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 }
98