use after ‘free’ of ‘*first.2_7->m_next.m_next’ [CWE-416] [-Wanalyzer-use-after-free]
38 first->m_next->m_next->m_next->m_next = NULL; /* { dg-warning "-Wanalyzer-use-after-free" } */
~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
test
test: events 1-2
28 test ()
^~~~
|
(1) entry to ‘test’
29 {
30 if (!append_value (42))
~~~~~~~~~~~~~~~~~
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(2) calling ‘append_value’ from ‘test’
append_value
append_value: events 3-7
12 append_value (int value)
^~~~~~~~~~~~
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(3) entry to ‘append_value’
13 {
14 struct node *n = __builtin_malloc (sizeof (struct node));
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
(4) allocated here
15 if (!n)
~
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(5) assuming ‘n’ is non-NULL
(6) following ‘false’ branch (when ‘n’ is non-NULL)... ─>─┐
│
│
┌───────────────────────────────────────────────────────────────┘
16│ return 0;
17│ n->m_val = value;
│ ~~~~~~~~~~~~~~~~
│ |
└──────────>(7) ...to here
test: event 8
30 if (!append_value (42))
^~~~~~~~~~~~~~~~~
|
(8) returning to ‘test’ from ‘append_value’
test: events 9-11
30 if (!append_value (42))
^
|
(9) following ‘false’ branch... ─>─┐
│
│
┌────────────────────────────────────────┘
31│ return;
32│ if (!append_value (1066))
│ ~~~~~~~~~~~~~~~~~~~
│ |
└──────>(10) ...to here
(11) calling ‘append_value’ from ‘test’
append_value
append_value: events 12-14
12 append_value (int value)
^~~~~~~~~~~~
|
(12) entry to ‘append_value’
[...]
15 if (!n)
~
|
(13) following ‘false’ branch (when ‘n’ is non-NULL)... ─>─┐
│
│
┌────────────────────────────────────────────────────────────────┘
16│ return 0;
17│ n->m_val = value;
│ ~~~~~~~~~~~~~~~~
│ |
└──────────>(14) ...to here
test: event 15
32 if (!append_value (1066))
^~~~~~~~~~~~~~~~~~~
|
(15) returning to ‘test’ from ‘append_value’
test: events 16-18
32 if (!append_value (1066))
^
|
(16) following ‘false’ branch... ─>─┐
│
│
┌─────────────────────────────────────────┘
33│ return;
34│ if (!append_value (1776))
│ ~~~~~~~~~~~~~~~~~~~
│ |
└──────>(17) ...to here
(18) calling ‘append_value’ from ‘test’
append_value
append_value: events 19-21
12 append_value (int value)
^~~~~~~~~~~~
|
(19) entry to ‘append_value’
[...]
15 if (!n)
~
|
(20) following ‘false’ branch (when ‘n’ is non-NULL)... ─>─┐
│
│
┌────────────────────────────────────────────────────────────────┘
16│ return 0;
17│ n->m_val = value;
│ ~~~~~~~~~~~~~~~~
│ |
└──────────>(21) ...to here
test: event 22
34 if (!append_value (1776))
^~~~~~~~~~~~~~~~~~~
|
(22) returning to ‘test’ from ‘append_value’
test: events 23-24
34 if (!append_value (1776))
^
|
(23) following ‘false’ branch... ─>─┐
│
[...]
│
┌─────────────────────────────────────────┘
37│ __builtin_free (first->m_next->m_next);
│ ~~
│ |
└──────────────────────>(24) ...to here
test: events 25-26
37 __builtin_free (first->m_next->m_next);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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(25) freed here
38 first->m_next->m_next->m_next->m_next = NULL; /* { dg-warning "-Wanalyzer-use-after-free" } */
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
(26) ⚠️ use after ‘free’ of ‘*first.2_7->m_next.m_next’; freed at (25)