USB虚拟网卡，拔出后内核崩溃

qsjming

请教各位高手，最近遇到了一个奇怪的问题，如下:

1>我们使用了USB模块，它里面是采用ECM虚拟网卡 + 虚拟串口的方式，内核中添加了对这个设备的支持。主要是添加option以及cdc_ether
的编译。
2>当将这个模块从USB接口拔出时，会弹出如下的信息：
<3>cdc_ether 1-2:1.3 usb0: kevent 12 may have been dropped
<7>lowmem_reserve[]: 0 0
<7>Normal: 1*4kB (R) 1*8kB (R) 0*16kB 1*32kB (R) 1*64kB (R) 0*128kB 1*256kB (R) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 364kB
<7>973 total pagecache pages
<7>16384 pages of RAM
<7>163 free pages
<7>1153 reserved pages
<7>2407 slab pages
<7>183451 pages shared
<7>0 pages swap cached
<3>cdc_ether 1-2:1.3 usb0: kevent 2 may have been dropped
<4>swapper: page allocation failure: order:0, mode:0x20
<7>CPU: 0 PID: 0 Comm: swapper Not tainted 3.18.35 #7
<7>[<c000d290>] (unwind_backtrace) from [<c000b630>] (show_stack+0x10/0x14)
<7>[<c000b630>] (show_stack) from [<c0055dbc>] (warn_alloc_failed+0xf4/0x124)
<7>[<c0055dbc>] (warn_alloc_failed) from [<c0057f78>] (__alloc_pages_nodemask+0x72c/0x7d4)
<7>[<c0057f78>] (__alloc_pages_nodemask) from [<c02282ac>] (__netdev_alloc_frag+0x54/0x19c)
<7>[<c02282ac>] (__netdev_alloc_frag) from [<c022cf30>] (__netdev_alloc_skb+0x40/0xe4)
<7>[<c022cf30>] (__netdev_alloc_skb) from [<bf13c9b8>] (rx_submit+0x3c/0x1e0 [usbnet])
<7>[<bf13c9b8>] (rx_submit [usbnet]) from [<c01d3f78>] (__usb_hcd_giveback_urb+0x70/0xd4)
<7>[<c01d3f78>] (__usb_hcd_giveback_urb) from [<c01d4058>] (usb_giveback_urb_bh+0x7c/0xbc)
<7>[<c01d4058>] (usb_giveback_urb_bh) from [<c00173a8>] (tasklet_action+0x84/0xcc)
<7>[<c00173a8>] (tasklet_action) from [<c0016d24>] (__do_softirq+0xbc/0x200)
<7>[<c0016d24>] (__do_softirq) from [<c001709c>] (irq_exit+0x80/0xa
<7>[<c001709c>] (irq_exit) from [<c0036ab0>] (__handle_domain_irq+0x78/0x94)
<7>[<c0036ab0>] (__handle_domain_irq) from [<c000c010>] (__irq_svc+0x30/0x54)
<7>[<c000c010>] (__irq_svc) from [<c0009ee8>] (arch_cpu_idle+0x2c/0x34)
<7>[<c0009ee8>] (arch_cpu_idle) from [<c0030e4c>] (cpu_startup_entry+0xa0/0x10
<7>[<c0030e4c>] (cpu_startup_entry) from [<c039ab8c>] (start_kernel+0x2e4/0x33c)

但此时内存还是充足的，后期我换了一个更大的内存，从64M改为128M，还是出现同样的问题，请问各位有没有好的建议，急切中，谢谢。         

mm50734010

<7>Normal: 1*4kB (R) 1*8kB (R) 0*16kB 1*32kB (R) 1*64kB (R) 0*128kB 1*256kB (R) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 364kB
<7>973 total pagecache pages
<7>16384 pages of RAM
<7>163 free pages

你这个系统开没开OOM killer的，个人认为像是没有free内存的。上面显示4KB的slab只有1个，共有163个free page，属于系统内存压力很大的情况了！！而且alloc fail时的内存情况，与printk看到的内存情况是不一样的。