附加到目标进程

gdb -p [pid]

进入gdb了：
需要导入libpython，这里举例的python环境是源码安装3.6.5，libpython.py在源码的Tools/gdb下：

(gdb) python
>import sys
>sys.path.append('/root/Python3.6.5/Tools/gdb')
>import libpython
>end

这时就可以输入调试命令了，python常用的py-list，py-bt，py-bt-full等。
如果不知道有哪些命令，照例可以用help去查:

(gdb) help
List of classes of commands:

aliases -- Aliases of other commands
breakpoints -- Making program stop at certain points
data -- Examining data
files -- Specifying and examining files
internals -- Maintenance commands
obscure -- Obscure features
running -- Running the program
stack -- Examining the stack
status -- Status inquiries
support -- Support facilities
tracepoints -- Tracing of program execution without stopping the program
user-defined -- User-defined commands

Type "help" followed by a class name for a list of commands in that class.
Type "help all" for the list of all commands.
Type "help" followed by command name for full documentation.
Type "apropos word" to search for commands related to "word".
Command name abbreviations are allowed if unambiguous.

只输入help会列出几个帮助的类别，可以help [class]查看具体的帮助，其中通过libpython引入的也会包含在具体内容中，例如help stack如下：

(gdb) help stack
Examining the stack.
The stack is made up of stack frames.  Gdb assigns numbers to stack frames
counting from zero for the innermost (currently executing) frame.

At any time gdb identifies one frame as the "selected" frame.
Variable lookups are done with respect to the selected frame.
When the program being debugged stops, gdb selects the innermost frame.
The commands below can be used to select other frames by number or address.

List of commands:

backtrace -- Print backtrace of all stack frames
bt -- Print backtrace of all stack frames
down -- Select and print stack frame called by this one
frame -- Select and print a stack frame
py-bt -- Display the current python frame and all the frames within its call stack (if any)
py-bt-full -- Display the current python frame and all the frames within its call stack (if any)
py-down -- Select and print the python stack frame called by this one (if any)
py-up -- Select and print the python stack frame that called this one (if any)
return -- Make selected stack frame return to its caller
select-frame -- Select a stack frame without printing anything
up -- Select and print stack frame that called this one

Type "help" followed by command name for full documentation.
Type "apropos word" to search for commands related to "word".
Command name abbreviations are allowed if unambiguous.

help files:

(gdb) help files
Specifying and examining files.

List of commands:

add-symbol-file -- Load symbols from FILE
add-symbol-file-from-memory -- Load the symbols out of memory from a dynamically loaded object file
cd -- Set working directory to DIR for debugger and program being debugged
core-file -- Use FILE as core dump for examining memory and registers
directory -- Add directory DIR to beginning of search path for source files
edit -- Edit specified file or function
exec-file -- Use FILE as program for getting contents of pure memory
file -- Use FILE as program to be debugged
forward-search -- Search for regular expression (see regex(3)) from last line listed
generate-core-file -- Save a core file with the current state of the debugged process
list -- List specified function or line
load -- Dynamically load FILE into the running program
nosharedlibrary -- Unload all shared object library symbols
path -- Add directory DIR(s) to beginning of search path for object files
pwd -- Print working directory
py-list -- List the current Python source code
remote -- Manipulate files on the remote system
remote delete -- Delete a remote file
remote get -- Copy a remote file to the local system
remote put -- Copy a local file to the remote system
reverse-search -- Search backward for regular expression (see regex(3)) from last line listed
search -- Search for regular expression (see regex(3)) from last line listed
section -- Change the base address of section SECTION of the exec file to ADDR
sharedlibrary -- Load shared object library symbols for files matching REGEXP
symbol-file -- Load symbol table from executable file FILE

Type "help" followed by command name for full documentation.
Type "apropos word" to search for commands related to "word".
Command name abbreviations are allowed if unambiguous.

以“py-”开头的就是。