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unwind stack for goroutine in GDB for a golang exe's core dump

I need analyze some core dump file for a server written in Golang. But I can't unwind the stack info(or even a little bit useful info) using GDB.

For example,I have a main.go, its code is:

package main

func main(){
    panic("stupid")
}

And I use the following get the core file:

ulimit -c unlimited
GOTRACEBACK=crash ./main

And then I run gdb main core.And in the gdb, the things like the following.

xxx@ubuntu:/tmp/crash$ gdb main core
GNU gdb (Ubuntu 7.12.50.20170314-0ubuntu1.1) 7.12.50.20170314-git
Copyright (C) 2017 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from main...done.
[New LWP 5735]
[New LWP 5736]
[New LWP 5738]
[New LWP 5739]
[New LWP 5737]
Core was generated by `./main'.
Program terminated with signal SIGABRT, Aborted.
#0  runtime.raise () at /usr/lib/go-1.7/src/runtime/sys_linux_amd64.s:110
110        RET
[Current thread is 1 (LWP 5735)]
(gdb) source /usr/share/go-1.7/src/runtime/runtime-gdb.py
Loading Go Runtime support.
(gdb) info goroutines
* 1 running  runtime.systemstack_switch
  2 waiting  runtime.gopark
  3 waiting  runtime.gopark
(gdb) goroutine 1 bt
Python Exception <class 'gdb.error'> You can't do that without a process to debug.: 
Error occurred in Python command: You can't do that without a process to debug.
(gdb) goroutine 1 info r
Python Exception <class 'gdb.error'> You can't do that without a process to debug.: 
Error occurred in Python command: You can't do that without a process to debug.

I find issue here but it doesn't give me a solution, so anyone can tell me how can I view the goroutine info like stack trace in a core dump?

Solution

  • Unfortunately the golang support in gdb is pretty weak. Generally it is better to use the delve debugger.

    dlv core ./hello core.546
> bt
> ls

    The command name for the delve debugger is dlv. With bt you get a backtrace and ls list the corresponding parts of the code/assembly.

    Information about the debugger can be found at https://github.com/derekparker/delve