xref: /openbmc/linux/scripts/gdb/linux/lists.py (revision 2c684d89) 
1#
2# gdb helper commands and functions for Linux kernel debugging
3#
4#  list tools
5#
6# Copyright (c) Thiebaud Weksteen, 2015
7#
8# Authors:
9#  Thiebaud Weksteen <thiebaud@weksteen.fr>
10#
11# This work is licensed under the terms of the GNU GPL version 2.
12#
13
14import gdb
15
16from linux import utils
17
18list_head = utils.CachedType("struct list_head")
19
20
21def list_check(head):
22    nb = 0
23    if (head.type == list_head.get_type().pointer()):
24        head = head.dereference()
25    elif (head.type != list_head.get_type()):
26        raise gdb.GdbError('argument must be of type (struct list_head [*])')
27    c = head
28    try:
29        gdb.write("Starting with: {}\n".format(c))
30    except gdb.MemoryError:
31        gdb.write('head is not accessible\n')
32        return
33    while True:
34        p = c['prev'].dereference()
35        n = c['next'].dereference()
36        try:
37            if p['next'] != c.address:
38                gdb.write('prev.next != current: '
39                          'current@{current_addr}={current} '
40                          'prev@{p_addr}={p}\n'.format(
41                              current_addr=c.address,
42                              current=c,
43                              p_addr=p.address,
44                              p=p,
45                          ))
46                return
47        except gdb.MemoryError:
48            gdb.write('prev is not accessible: '
49                      'current@{current_addr}={current}\n'.format(
50                          current_addr=c.address,
51                          current=c
52                      ))
53            return
54        try:
55            if n['prev'] != c.address:
56                gdb.write('next.prev != current: '
57                          'current@{current_addr}={current} '
58                          'next@{n_addr}={n}\n'.format(
59                              current_addr=c.address,
60                              current=c,
61                              n_addr=n.address,
62                              n=n,
63                          ))
64                return
65        except gdb.MemoryError:
66            gdb.write('next is not accessible: '
67                      'current@{current_addr}={current}\n'.format(
68                          current_addr=c.address,
69                          current=c
70                      ))
71            return
72        c = n
73        nb += 1
74        if c == head:
75            gdb.write("list is consistent: {} node(s)\n".format(nb))
76            return
77
78
79class LxListChk(gdb.Command):
80    """Verify a list consistency"""
81
82    def __init__(self):
83        super(LxListChk, self).__init__("lx-list-check", gdb.COMMAND_DATA,
84                                        gdb.COMPLETE_EXPRESSION)
85
86    def invoke(self, arg, from_tty):
87        argv = gdb.string_to_argv(arg)
88        if len(argv) != 1:
89            raise gdb.GdbError("lx-list-check takes one argument")
90        list_check(gdb.parse_and_eval(argv[0]))
91
92LxListChk()
93