I removed all linux-backports-modules-* packages and the problem is still reproducible. Again, doing "cat /dev/sda > /dev/null " causes this only when the ath9k module is loaded.
Jul 1 07:43:59 cheren kernel: [ 418.094914] __ratelimit: 6 callbacks suppressed Jul 1 07:43:59 cheren kernel: [ 418.094920] swapper: page allocation failure. order:1, mode:0x4020 Jul 1 07:43:59 cheren kernel: [ 418.094927] Pid: 0, comm: swapper Not tainted 2.6.28-13-generic #44-Ubuntu Jul 1 07:43:59 cheren kernel: [ 418.094931] Call Trace: Jul 1 07:43:59 cheren kernel: [ 418.094943] [<c04fca36>] ? printk+0x18/0x1a Jul 1 07:43:59 cheren kernel: [ 418.094951] [<c0194287>] __alloc_pages_internal+0x387/0x490 Jul 1 07:43:59 cheren kernel: [ 418.094959] [<c01b7ebc>] ? __slab_alloc+0xcc/0x260 Jul 1 07:43:59 cheren kernel: [ 418.094965] [<c01943e1>] __get_free_pages+0x21/0x40 Jul 1 07:43:59 cheren kernel: [ 418.094971] [<c01b8c2e>] __kmalloc_track_caller+0xee/0xf0 Jul 1 07:43:59 cheren kernel: [ 418.094979] [<c0427eac>] ? __alloc_skb+0x2c/0x110 Jul 1 07:43:59 cheren kernel: [ 418.094986] [<c042818c>] ? dev_alloc_skb+0x1c/0x30 Jul 1 07:43:59 cheren kernel: [ 418.094992] [<c0427ecd>] __alloc_skb+0x4d/0x110 Jul 1 07:43:59 cheren kernel: [ 418.094999] [<c042818c>] dev_alloc_skb+0x1c/0x30 Jul 1 07:43:59 cheren kernel: [ 418.095031] [<f8019bc0>] ath_rxbuf_alloc+0x20/0x80 [ath9k] Jul 1 07:43:59 cheren kernel: [ 418.095053] [<f8019c4c>] ath_rx_indicate+0x2c/0xd0 [ath9k] Jul 1 07:43:59 cheren kernel: [ 418.095074] [<f801a01d>] ath_rx_tasklet+0x32d/0x520 [ath9k] Jul 1 07:43:59 cheren kernel: [ 418.095082] [<c0119a73>] ? lapic_next_event+0x13/0x20 Jul 1 07:43:59 cheren kernel: [ 418.095104] [<f8022dee>] ath9k_tasklet+0x6e/0xa0 [ath9k] Jul 1 07:43:59 cheren kernel: [ 418.095112] [<c013ed18>] tasklet_action+0x78/0x100 Jul 1 07:43:59 cheren kernel: [ 418.095118] [<c013f197>] __do_softirq+0x97/0x170 Jul 1 07:43:59 cheren kernel: [ 418.095125] [<c011c7df>] ? ack_apic_level+0x6f/0x290 Jul 1 07:43:59 cheren kernel: [ 418.095132] [<c013f2cd>] do_softirq+0x5d/0x60 Jul 1 07:43:59 cheren kernel: [ 418.095138] [<c013f445>] irq_exit+0x55/0x90 Jul 1 07:43:59 cheren kernel: [ 418.095144] [<c0106853>] do_IRQ+0x83/0xa0 Jul 1 07:43:59 cheren kernel: [ 418.095150] [<c01051f3>] common_interrupt+0x23/0x30 Jul 1 07:43:59 cheren kernel: [ 418.095157] [<c0319467>] ? acpi_idle_enter_bm+0x269/0x2b8 Jul 1 07:43:59 cheren kernel: [ 418.095165] [<c040b44f>] cpuidle_idle_call+0x6f/0xd0 Jul 1 07:43:59 cheren kernel: [ 418.095170] [<c010285d>] cpu_idle+0x6d/0xd0 Jul 1 07:43:59 cheren kernel: [ 418.095177] [<c04ed07e>] rest_init+0x4e/0x60 Jul 1 07:43:59 cheren kernel: [ 418.095181] Mem-Info: Jul 1 07:43:59 cheren kernel: [ 418.095184] DMA per-cpu: Jul 1 07:43:59 cheren kernel: [ 418.095188] CPU 0: hi: 0, btch: 1 usd: 0 Jul 1 07:43:59 cheren kernel: [ 418.095192] CPU 1: hi: 0, btch: 1 usd: 0 Jul 1 07:43:59 cheren kernel: [ 418.095195] Normal per-cpu: Jul 1 07:43:59 cheren kernel: [ 418.095199] CPU 0: hi: 186, btch: 31 usd: 22 Jul 1 07:43:59 cheren kernel: [ 418.095203] CPU 1: hi: 186, btch: 31 usd: 31 Jul 1 07:43:59 cheren kernel: [ 418.095207] HighMem per-cpu: Jul 1 07:43:59 cheren kernel: [ 418.095210] CPU 0: hi: 42, btch: 7 usd: 0 Jul 1 07:43:59 cheren kernel: [ 418.095214] CPU 1: hi: 42, btch: 7 usd: 7 Jul 1 07:43:59 cheren kernel: [ 418.095222] Active_anon:33196 active_file:16912 inactive_anon:33295 Jul 1 07:43:59 cheren kernel: [ 418.095224] inactive_file:146758 unevictable:472 dirty:15 writeback:0 unstable:0 Jul 1 07:43:59 cheren kernel: [ 418.095226] free:5239 slab:6614 mapped:18554 pagetables:972 bounce:0 Jul 1 07:43:59 cheren kernel: [ 418.095233] DMA free:3460kB min:64kB low:80kB high:96kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:5084kB unevictable:0kB present:15764kB pages_scanned:0 all_unreclaimable? no Jul 1 07:43:59 cheren kernel: [ 418.095238] lowmem_reserve[]: 0 861 998 998 Jul 1 07:43:59 cheren kernel: [ 418.095250] Normal free:7680kB min:3720kB low:4648kB high:5580kB active_anon:118236kB inactive_anon:118428kB active_file:29852kB inactive_file:525028kB unevictable:8kB present:881880kB pages_scanned:0 all_unreclaimable? no Jul 1 07:43:59 cheren kernel: [ 418.095256] lowmem_reserve[]: 0 0 1101 1101 Jul 1 07:43:59 cheren kernel: [ 418.095268] HighMem free:9816kB min:136kB low:284kB high:432kB active_anon:14548kB inactive_anon:14752kB active_file:37796kB inactive_file:56920kB unevictable:1880kB present:141040kB pages_scanned:0 all_unreclaimable? no Jul 1 07:43:59 cheren kernel: [ 418.095274] lowmem_reserve[]: 0 0 0 0 Jul 1 07:43:59 cheren kernel: [ 418.095282] DMA: 5*4kB 0*8kB 1*16kB 1*32kB 1*64kB 0*128kB 1*256kB 0*512kB 1*1024kB 1*2048kB 0*4096kB = 3460kB Jul 1 07:43:59 cheren kernel: [ 418.095301] Normal: 1746*4kB 1*8kB 0*16kB 0*32kB 0*64kB 1*128kB 0*256kB 1*512kB 0*1024kB 0*2048kB 0*4096kB = 7632kB Jul 1 07:43:59 cheren kernel: [ 418.095320] HighMem: 523*4kB 259*8kB 87*16kB 38*32kB 14*64kB 5*128kB 2*256kB 2*512kB 0*1024kB 0*2048kB 0*4096kB = 9844kB Jul 1 07:43:59 cheren kernel: [ 418.095339] 165614 total pagecache pages Jul 1 07:43:59 cheren kernel: [ 418.095343] 28 pages in swap cache Jul 1 07:43:59 cheren kernel: [ 418.095347] Swap cache stats: add 28, delete 0, find 0/0 Jul 1 07:43:59 cheren kernel: [ 418.095350] Free swap = 1390888kB Jul 1 07:43:59 cheren kernel: [ 418.095354] Total swap = 1391000kB Jul 1 07:43:59 cheren kernel: [ 418.098839] 261840 pages RAM Jul 1 07:43:59 cheren kernel: [ 418.098839] 35538 pages HighMem Jul 1 07:43:59 cheren kernel: [ 418.098839] 13659 pages reserved Jul 1 07:43:59 cheren kernel: [ 418.098839] 229512 pages shared Jul 1 07:43:59 cheren kernel: [ 418.098839] 96616 pages non-shared Jul 1 07:43:59 cheren kernel: [ 418.098839] ath_rxbuf_alloc: skbuff alloc of size 3904 failed Jul 1 07:43:59 cheren kernel: [ 418.402297] swapper: page allocation failure. order:1, mode:0x4020 Jul 1 07:43:59 cheren kernel: [ 418.402304] Pid: 0, comm: swapper Not tainted 2.6.28-13-generic #44-Ubuntu Jul 1 07:43:59 cheren kernel: [ 418.402308] Call Trace: etc....
I removed all linux-backports -modules- * packages and the problem is still reproducible. Again, doing "cat /dev/sda > /dev/null " causes this only when the ath9k module is loaded.
Jul 1 07:43:59 cheren kernel: [ 418.094914] __ratelimit: 6 callbacks suppressed pages_internal+ 0x387/0x490 alloc+0xcc/ 0x260 pages+0x21/ 0x40 track_caller+ 0xee/0xf0 skb+0x2c/ 0x110 skb+0x1c/ 0x30 skb+0x4d/ 0x110 skb+0x1c/ 0x30 alloc+0x20/ 0x80 [ath9k] indicate+ 0x2c/0xd0 [ath9k] tasklet+ 0x32d/0x520 [ath9k] event+0x13/ 0x20 0x6e/0xa0 [ath9k] action+ 0x78/0x100 0x97/0x170 level+0x6f/ 0x290 0x5d/0x60 interrupt+ 0x23/0x30 enter_bm+ 0x269/0x2b8 idle_call+ 0x6f/0xd0 file:146758 unevictable:472 dirty:15 writeback:0 unstable:0 file:5084kB unevictable:0kB present:15764kB pages_scanned:0 all_unreclaimable? no anon:118236kB inactive_ anon:118428kB active_file:29852kB inactive_ file:525028kB unevictable:8kB present:881880kB pages_scanned:0 all_unreclaimable? no anon:14752kB active_file:37796kB inactive_ file:56920kB unevictable:1880kB present:141040kB pages_scanned:0 all_unreclaimable? no
Jul 1 07:43:59 cheren kernel: [ 418.094920] swapper: page allocation failure. order:1, mode:0x4020
Jul 1 07:43:59 cheren kernel: [ 418.094927] Pid: 0, comm: swapper Not tainted 2.6.28-13-generic #44-Ubuntu
Jul 1 07:43:59 cheren kernel: [ 418.094931] Call Trace:
Jul 1 07:43:59 cheren kernel: [ 418.094943] [<c04fca36>] ? printk+0x18/0x1a
Jul 1 07:43:59 cheren kernel: [ 418.094951] [<c0194287>] __alloc_
Jul 1 07:43:59 cheren kernel: [ 418.094959] [<c01b7ebc>] ? __slab_
Jul 1 07:43:59 cheren kernel: [ 418.094965] [<c01943e1>] __get_free_
Jul 1 07:43:59 cheren kernel: [ 418.094971] [<c01b8c2e>] __kmalloc_
Jul 1 07:43:59 cheren kernel: [ 418.094979] [<c0427eac>] ? __alloc_
Jul 1 07:43:59 cheren kernel: [ 418.094986] [<c042818c>] ? dev_alloc_
Jul 1 07:43:59 cheren kernel: [ 418.094992] [<c0427ecd>] __alloc_
Jul 1 07:43:59 cheren kernel: [ 418.094999] [<c042818c>] dev_alloc_
Jul 1 07:43:59 cheren kernel: [ 418.095031] [<f8019bc0>] ath_rxbuf_
Jul 1 07:43:59 cheren kernel: [ 418.095053] [<f8019c4c>] ath_rx_
Jul 1 07:43:59 cheren kernel: [ 418.095074] [<f801a01d>] ath_rx_
Jul 1 07:43:59 cheren kernel: [ 418.095082] [<c0119a73>] ? lapic_next_
Jul 1 07:43:59 cheren kernel: [ 418.095104] [<f8022dee>] ath9k_tasklet+
Jul 1 07:43:59 cheren kernel: [ 418.095112] [<c013ed18>] tasklet_
Jul 1 07:43:59 cheren kernel: [ 418.095118] [<c013f197>] __do_softirq+
Jul 1 07:43:59 cheren kernel: [ 418.095125] [<c011c7df>] ? ack_apic_
Jul 1 07:43:59 cheren kernel: [ 418.095132] [<c013f2cd>] do_softirq+
Jul 1 07:43:59 cheren kernel: [ 418.095138] [<c013f445>] irq_exit+0x55/0x90
Jul 1 07:43:59 cheren kernel: [ 418.095144] [<c0106853>] do_IRQ+0x83/0xa0
Jul 1 07:43:59 cheren kernel: [ 418.095150] [<c01051f3>] common_
Jul 1 07:43:59 cheren kernel: [ 418.095157] [<c0319467>] ? acpi_idle_
Jul 1 07:43:59 cheren kernel: [ 418.095165] [<c040b44f>] cpuidle_
Jul 1 07:43:59 cheren kernel: [ 418.095170] [<c010285d>] cpu_idle+0x6d/0xd0
Jul 1 07:43:59 cheren kernel: [ 418.095177] [<c04ed07e>] rest_init+0x4e/0x60
Jul 1 07:43:59 cheren kernel: [ 418.095181] Mem-Info:
Jul 1 07:43:59 cheren kernel: [ 418.095184] DMA per-cpu:
Jul 1 07:43:59 cheren kernel: [ 418.095188] CPU 0: hi: 0, btch: 1 usd: 0
Jul 1 07:43:59 cheren kernel: [ 418.095192] CPU 1: hi: 0, btch: 1 usd: 0
Jul 1 07:43:59 cheren kernel: [ 418.095195] Normal per-cpu:
Jul 1 07:43:59 cheren kernel: [ 418.095199] CPU 0: hi: 186, btch: 31 usd: 22
Jul 1 07:43:59 cheren kernel: [ 418.095203] CPU 1: hi: 186, btch: 31 usd: 31
Jul 1 07:43:59 cheren kernel: [ 418.095207] HighMem per-cpu:
Jul 1 07:43:59 cheren kernel: [ 418.095210] CPU 0: hi: 42, btch: 7 usd: 0
Jul 1 07:43:59 cheren kernel: [ 418.095214] CPU 1: hi: 42, btch: 7 usd: 7
Jul 1 07:43:59 cheren kernel: [ 418.095222] Active_anon:33196 active_file:16912 inactive_anon:33295
Jul 1 07:43:59 cheren kernel: [ 418.095224] inactive_
Jul 1 07:43:59 cheren kernel: [ 418.095226] free:5239 slab:6614 mapped:18554 pagetables:972 bounce:0
Jul 1 07:43:59 cheren kernel: [ 418.095233] DMA free:3460kB min:64kB low:80kB high:96kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_
Jul 1 07:43:59 cheren kernel: [ 418.095238] lowmem_reserve[]: 0 861 998 998
Jul 1 07:43:59 cheren kernel: [ 418.095250] Normal free:7680kB min:3720kB low:4648kB high:5580kB active_
Jul 1 07:43:59 cheren kernel: [ 418.095256] lowmem_reserve[]: 0 0 1101 1101
Jul 1 07:43:59 cheren kernel: [ 418.095268] HighMem free:9816kB min:136kB low:284kB high:432kB active_anon:14548kB inactive_
Jul 1 07:43:59 cheren kernel: [ 418.095274] lowmem_reserve[]: 0 0 0 0
Jul 1 07:43:59 cheren kernel: [ 418.095282] DMA: 5*4kB 0*8kB 1*16kB 1*32kB 1*64kB 0*128kB 1*256kB 0*512kB 1*1024kB 1*2048kB 0*4096kB = 3460kB
Jul 1 07:43:59 cheren kernel: [ 418.095301] Normal: 1746*4kB 1*8kB 0*16kB 0*32kB 0*64kB 1*128kB 0*256kB 1*512kB 0*1024kB 0*2048kB 0*4096kB = 7632kB
Jul 1 07:43:59 cheren kernel: [ 418.095320] HighMem: 523*4kB 259*8kB 87*16kB 38*32kB 14*64kB 5*128kB 2*256kB 2*512kB 0*1024kB 0*2048kB 0*4096kB = 9844kB
Jul 1 07:43:59 cheren kernel: [ 418.095339] 165614 total pagecache pages
Jul 1 07:43:59 cheren kernel: [ 418.095343] 28 pages in swap cache
Jul 1 07:43:59 cheren kernel: [ 418.095347] Swap cache stats: add 28, delete 0, find 0/0
Jul 1 07:43:59 cheren kernel: [ 418.095350] Free swap = 1390888kB
Jul 1 07:43:59 cheren kernel: [ 418.095354] Total swap = 1391000kB
Jul 1 07:43:59 cheren kernel: [ 418.098839] 261840 pages RAM
Jul 1 07:43:59 cheren kernel: [ 418.098839] 35538 pages HighMem
Jul 1 07:43:59 cheren kernel: [ 418.098839] 13659 pages reserved
Jul 1 07:43:59 cheren kernel: [ 418.098839] 229512 pages shared
Jul 1 07:43:59 cheren kernel: [ 418.098839] 96616 pages non-shared
Jul 1 07:43:59 cheren kernel: [ 418.098839] ath_rxbuf_alloc: skbuff alloc of size 3904 failed
Jul 1 07:43:59 cheren kernel: [ 418.402297] swapper: page allocation failure. order:1, mode:0x4020
Jul 1 07:43:59 cheren kernel: [ 418.402304] Pid: 0, comm: swapper Not tainted 2.6.28-13-generic #44-Ubuntu
Jul 1 07:43:59 cheren kernel: [ 418.402308] Call Trace:
etc....