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
42 BEGIN
43 {
44 check["futex_mtx"] = 0;
45 }
46
47 linuxulator*:locks:futex_mtx:locked
48 /check[probefunc] > 0/
49 {
50 printf("ERROR: recursive lock of %s (%p),", probefunc, arg0);
51 printf(" or missing SDT probe in kernel. Stack trace follows:");
52 stack();
53 }
54
55 linuxulator*:locks:futex_mtx:locked
56 {
57 ++check[probefunc];
58 @stats[probefunc] = count();
59
60 ts[probefunc] = timestamp;
61 spec[probefunc] = speculation();
62 }
63
64 linuxulator*:locks:futex_mtx:unlock
65 /check[probefunc] == 0/
66 {
67 printf("ERROR: unlock attempt of unlocked %s (%p),", probefunc, arg0);
68 printf(" missing SDT probe in kernel, or dtrace program started");
69 printf(" while the %s was already held (race condition).", probefunc);
70 printf(" Stack trace follows:");
71 stack();
72 }
73
74 linuxulator*:locks:futex_mtx:unlock
75 {
76 discard(spec[probefunc]);
77 spec[probefunc] = 0;
78 --check[probefunc];
79 }
80
81 /* Timeout handling */
82
83 tick-10s
84 /spec["futex_mtx"] != 0 && timestamp - ts["futex_mtx"] >= 9999999000/
85 {
86 commit(spec["futex_mtx"]);
87 spec["futex_mtx"] = 0;
88 }
89
90
91 /* Statistics */
92
93 END
94 {
95 printf("Number of locks per type:");
96 printa(@stats);
97 }
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