kernel/scripts/gdb/linux/lists.py

   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
  14 import gdb
  15
  16 from linux import utils
  17
  18 list_head = utils.CachedType("struct list_head")
  19
  20
  21 def 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
  79 class 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
  92 LxListChk()