核心空間與使用者空間列印調用棧

核心中列印調用棧

do_page_fault

info [ft2CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 801bcf00, ra == 801c0210
Oops[#1]:
CPU: 0 PID: 14190 Comm: date Not tainted 3.10.27+ #71
task: 8fd70600 ti: 88e9a000 task.ti: 88e9a000
$ 0   : 00000000 1000d000 8fee1eb8 8f5d9eb8
$ 4   : 00000000 80578b44 fffffffc 8fee1eb9
$ 8   : 00003bc4 e340f3f2 2d04acbd 562b5c3d
$12   : 00000000 00000000 00000000 00000000
$16   : 8ff05eb8 80578b44 00000002 80523478
$20   : 805b0000 80578b38 8ff05eb8 00000001
$24   : 00000000 77635ea4                  
$28   : 88e9a000 88e9bb78 8052471c 801c0210
Hi    : 00000000
Lo    : 000006cc
epc   : 801bcf00 0x801bcf00
    Not tainted
ra    : 801c0210 0x801c0210
Status: 1000d000
Cause : 0000400c
BadVA : 00000000
PrId  : 0000dc02
Process date (pid: 14190, threadinfo=88e9a000, task=8fd70600, tls=7796b460)
Stack : 8fd93040 00000000 00000006 805799a8 80578b38 8ff05eb8 00000002 80040478
          80578b30 80578b30 3b9aca00 80523478 80578b30 80578b30 3b9aca00 80040fbc
          805e0000 8004f91c 805ac528 00000000 00000000 00000000 a9d4a3c2 0e961d43
          562b9802 1045a0af 8fd70600 00000000 00000000 00000000 00000000 88e677f8
          805b0000 80524708 8052471c 8002b3c4 8fd70600 00000000 00000000 00000000
          ...
Call Trace:[<80040478>] 0x80040478
[<80040fbc>] 0x80040fbc
[<8004f91c>] 0x8004f91c
[<805b0000>] 0x805b0000
[<8002b3c4>] 0x8002b3c4
[<8002b40c>] 0x8002b40c
[<800548c4>] 0x800548c4
[<80054934>] 0x80054934
[<80059368>] 0x80059368
[<80016400>] 0x80016400
[<80010ab8>] 0x80010ab8
[<80059aa4>] 0x80059aa4
[<801f9f40>] 0x801f9f40
[<8005cc84>] 0x8005cc84
[<801c3284>] 0x801c3284
[<80059368>] 0x80059368
[<80013968>] 0x80013968
[<80012860>] 0x80012860
[<8007c774>] 0x8007c774
[<80018e98>] 0x80018e98
[<801c3260>] 0x801c3260
[<8007c938>] 0x8007c938
[<801bd644>] 0x801bd644
[<800180e8>] 0x800180e8
[<80081674>] 0x80081674
[<801bd784>] 0x801bd784
[<801c3284>] 0x801c3284
[<8007498c>] 0x8007498c
[<8007fb5c>] 0x8007fb5c
[<80012864>] 0x80012864


Code: 34470001  ac440004  ac620008 <ac870000> 8c480000  01063824  ac680000  10e00008  ac430000 
_test_uart:226]: uart test!
inf---[ end trace 21a2434fd3af4cbd ]---
o [ft2_test_uart:236]: uart testKernel panic - not syncing: Fatal exception in interrupt
 ok!      

核心在發生crash的時候會列印上面這段資訊，對應到核心中的代碼的流程是：

do_page_fault
    __do_page_fault                        arch/rlx/mm/fault.c
        die
            show_register       arch/rlx/kernel/traps.c
                __show_regs
                show_stacktrace -> show_backtrace
                show_code
        if (in_interrupt())
            panic("Fatal exception in interrupt");      

dump_stack

dump_stack用于核心調試，列印核心堆棧段資訊，需要在核心中配置DEBUG_KERNEL，可以在自己寫的driver中加上這句話來檢視函數調用流程。

注意在使用dump_stack要加上這兩個頭檔案：

#include <linux/kprobes.h>
#include <asm/traps.h>      

BUG()\WARN()

使用者空間中列印調用棧

__builtin_frame_address(int level)

backtrace()和backtrace_symbols()

參考文章

1. ​​dump_stack的簡單使用​​
2. ​​Linux Call Trace原理分析​​