请教：段错误后GDB调试没有任何信息

highnjupt

代码跑个一天左右，总出现段错误；用GDB跟了下，但是出错后GDB没有任何提示信息，打印堆栈信息也是空的。

程序中有些库是第三方提供的，没有加-g，自己能控制的部分都加了-g；

同时程序出错后也没有core信息，ulimit -s 1024 这些也都加过；

交流下什么情况下，段错误后GDB调试没有任何信息?

highnjupt

CU最近很冷啊

T-Bagwell

ulimit -c unlimited

会生成cordump

highnjupt

回复 3# T-Bagwell

谢谢版主回复，这样使用也还是产生不了
   

T-Bagwell

求文件系统格式
至少文件系统要保证能够写文件

举例

1. 
   
2. [root@centos1 c_leard]#
   
3. [root@centos1 c_leard]# ls
   
4. a  test  test2.c  test.c
   
5. [root@centos1 c_leard]# cat test2.c
   
6. #include <stdio.h>
   
7. #include <string.h>
   
8. 
   
9. void fuck2()
   
10. {
    
11.         char *test = "abcdefg";
    
12.         strcpy(test, "fuck");
    
13. }
    
14. void fuck1()
    
15. {
    
16.         fuck2();
    
17. }
    
18. void fuck ()
    
19. {
    
20.         fuck1();
    
21. }
    
22. int main()
    
23. {
    
24.         fuck();
    
25.         return ;
    
26. }
    
27. [root@centos1 c_leard]# gcc test2.c -o test2
    
28. [root@centos1 c_leard]# ulimit -c unlimited
    
29. [root@centos1 c_leard]# ./test2
    
30. Segmentation fault (core dumped)
    
31. [root@centos1 c_leard]# ls
    
32. a  core.2669  test  test2  test2.c  test.c
    
33. [root@centos1 c_leard]# gdb -c core.2669 ./test2
    
34. GNU gdb (GDB) Red Hat Enterprise Linux (7.1-29.el6)
    
35. Copyright (C) 2010 Free Software Foundation, Inc.
    
36. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
    
37. This is free software: you are free to change and redistribute it.
    
38. There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
    
39. and "show warranty" for details.
    
40. This GDB was configured as "x86_64-redhat-linux-gnu".
    
41. For bug reporting instructions, please see:
    
42. <http://www.gnu.org/software/gdb/bugs/>...
    
43. Reading symbols from /root/c_leard/test2...(no debugging symbols found)...done.
    
44. [New Thread 2669]
    
45. Missing separate debuginfo for
    
46. Try: yum --disablerepo='*' --enablerepo='*-debuginfo' install /usr/lib/debug/.build-id/e3/288ac29ed63015d8781dcf763cafadd212d6c9
    
47. Reading symbols from /lib64/libc.so.6...(no debugging symbols found)...done.
    
48. Loaded symbols for /lib64/libc.so.6
    
49. Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
    
50. Loaded symbols for /lib64/ld-linux-x86-64.so.2
    
51. Core was generated by `./test2'.
    
52. Program terminated with signal 11, Segmentation fault.
    
53. #0  0x00007fe797b4dd21 in memcpy () from /lib64/libc.so.6
    
54. Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.7.el6.x86_64
    
55. (gdb) bt
    
56. #0  0x00007fe797b4dd21 in memcpy () from /lib64/libc.so.6
    
57. #1  0x00000000004004ed in fuck2 ()
    
58. #2  0x00000000004004fd in fuck1 ()
    
59. #3  0x000000000040050d in fuck ()
    
60. #4  0x000000000040051d in main ()
    
61. (gdb)
    
62. 
    

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highnjupt

回复 5# T-Bagwell


   ext3的文件系统

写个段错误的小例程，core dump会产生
在整个代码里认为的加上段错误，gdb也能提示到相应的信息
但是整个代码跑着跑着出来段错误后，就没有任何提示信息，只有
Segmentation fault

T-Bagwell

highnjupt 发表于 2012-05-02 08:26
回复 5# T-Bagwell

请参考我的调试过程

highnjupt

回复 7# T-Bagwell

core文件产生了，之前运行的时候文件系统设置成了只读的，所以一直没有产生core文件。

core文件产生提示的是在malloc里面出了问题，GDB调试信息：

1. Program terminated with signal 11, Segmentation fault.
   
2. [New process 894]
   
3. [New process 922]
   
4. [New process 955]
   
5. [New process 892]
   
6. [New process 891]
   
7. [New process 895]
   
8. [New process 896]
   
9. [New process 916]
   
10. [New process 917]
    
11. [New process 918]
    
12. [New process 919]
    
13. [New process 923]
    
14. [New process 924]
    
15. [New process 926]
    
16. [New process 927]
    
17. [New process 949]
    
18. [New process 928]
    
19. [New process 971]
    
20. [New process 930]
    
21. [New process 978]
    
22. [New process 931]
    
23. [New process 983]
    
24. [New process 932]
    
25. [New process 984]
    
26. [New process 933]
    
27. [New process 1000]
    
28. [New process 934]
    
29. [New process 1007]
    
30. [New process 936]
    
31. [New process 1013]
    
32. [New process 893]
    
33. [New process 937]
    
34. [New process 897]
    
35. [New process 938]
    
36. [New process 941]
    
37. [New process 935]
    
38. [New process 939]
    
39. [New process 943]
    
40. [New process 921]
    
41. [New process 940]
    
42. [New process 929]
    
43. [New process 942]
    
44. [New process 914]
    
45. [New process 944]
    
46. [New process 982]
    
47. [New process 945]
    
48. [New process 925]
    
49. [New process 946]
    
50. [New process 947]
    
51. [New process 948]
    
52. [New process 1012]
    
53. [New process 950]
    
54. [New process 1004]
    
55. [New process 951]
    
56. [New process 952]
    
57. [New process 1003]
    
58. [New process 953]
    
59. [New process 954]
    
60. [New process 1002]
    
61. [New process 957]
    
62. [New process 1001]
    
63. [New process 958]
    
64. [New process 999]
    
65. [New process 959]
    
66. [New process 960]
    
67. [New process 998]
    
68. [New process 961]
    
69. [New process 997]
    
70. [New process 962]
    
71. [New process 996]
    
72. [New process 963]
    
73. [New process 995]
    
74. [New process 964]
    
75. [New process 965]
    
76. [New process 994]
    
77. [New process 966]
    
78. [New process 993]
    
79. [New process 967]
    
80. [New process 988]
    
81. [New process 968]
    
82. [New process 987]
    
83. [New process 986]
    
84. [New process 969]
    
85. [New process 985]
    
86. [New process 970]
    
87. [New process 981]
    
88. [New process 920]
    
89. [New process 980]
    
90. [New process 979]
    
91. [New process 977]
    
92. [New process 972]
    
93. [New process 976]
    
94. [New process 974]
    
95. [New process 975]
    
96. #0  0x0043fe30 in malloc ()
    
97. (gdb) bt
    
98. #0  0x0043fe30 in malloc ()
    
99. Cannot access memory at address 0xbe5ff09c

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暂时还没确定是项目中的那个模块出了问题
请教下版主：提示malloc的这种错误是指针越界了还是有野指针存在呢？

T-Bagwell

通过你的信息看出来，你这是一个很庞大的工程。。。

malloc段错误的话，一般是你在malloc之前用内存用的不对
这个问题需要你仔细看代码了

highnjupt

谢谢版主回复:wink:

确实是个比较大的工程，主要修改了和业务相关的一个库，其他的代码全是原有产品上移植过来，平台也有更换过