TL-WR1043ND: USB storage accessing triggers skbuff allocation failure in ath9k

[ylxu72@…]

Kamikaze r19587, Linux version 2.6.32.7 (gcc version 4.3.3)

Step to reproduce the failure:

1. Attach a USB disk with ext3 file sytem to TL-WR1043ND, and openwrt mount it automatically
2. Try to download a file on the USB disk from an connected wifi client by ftp or samba
3. Downloading speed is unstable and may stalled for several seconds
4. SSH to WR1043ND, and find "skbuff alloc failure" in dmesg, detailed info as beneath

   skbuff alloc of size 3872 failed
   swapper: page allocation failure. order:1, mode:0x20
   Call Trace:
   [<8006851c>] dump_stack+0x8/0x34
   [<800b69e8>] __alloc_pages_nodemask+0x508/0x578
   [<800d7638>] cache_alloc_refill+0x29c/0x58c
   [<800d79cc>] __kmalloc+0xa4/0xfc
   [<801dfb40>] __alloc_skb+0x70/0x140
   [<80c72038>] ath_rxbuf_alloc+0x38/0xb8 [ath]
   [<80d05524>] ath_rx_tasklet+0x228/0x54c [ath9k]
   [<80d046c0>] ath9k_tasklet+0x60/0xec [ath9k]
   [<8008221c>] tasklet_action+0x88/0xe4
   [<80082a10>] __do_softirq+0xb0/0x148
   [<80082af0>] do_softirq+0x48/0x6c
   [<8006082c>] ret_from_irq+0x0/0x4
   [<80060a20>] r4k_wait+0x20/0x40
   [<8006cbcc>] cpu_idle+0x24/0x44
   [<802f0a48>] start_kernel+0x33c/0x354
   
   Mem-Info:
   Normal per-cpu:
   CPU    0: hi:    0, btch:   1 usd:   0
   active_anon:543 inactive_anon:550 isolated_anon:0
    active_file:924 inactive_file:1535 isolated_file:0
    unevictable:0 dirty:0 writeback:0 unstable:0
    free:265 slab_reclaimable:231 slab_unreclaimable:2364
    mapped:585 shmem:68 pagetables:65 bounce:0
   Normal free:1060kB min:720kB low:900kB high:1080kB active_anon:2172kB inactive_anon:2200kB active_file:3696kB inactive_file:6140kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:32512kB mlocked:0kB dirty:0kB writeback:0kB mapped:2340kB shmem:272kB slab_reclaimable:924kB slab_unreclaimable:9456kB kernel_stack:368kB pagetables:260kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
   lowmem_reserve[]: 0 0
   Normal: 265*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 1060kB
   2526 total pagecache pages
   0 pages in swap cache
   Swap cache stats: add 0, delete 0, find 0/0
   Free swap  = 0kB
   Total swap = 0kB
   8192 pages RAM
   852 pages reserved
   2394 pages shared
   5008 pages non-shared
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   skbuff alloc of size 3872 failed
   
   

[anonymous]

A work around found: Just change "htmode" default wireless config from "HT20" to "HT40" resloves the issue, and "skbuff alloc failure" disappear, samba/ftp downloading become stable. So, it's "HT20" htmode configuration trigger a bug in ath9k, and make the wireless unstable.

config wifi-device  radio0
	option type     mac80211
	option channel  1
	option macaddr	94:0c:ed:xx:xx:xx
	option hwmode	11ng
	option htmode	HT40
...

[anonymous]

Seeing this with htmode HT40+ here.

[anonymous]

Make sure you are using a Self Powered External Harddisk, the router does not have sufficient power to power another device.

[nbd]

sounds like an old bug that has been fixed a long time ago

[jow]

Milestone Attitude Adjustment 12.09 deleted