轉自點擊打開鏈接
http://blog.chinaunix.net/uid-291731-id-3142689.html
- Unable to handle kernel NULL pointer dereference at virtual address 00000020
- pgd = 80004000
- [00000020] *pgd=00000000
- Internal error: Oops: 17 [#1] PREEMPT
- last sysfs file: /sys/devices/platform/mxsdhci.2/mmc_host/mmc0/mmc0:0001/boot_bus_config
- CPU: 0 Not tainted (2.6.35.3 #10)
- PC is at fsg_main_thread+0x144/0x730
- LR is at schedule+0x2ac/0x328
- pc : [<8025b0b4>] lr : [<802ac778>] psr: 60000013
- sp : cfcd3f88 ip : cfcd3f38 fp : cfcd3fc4
- r10: cfcd2000 r9 : cf081640 r8 : 00000200
- r7 : 80356ac8 r6 : cfcd2000 r5 : cf081678 r4 : cf081600
- r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : 00000000
- Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
- Control: 10c5387d Table: bd2a0019 DAC: 00000017
- Process file-storage-ga (pid: 871, stack limit = 0xcfcd22e8)
- Stack: (0xcfcd3f88 to 0xcfcd4000)
- 3f80: cf08167c cfcd3f98 802ac648 cf0816b0 00000000 cf029ed8
- 3fa0: cfcd3fcc 8025af70 cf081600 00000000 00000000 00000000 cfcd3ff4 cfcd3fc8
- 3fc0: 8006565c 8025af7c 00000000 00000000 cfcd3fd0 cfcd3fd0 cf029ed8 800655d8
- 3fe0: 80051d14 00000013 00000000 cfcd3ff8 80051d14 800655e4 eda8ff35 f7efad76
- Backtrace:
- [<8025af70>] (fsg_main_thread+0x0/0x730) from [<8006565c>] (kthread+0x84/0x8c)
- [<800655d8>] (kthread+0x0/0x8c) from [<80051d14>] (do_exit+0x0/0x65c)
- r7:00000013 r6:80051d14 r5:800655d8 r4:cf029ed8
- Code: e5953004 e3530001 1afffff8 e5953018 (e5932020)
- ---[ end trace 38aa9563884a33ec ]---
- kernel hacking->Kernel debugging->Compile the kernel with debug info
- 0x8025af70+0x144=0x8025b0b4
- toolchain/arm-eabi-4.4.3/bin/arm-eabi-gdb kernel/vmlinux
- (gdb) b *0x8025b0b4
- Breakpoint 1 at 0x8025b0b4 : file drivers/usb/gadget/file_storage.c, line 2750.