached
23.01.2018 17:49,Warning,192.168.1.1,7057 pages shared
23.01.2018 17:49,Warning,192.168.1.1,6282 slab pages
23.01.2018 17:49,Warning,192.168.1.1,1609 reserved pages
23.01.2018 17:49,Warning,192.168.1.1,22238 free pages
23.01.2018 17:49,Warning,192.168.1.1,65536 pages of RAM
23.01.2018 17:49,Warning,192.168.1.1,Total swap = 0kB
23.01.2018 17:49,Warning,192.168.1.1,Free swap = 0kB
23.01.2018 17:49,Warning,192.168.1.1,Swap cache stats: add 0, delete 0, find 0/0
23.01.2018 17:49,Warning,192.168.1.1,0 pages in swap cache
23.01.2018 17:49,Warning,192.168.1.1,2065 total pagecache pages
23.01.2018 17:49,Warning,192.168.1.1,Normal: 62*4kB 212*8kB 311*16kB 160*32kB 64*64kB 27*128kB 2*256kB 0*512kB 2*1024kB 2*2048kB 14*4096kB = 83592kB
23.01.2018 17:49,Warning,192.168.1.1,DMA: 0*4kB 2*8kB 1*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 1*4096kB = 4128kB
23.01.2018 17:49,Warning,192.168.1.1,lowmem_reserve[]: 0 0 0
23.01.2018 17:49,Warning,192.168.1.1,Normal free:83592kB min:9456kB low:11820kB high:14184kB active_anon:5376kB inactive_anon:5908kB active_file:2920kB inactive_file:4528kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:111616kB mlocked:0kB dirty:0kB writeback:0kB mapped:4816kB shmem:812kB slab_reclaimable:644kB slab_unreclaimable:11140kB kernel_stack:560kB pagetables:676kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
23.01.2018 17:49,Warning,192.168.1.1,lowmem_reserve[]: 0 109 109
23.01.2018 17:49,Warning,192.168.1.1,DMA free:4128kB min:11020kB low:13772kB high:16528kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:130048kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:122744kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
23.01.2018 17:49,Warning,192.168.1.1,mapped:1204 shmem:203 pagetables:169 bounce:0
23.01.2018 17:49,Warning,192.168.1.1,free:21930 slab_reclaimable:161 slab_unreclaimable:33471
23.01.2018 17:49,Warning,192.168.1.1,unevictable:0 dirty:0 writeback:0 unstable:0
23.01.2018 17:49,Warning,192.168.1.1,active_file:730 inactive_file:1132 isolated_file:0
23.01.2018 17:49,Warning,192.168.1.1,active_anon:1344 inactive_anon:1477 isolated_anon:0
23.01.2018 17:49,Warning,192.168.1.1,CPU 1: hi: 42, btch: 7 usd: 38
23.01.2018 17:49,Warning,192.168.1.1,CPU 0: hi: 42, btch: 7 usd: 29
23.01.2018 17:49,Warning,192.168.1.1,Normal per-cpu:
23.01.2018 17:49,Warning,192.168.1.1,CPU 1: hi: 42, btch: 7 usd: 39
23.01.2018 17:49,Warning,192.168.1.1,CPU 0: hi: 42, btch: 7 usd: 6
23.01.2018 17:49,Warning,192.168.1.1,DMA per-cpu:
23.01.2018 17:49,Warning,192.168.1.1,Mem-info:
23.01.2018 17:49,Warning,192.168.1.1,unwind: Index not found bf015e48
23.01.2018 17:49,Warning,192.168.1.1,[<c038876c>] (_dma_rxfill+0x174/0x3d4) from [<bf015e48>] (chiprx+0xf0/0x140 [et])
23.01.2018 17:49,Warning,192.168.1.1,[<c03891f0>] (osl_pktget+0x4c/0x154) from [<c038876c>] (_dma_rxfill+0x174/0x3d4)
23.01.2018 17:49,Warning,192.168.1.1,[<c01d8ea4>] (osl_alloc_skb+0x18/0x30) from [<c03891f0>] (osl_pktget+0x4c/0x154)
23.01.2018 17:49,Warning,192.168.1.1,[<c0379f88>] (__alloc_skb+0x54/0x104) from [<c01d8ea4>] (osl_alloc_skb+0x18/0x30)
23.01.2018 17:49,Warning,192.168.1.1,[<c0377998>] (__kmalloc_track_caller+0xf8/0x108) from [<c0379f88>] (__alloc_skb+0x54/0x104)
23.01.2018 17:49,Warning,192.168.1.1,[<c0377764>] (__slab_alloc+0x794/0x814) from [<c0377998>] (__kmalloc_track_caller+0xf8/0x108)
23.01.2018 17:49,Warning,192.168.1.1,[<c009e84c>] (__alloc_pages_nodemask+0x61c/0x698) from [<c0377764>] (__slab_alloc+0x794/0x814)
23.01.2018 17:49,Warning,192.168.1.1,[<c0043ff8>] (unwind_backtrace+0x0/0xf8) from [<c009e84c>] (__alloc_pages_nodemask+0x61c/0x698)
23.01.2018 17:49,Warning,192.168.1.1,swapper: page allocation failure. order:0, mode:0x4021
** Syslog End **

Have made some screendumps when logged into the router that shows the amout of RAM used, screendump 08 and 09.

At one point i got a strange message when logging into the router, screendump 10, not the normal message when logging in, screendump 11.

Have uploaded two log files, one short and one long.

http://kiwi.as/AC68U/

Any ideas?
 
** Syslog Start **
23.01.2018 17:49,Warning,192.168.1.1,node 0: slabs: 3834, objs: 30665, free: 1
23.01.2018 17:49,Warning,192.168.1.1,cache: kmalloc_dma-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
23.01.2018 17:49,Warning,192.168.1.1,SLUB: Unable to allocate memory on node -1 (gfp=0x21)


Any ideas?
this may be a good starting point for troubleshooting:
https://www.snbforums.com/threads/unable-to-allocate-cache.40981/
http://forums.whirlpool.net.au/archive/2615512
https://en.wikipedia.org/wiki/SLUB_(software)
https://www.google.com/search?q=SLUB:+Unable+to+allocate+memory+on+node
 
Hi appleseed,

Thanks a lot, will have a look. :)

So far i have set up an old TP-Link WiFi router as a AP together with the AC68U where i have disabled WiFi.
The AC68U didn't fail so far and when i login to the AC68U it shows only 49Mb out of 250Mb of RAM used.
When WiFi is enabled in the AC68U, the usage of RAM just increases over time it looks like.
 

Attachments

  • RAMAC68U_NoWiFi.jpg
    RAMAC68U_NoWiFi.jpg
    92.2 KB · Views: 792
click on the Tools menu on the left side menu (Merlin) to check NVRAM usage to see how close you are to max (65k). If you are bumping the maximum then this is a concern.

If this is not the problem, try process of elimination since this only happens on wireless. I would shut off guest wireless and restart. check the logs. Then work backwards by eliminating devices (guest network off).

A clean install plus restart and minimal settings would be the ideal solution to start from.
 
Disable airtime fairness on both 2.4 and 5.

Default for Merlin is disabled as it causes issues.

In your screens it is enabled.

Capture.JPG
 
Hi appleseed,

Thanks.

Just tried to disable Guest Networks and had two devices connected to WiFi, one to 2.4 GHz and one to 5 GHz.
Played a video via the network on the laptop on 2,4 GHz, shortly after i got the same problem.

When no WiFi enabled, the NVRAM usage is 55287 / 65536 bytes.
When WiFi is enabled, with Guest Networks, the NVRAM usage is 55665 / 65536 bytes.
When WiFi is enabled, no Guest Networks, the NVRAM usage is 55604 / 65536 bytes.

Just after the WiFi failed, with no Guest Networks, NVRAM usage was 55604 / 65536 bytes.
But might not have taken the screendump fast enough, could be it was different when it failed.

Guest Networks means one on 2.4 GHz and one on 5 GHz.

** Syslog Start **
24.01.2018 03:07,Warning,192.168.1.1,node 0: slabs: 3833, objs: 30657, free: 0
24.01.2018 03:07,Warning,192.168.1.1,cache: kmalloc_dma-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
24.01.2018 03:07,Warning,192.168.1.1,SLUB: Unable to allocate memory on node -1 (gfp=0x21)
24.01.2018 03:07,Warning,192.168.1.1,0 pages swap cached
24.01.2018 03:07,Warning,192.168.1.1,7018 pages shared
24.01.2018 03:07,Warning,192.168.1.1,6287 slab pages
24.01.2018 03:07,Warning,192.168.1.1,1609 reserved pages
24.01.2018 03:07,Warning,192.168.1.1,22433 free pages
24.01.2018 03:07,Warning,192.168.1.1,65536 pages of RAM
24.01.2018 03:07,Warning,192.168.1.1,Total swap = 0kB
24.01.2018 03:07,Warning,192.168.1.1,Free swap = 0kB
24.01.2018 03:07,Warning,192.168.1.1,Swap cache stats: add 0, delete 0, find 0/0
24.01.2018 03:07,Warning,192.168.1.1,0 pages in swap cache
24.01.2018 03:07,Warning,192.168.1.1,1761 total pagecache pages
24.01.2018 03:07,Warning,192.168.1.1,Normal: 356*4kB 344*8kB 270*16kB 112*32kB 69*64kB 24*128kB 9*256kB 2*512kB 0*1024kB 2*2048kB 14*4096kB = 84336kB
24.01.2018 03:07,Warning,192.168.1.1,DMA: 0*4kB 3*8kB 1*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 1*4096kB = 4136kB
24.01.2018 03:07,Warning,192.168.1.1,lowmem_reserve[]: 0 0 0
24.01.2018 03:07,Warning,192.168.1.1,Normal free:84336kB min:9456kB low:11820kB high:14184kB active_anon:5620kB inactive_anon:5868kB active_file:3120kB inactive_file:3120kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:111616kB mlocked:0kB dirty:0kB writeback:0kB mapped:4924kB shmem:804kB slab_reclaimable:616kB slab_unreclaimable:11336kB kernel_stack:568kB pagetables:700kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
24.01.2018 03:07,Warning,192.168.1.1,lowmem_reserve[]: 0 109 109
24.01.2018 03:07,Warning,192.168.1.1,DMA free:4136kB min:11020kB low:13772kB high:16528kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:130048kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:122736kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
24.01.2018 03:07,Warning,192.168.1.1,mapped:1231 shmem:201 pagetables:175 bounce:0
24.01.2018 03:07,Warning,192.168.1.1,free:22118 slab_reclaimable:154 slab_unreclaimable:33518
24.01.2018 03:07,Warning,192.168.1.1,unevictable:0 dirty:0 writeback:0 unstable:0
24.01.2018 03:07,Warning,192.168.1.1,active_file:780 inactive_file:780 isolated_file:0
24.01.2018 03:07,Warning,192.168.1.1,active_anon:1405 inactive_anon:1467 isolated_anon:0
24.01.2018 03:07,Warning,192.168.1.1,CPU 1: hi: 42, btch: 7 usd: 40
24.01.2018 03:07,Warning,192.168.1.1,CPU 0: hi: 42, btch: 7 usd: 30
24.01.2018 03:07,Warning,192.168.1.1,Normal per-cpu:
24.01.2018 03:07,Warning,192.168.1.1,CPU 1: hi: 42, btch: 7 usd: 39
24.01.2018 03:07,Warning,192.168.1.1,CPU 0: hi: 42, btch: 7 usd: 6
24.01.2018 03:07,Warning,192.168.1.1,DMA per-cpu:
24.01.2018 03:07,Warning,192.168.1.1,Mem-info:
24.01.2018 03:07,Warning,192.168.1.1,unwind: Index not found bf015e48
24.01.2018 03:07,Warning,192.168.1.1,[<c038876c>] (_dma_rxfill+0x174/0x3d4) from [<bf015e48>] (chiprx+0xf0/0x140 [et])
24.01.2018 03:07,Warning,192.168.1.1,[<c03891f0>] (osl_pktget+0x4c/0x154) from [<c038876c>] (_dma_rxfill+0x174/0x3d4)
24.01.2018 03:07,Warning,192.168.1.1,[<c01d8ea4>] (osl_alloc_skb+0x18/0x30) from [<c03891f0>] (osl_pktget+0x4c/0x154)
24.01.2018 03:07,Warning,192.168.1.1,[<c0379f88>] (__alloc_skb+0x54/0x104) from [<c01d8ea4>] (osl_alloc_skb+0x18/0x30)
24.01.2018 03:07,Warning,192.168.1.1,[<c0377998>] (__kmalloc_track_caller+0xf8/0x108) from [<c0379f88>] (__alloc_skb+0x54/0x104)
24.01.2018 03:07,Warning,192.168.1.1,[<c0377764>] (__slab_alloc+0x794/0x814) from [<c0377998>] (__kmalloc_track_caller+0xf8/0x108)
24.01.2018 03:07,Warning,192.168.1.1,[<c009e84c>] (__alloc_pages_nodemask+0x61c/0x698) from [<c0377764>] (__slab_alloc+0x794/0x814)
24.01.2018 03:07,Warning,192.168.1.1,[<c0043ff8>] (unwind_backtrace+0x0/0xf8) from [<c009e84c>] (__alloc_pages_nodemask+0x61c/0x698)
24.01.2018 03:07,Warning,192.168.1.1,swapper: page allocation failure. order:0, mode:0x4021
24.01.2018 03:07,Warning,192.168.1.1,node 0: slabs: 3833, objs: 30657, free: 1
24.01.2018 03:07,Warning,192.168.1.1,cache: kmalloc_dma-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
24.01.2018 03:07,Warning,192.168.1.1,SLUB: Unable to allocate memory on node -1 (gfp=0x21)
24.01.2018 03:07,Warning,192.168.1.1,0 pages swap cached
24.01.2018 03:07,Warning,192.168.1.1,7018 pages shared
24.01.2018 03:07,Warning,192.168.1.1,6287 slab pages
24.01.2018 03:07,Warning,192.168.1.1,1609 reserved pages
24.01.2018 03:07,Warning,192.168.1.1,22433 free pages
24.01.2018 03:07,Warning,192.168.1.1,65536 pages of RAM
24.01.2018 03:07,Warning,192.168.1.1,Total swap = 0kB
24.01.2018 03:07,Warning,192.168.1.1,Free swap = 0kB
24.01.2018 03:07,Warning,192.168.1.1,Swap cache stats: add 0, delete 0, find 0/0
24.01.2018 03:07,Warning,192.168.1.1,0 pages in swap cache
24.01.2018 03:07,Warning,192.168.1.1,1761 total pagecache pages
24.01.2018 03:07,Warning,192.168.1.1,Normal: 356*4kB 344*8kB 270*16kB 112*32kB 69*64kB 24*128kB 9*256kB 2*512kB 0*1024kB 2*2048kB 14*4096kB = 84336kB
24.01.2018 03:07,Warning,192.168.1.1,DMA: 0*4kB 3*8kB 1*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 1*4096kB = 4136kB
24.01.2018 03:07,Warning,192.168.1.1,lowmem_reserve[]: 0 0 0
24.01.2018 03:07,Warning,192.168.1.1,Normal free:84336kB min:9456kB low:11820kB high:14184kB active_anon:5620kB inactive_anon:5868kB active_file:3120kB inactive_file:3120kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:111616kB mlocked:0kB dirty:0kB writeback:0kB mapped:4924kB shmem:804kB slab_reclaimable:616kB slab_unreclaimable:11336kB kernel_stack:568kB pagetables:700kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
24.01.2018 03:07,Warning,192.168.1.1,lowmem_reserve[]: 0 109 109
24.01.2018 03:07,Warning,192.168.1.1,DMA free:4136kB min:11020kB low:13772kB high:16528kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:130048kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:122736kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
24.01.2018 03:07,Warning,192.168.1.1,mapped:1231 shmem:201 pagetables:175 bounce:0
24.01.2018 03:07,Warning,192.168.1.1,free:22118 slab_reclaimable:154 slab_unreclaimable:33518
24.01.2018 03:07,Warning,192.168.1.1,unevictable:0 dirty:0 writeback:0 unstable:0
24.01.2018 03:07,Warning,192.168.1.1,active_file:780 inactive_file:780 isolated_file:0
24.01.2018 03:07,Warning,192.168.1.1,active_anon:1405 inactive_anon:1467 isolated_anon:0
24.01.2018 03:07,Warning,192.168.1.1,CPU 1: hi: 42, btch: 7 usd: 40
24.01.2018 03:07,Warning,192.168.1.1,CPU 0: hi: 42, btch: 7 usd: 30
24.01.2018 03:07,Warning,192.168.1.1,Normal per-cpu:
24.01.2018 03:07,Warning,192.168.1.1,CPU 1: hi: 42, btch: 7 usd: 39
24.01.2018 03:07,Warning,192.168.1.1,CPU 0: hi: 42, btch: 7 usd: 6
24.01.2018 03:07,Warning,192.168.1.1,DMA per-cpu:
24.01.2018 03:07,Warning,192.168.1.1,Mem-info:
24.01.2018 03:07,Warning,192.168.1.1,unwind: Index not found bf015e48
24.01.2018 03:07,Warning,192.168.1.1,[<c038876c>] (_dma_rxfill+0x174/0x3d4) from [<bf015e48>] (chiprx+0xf0/0x140 [et])
24.01.2018 03:07,Warning,192.168.1.1,[<c03891f0>] (osl_pktget+0x4c/0x154) from [<c038876c>] (_dma_rxfill+0x174/0x3d4)
24.01.2018 03:07,Warning,192.168.1.1,[<c01d8ea4>] (osl_alloc_skb+0x18/0x30) from [<c03891f0>] (osl_pktget+0x4c/0x154)
24.01.2018 03:07,Warning,192.168.1.1,[<c0379f88>] (__alloc_skb+0x54/0x104) from [<c01d8ea4>] (osl_alloc_skb+0x18/0x30)
24.01.2018 03:07,Warning,192.168.1.1,[<c0377998>] (__kmalloc_track_caller+0xf8/0x108) from [<c0379f88>] (__alloc_skb+0x54/0x104)
24.01.2018 03:07,Warning,192.168.1.1,[<c0377764>] (__slab_alloc+0x794/0x814) from [<c0377998>] (__kmalloc_track_caller+0xf8/0x108)
24.01.2018 03:07,Warning,192.168.1.1,[<c009e84c>] (__alloc_pages_nodemask+0x61c/0x698) from [<c0377764>] (__slab_alloc+0x794/0x814)
24.01.2018 03:07,Warning,192.168.1.1,[<c0043ff8>] (unwind_backtrace+0x0/0xf8) from [<c009e84c>] (__alloc_pages_nodemask+0x61c/0x698)
24.01.2018 03:07,Warning,192.168.1.1,swapper: page allocation failure. order:0, mode:0x4021
** Syslog End **
 
Hi KevTech,

Will disable Airtime Fairness and see how it goes. :)

Could actually be that i have enabled it when some iPhones had problems connecting to either 2.4 GHz or 5 GHz.
Not sure, but think that problem with the phones was resolved by setting Wireless Mode to Auto on both frequencies.
 
Too early to say, but disabled Airtime Fairness and so far no problems with the WiFi with Guest Networks enabled. :)
Will do a 5-6 hour stress-test and see how things look later. ;-)
 
Yes, looks like disabling Airtime Fairness solved the problem. :)

Will keep an eye on things for some days just to make sure. :)

Still the NVRAM usage is a bit high.
NVRAM usage 55608 / 65536 bytes.

But have no idea wheather that is ok or not, how much it goes up and down during the time the router works.

Have one VPN-Client and two VPN-Servers running, plus a 'firewall-start' file with maybe 100-120 rules in it.
All MAC's have a name attatched to them in the DHCP-Server section of LAN.
As mentioned before, two Guest-Networks.

Maybe it's time for a clean-up of things. :)

Thanks a lot. :)
 
My NVRAM usage is about the same, it's usually between 54000-58000. That's about 95% NVRAM usage. I wonder if that poster was referring to RAM, I usually have 180MB free out of 250MB.
 
Hi ForkWNY,

Thanks, good to know.

Currently have:

Memory:
Total 249.71 MB
Free 205.10 MB
Buffers 0.48 MB
Cache 6.90 MB
Swap 0.00 / 0.00 MB

Internal Storage:
NVRAM usage 56326 / 65536 bytes
JFFS 1.77 / 62.75 MB
 

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