19e252baeb
- DTrace scripts to check for errors, performance, ... they serve mostly as examples of what you can do with the static probe;s with moderate load the scripts may be overwhelmed, excessive lock-tracing may influence program behavior (see the last design decission) Design decissions: - use "linuxulator" as the provider for the native bitsize; add the bitsize for the non-native emulation (e.g. "linuxuator32" on amd64) - Add probes only for locks which are acquired in one function and released in another function. Locks which are aquired and released in the same function should be easy to pair in the code, inter-function locking is more easy to verify in DTrace. - Probes for locks should be fired after locking and before releasing to prevent races (to provide data/function stability in DTrace, see the man-page of "dtrace -v ..." and the corresponding DTrace docs).
133 lines
3.8 KiB
D
133 lines
3.8 KiB
D
#!/usr/sbin/dtrace -qs
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/*-
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* Copyright (c) 2008-2012 Alexander Leidinger <netchild@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/**
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* Check if the internal locks are correctly acquired/released:
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* - no recursive locking (mtx locks, write locks)
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* - no unlocking of already unlocked one
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*
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* Print stacktrace if a lock is longer locked than about 10sec or more.
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*/
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#pragma D option dynvarsize=32m
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#pragma D option specsize=32m
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BEGIN
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{
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check["emul_lock"] = 0;
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check["emul_shared_rlock"] = 0;
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check["emul_shared_wlock"] = 0;
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check["futex_mtx"] = 0;
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}
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linuxulator*:locks:emul_lock:locked,
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linuxulator*:locks:emul_shared_wlock:locked,
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linuxulator*:locks:futex_mtx:locked
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/check[probefunc] > 0/
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{
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printf("ERROR: recursive lock of %s (%p),", probefunc, arg0);
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printf(" or missing SDT probe in kernel. Stack trace follows:");
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stack();
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}
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linuxulator*:locks:emul_lock:locked,
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linuxulator*:locks:emul_shared_rlock:locked,
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linuxulator*:locks:emul_shared_wlock:locked,
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linuxulator*:locks:futex_mtx:locked
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{
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++check[probefunc];
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@stats[probefunc] = count();
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ts[probefunc] = timestamp;
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spec[probefunc] = speculation();
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}
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linuxulator*:locks:emul_lock:unlock,
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linuxulator*:locks:emul_shared_rlock:unlock,
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linuxulator*:locks:emul_shared_wlock:unlock,
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linuxulator*:locks:futex_mtx:unlock
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/check[probefunc] == 0/
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{
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printf("ERROR: unlock attemt of unlocked %s (%p),", probefunc, arg0);
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printf(" missing SDT probe in kernel, or dtrace program started");
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printf(" while the %s was already held (race condition).", probefunc);
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printf(" Stack trace follows:");
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stack();
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}
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linuxulator*:locks:emul_lock:unlock,
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linuxulator*:locks:emul_shared_rlock:unlock,
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linuxulator*:locks:emul_shared_wlock:unlock,
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linuxulator*:locks:futex_mtx:unlock
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{
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discard(spec[probefunc]);
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spec[probefunc] = 0;
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--check[probefunc];
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}
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/* Timeout handling */
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tick-10s
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/spec["emul_lock"] != 0 && timestamp - ts["emul_lock"] >= 9999999000/
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{
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commit(spec["emul_lock"]);
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spec["emul_lock"] = 0;
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}
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tick-10s
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/spec["emul_shared_wlock"] != 0 && timestamp - ts["emul_shared_wlock"] >= 9999999000/
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{
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commit(spec["emul_shared_wlock"]);
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spec["emul_shared_wlock"] = 0;
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}
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tick-10s
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/spec["emul_shared_rlock"] != 0 && timestamp - ts["emul_shared_rlock"] >= 9999999000/
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{
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commit(spec["emul_shared_rlock"]);
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spec["emul_shared_rlock"] = 0;
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}
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tick-10s
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/spec["futex_mtx"] != 0 && timestamp - ts["futex_mtx"] >= 9999999000/
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{
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commit(spec["futex_mtx"]);
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spec["futex_mtx"] = 0;
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}
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/* Statistics */
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END
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{
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printf("Number of locks per type:");
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printa(@stats);
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}
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