1#!/usr/sbin/dtrace -qs
2
3/*-
4 * Copyright (c) 2008-2012 Alexander Leidinger <netchild@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer
12 *    in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31/**
32 * Check if the internal locks are correctly acquired/released:
33 *  - no recursive locking (mtx locks, write locks)
34 *  - no unlocking of already unlocked one
35 *
36 * Print stacktrace if a lock is longer locked than about 10sec or more.
37 */
38
39#pragma D option dynvarsize=32m
40#pragma D option specsize=32m
41
42BEGIN
43{
44	check["emul_lock"] = 0;
45	check["emul_shared_rlock"] = 0;
46	check["emul_shared_wlock"] = 0;
47	check["futex_mtx"] = 0;
48}
49
50linuxulator*:locks:emul_lock:locked,
51linuxulator*:locks:emul_shared_wlock:locked,
52linuxulator*:locks:futex_mtx:locked
53/check[probefunc] > 0/
54{
55	printf("ERROR: recursive lock of %s (%p),", probefunc, arg0);
56	printf("       or missing SDT probe in kernel. Stack trace follows:");
57	stack();
58}
59
60linuxulator*:locks:emul_lock:locked,
61linuxulator*:locks:emul_shared_rlock:locked,
62linuxulator*:locks:emul_shared_wlock:locked,
63linuxulator*:locks:futex_mtx:locked
64{
65	++check[probefunc];
66	@stats[probefunc] = count();
67
68	ts[probefunc] = timestamp;
69	spec[probefunc] = speculation();
70}
71
72linuxulator*:locks:emul_lock:unlock,
73linuxulator*:locks:emul_shared_rlock:unlock,
74linuxulator*:locks:emul_shared_wlock:unlock,
75linuxulator*:locks:futex_mtx:unlock
76/check[probefunc] == 0/
77{
78	printf("ERROR: unlock attemt of unlocked %s (%p),", probefunc, arg0);
79	printf("       missing SDT probe in kernel, or dtrace program started");
80	printf("       while the %s was already held (race condition).", probefunc);
81	printf("       Stack trace follows:");
82	stack();
83}
84
85linuxulator*:locks:emul_lock:unlock,
86linuxulator*:locks:emul_shared_rlock:unlock,
87linuxulator*:locks:emul_shared_wlock:unlock,
88linuxulator*:locks:futex_mtx:unlock
89{
90	discard(spec[probefunc]);
91	spec[probefunc] = 0;
92	--check[probefunc];
93}
94
95/* Timeout handling */
96
97tick-10s
98/spec["emul_lock"] != 0 && timestamp - ts["emul_lock"] >= 9999999000/
99{
100	commit(spec["emul_lock"]);
101	spec["emul_lock"] = 0;
102}
103
104tick-10s
105/spec["emul_shared_wlock"] != 0 && timestamp - ts["emul_shared_wlock"] >= 9999999000/
106{
107	commit(spec["emul_shared_wlock"]);
108	spec["emul_shared_wlock"] = 0;
109}
110
111tick-10s
112/spec["emul_shared_rlock"] != 0 && timestamp - ts["emul_shared_rlock"] >= 9999999000/
113{
114	commit(spec["emul_shared_rlock"]);
115	spec["emul_shared_rlock"] = 0;
116}
117
118tick-10s
119/spec["futex_mtx"] != 0 && timestamp - ts["futex_mtx"] >= 9999999000/
120{
121	commit(spec["futex_mtx"]);
122	spec["futex_mtx"] = 0;
123}
124
125
126/* Statistics */
127
128END
129{
130        printf("Number of locks per type:");
131	printa(@stats);
132}
133