7fc219a5ee
It is yet another psref leak detector that enables to tell where a leak occurs while a simpler version that is already committed just tells an occurrence of a leak. Investigating of psref leaks is hard because once a leak occurs a percpu list of psref that tracks references can be corrupted. A reference to a tracking object is memorized in the list via an intermediate object (struct psref) that is normally allocated on a stack of a thread. Thus, the intermediate object can be overwritten on a leak resulting in corruption of the list. The tracker makes a shadow entry to an intermediate object and stores some hints into it (currently it's a caller address of psref_acquire). We can detect a leak by checking the entries on certain points where any references should be released such as the return point of syscalls and the end of each softint handler. The feature is expensive and enabled only if the kernel is built with PSREF_DEBUG. Proposed on tech-kern
140 lines
3.9 KiB
C
140 lines
3.9 KiB
C
/* $NetBSD: subr_lwp_specificdata.c,v 1.4 2019/05/17 03:34:26 ozaki-r Exp $ */
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/*-
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* Copyright (c) 2006 The NetBSD Foundation, Inc.
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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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* 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#define _LWP_API_PRIVATE
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: subr_lwp_specificdata.c,v 1.4 2019/05/17 03:34:26 ozaki-r Exp $");
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#include <sys/param.h>
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#include <sys/lwp.h>
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#include <sys/specificdata.h>
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static specificdata_domain_t lwp_specificdata_domain;
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void
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lwpinit_specificdata(void)
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{
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lwp_specificdata_domain = specificdata_domain_create();
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KASSERT(lwp_specificdata_domain != NULL);
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}
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/*
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* lwp_specific_key_create --
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* Create a key for subsystem lwp-specific data.
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*/
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int
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lwp_specific_key_create(specificdata_key_t *keyp, specificdata_dtor_t dtor)
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{
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return (specificdata_key_create(lwp_specificdata_domain, keyp, dtor));
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}
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/*
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* lwp_specific_key_delete --
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* Delete a key for subsystem lwp-specific data.
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*/
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void
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lwp_specific_key_delete(specificdata_key_t key)
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{
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specificdata_key_delete(lwp_specificdata_domain, key);
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}
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/*
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* lwp_initspecific --
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* Initialize an LWP's specificdata container.
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*/
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void
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lwp_initspecific(struct lwp *l)
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{
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int error __diagused;
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error = specificdata_init(lwp_specificdata_domain, &l->l_specdataref);
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KASSERT(error == 0);
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}
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/*
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* lwp_finispecific --
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* Finalize an LWP's specificdata container.
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*/
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void
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lwp_finispecific(struct lwp *l)
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{
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specificdata_fini(lwp_specificdata_domain, &l->l_specdataref);
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}
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/*
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* lwp_getspecific --
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* Return lwp-specific data corresponding to the specified key.
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*
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* Note: LWP specific data is NOT INTERLOCKED. An LWP should access
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* only its OWN SPECIFIC DATA. If it is necessary to access another
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* LWP's specifc data, care must be taken to ensure that doing so
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* would not cause internal data structure inconsistency (i.e. caller
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* can guarantee that the target LWP is not inside an lwp_getspecific()
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* or lwp_setspecific() call).
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*/
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void *
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lwp_getspecific(specificdata_key_t key)
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{
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return (specificdata_getspecific_unlocked(lwp_specificdata_domain,
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&curlwp->l_specdataref, key));
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}
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void *
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_lwp_getspecific_by_lwp(struct lwp *l, specificdata_key_t key)
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{
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return (specificdata_getspecific_unlocked(lwp_specificdata_domain,
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&l->l_specdataref, key));
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}
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/*
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* lwp_setspecific --
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* Set lwp-specific data corresponding to the specified key.
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*/
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void
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lwp_setspecific(specificdata_key_t key, void *data)
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{
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specificdata_setspecific(lwp_specificdata_domain,
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&curlwp->l_specdataref, key, data);
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}
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void
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lwp_setspecific_by_lwp(struct lwp *l, specificdata_key_t key, void *data)
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{
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specificdata_setspecific(lwp_specificdata_domain,
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&l->l_specdataref, key, data);
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}
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