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db7fbf492d
If the list is uninitialized (next pointer is NULL), list_for_each gets stuck in an infinite loop. Print a message and treat list as empty. Link: https://lkml.kernel.org/r/4ae23bb1-c333-f669-da2d-fa35c4f49018@amazon.com Signed-off-by: George Prekas <prekageo@amazon.com> Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com> Cc: Kieran Bingham <kbingham@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
136 lines
4.2 KiB
Python
136 lines
4.2 KiB
Python
#
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# gdb helper commands and functions for Linux kernel debugging
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#
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# list tools
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#
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# Copyright (c) Thiebaud Weksteen, 2015
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#
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# Authors:
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# Thiebaud Weksteen <thiebaud@weksteen.fr>
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#
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# This work is licensed under the terms of the GNU GPL version 2.
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#
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import gdb
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from linux import utils
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list_head = utils.CachedType("struct list_head")
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hlist_head = utils.CachedType("struct hlist_head")
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hlist_node = utils.CachedType("struct hlist_node")
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def list_for_each(head):
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if head.type == list_head.get_type().pointer():
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head = head.dereference()
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elif head.type != list_head.get_type():
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raise TypeError("Must be struct list_head not {}"
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.format(head.type))
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if head['next'] == 0:
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gdb.write("list_for_each: Uninitialized list '{}' treated as empty\n"
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.format(head.address))
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return
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node = head['next'].dereference()
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while node.address != head.address:
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yield node.address
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node = node['next'].dereference()
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def list_for_each_entry(head, gdbtype, member):
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for node in list_for_each(head):
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yield utils.container_of(node, gdbtype, member)
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def hlist_for_each(head):
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if head.type == hlist_head.get_type().pointer():
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head = head.dereference()
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elif head.type != hlist_head.get_type():
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raise TypeError("Must be struct hlist_head not {}"
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.format(head.type))
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node = head['first'].dereference()
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while node.address:
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yield node.address
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node = node['next'].dereference()
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def hlist_for_each_entry(head, gdbtype, member):
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for node in hlist_for_each(head):
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yield utils.container_of(node, gdbtype, member)
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def list_check(head):
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nb = 0
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if (head.type == list_head.get_type().pointer()):
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head = head.dereference()
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elif (head.type != list_head.get_type()):
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raise gdb.GdbError('argument must be of type (struct list_head [*])')
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c = head
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try:
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gdb.write("Starting with: {}\n".format(c))
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except gdb.MemoryError:
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gdb.write('head is not accessible\n')
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return
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while True:
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p = c['prev'].dereference()
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n = c['next'].dereference()
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try:
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if p['next'] != c.address:
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gdb.write('prev.next != current: '
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'current@{current_addr}={current} '
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'prev@{p_addr}={p}\n'.format(
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current_addr=c.address,
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current=c,
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p_addr=p.address,
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p=p,
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))
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return
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except gdb.MemoryError:
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gdb.write('prev is not accessible: '
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'current@{current_addr}={current}\n'.format(
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current_addr=c.address,
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current=c
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))
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return
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try:
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if n['prev'] != c.address:
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gdb.write('next.prev != current: '
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'current@{current_addr}={current} '
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'next@{n_addr}={n}\n'.format(
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current_addr=c.address,
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current=c,
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n_addr=n.address,
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n=n,
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))
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return
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except gdb.MemoryError:
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gdb.write('next is not accessible: '
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'current@{current_addr}={current}\n'.format(
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current_addr=c.address,
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current=c
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))
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return
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c = n
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nb += 1
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if c == head:
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gdb.write("list is consistent: {} node(s)\n".format(nb))
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return
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class LxListChk(gdb.Command):
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"""Verify a list consistency"""
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def __init__(self):
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super(LxListChk, self).__init__("lx-list-check", gdb.COMMAND_DATA,
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gdb.COMPLETE_EXPRESSION)
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def invoke(self, arg, from_tty):
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argv = gdb.string_to_argv(arg)
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if len(argv) != 1:
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raise gdb.GdbError("lx-list-check takes one argument")
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list_check(gdb.parse_and_eval(argv[0]))
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LxListChk()
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