Author: pfg
Date: Tue Jul 1 23:37:24 2014
New Revision: 268130
URL: http://svnweb.freebsd.org/changeset/base/268130
Log:
Merge from OpenSolaris (15-Sep-2008):
6735480 race between probe enabling and provider registration
MFC after: 1 week
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c Tue Jul
1 22:46:39 2014 (r268129)
+++ head/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c Tue Jul
1 23:37:24 2014 (r268130)
@@ -27,8 +27,6 @@
* Copyright (c) 2012 by Delphix. All rights reserved.
*/
-#pragma ident "%Z%%M% %I% %E% SMI"
-
/*
* DTrace - Dynamic Tracing for Solaris
*
@@ -238,6 +236,7 @@ static dtrace_ecb_t *dtrace_ecb_create_c
static dtrace_genid_t dtrace_probegen; /* current probe generation */
static dtrace_helpers_t *dtrace_deferred_pid; /* deferred helper list */
static dtrace_enabling_t *dtrace_retained; /* list of retained enablings */
+static dtrace_genid_t dtrace_retained_gen; /* current retained enab gen */
static dtrace_dynvar_t dtrace_dynhash_sink; /* end of dynamic hash chains */
#if !defined(sun)
static struct mtx dtrace_unr_mtx;
@@ -12393,6 +12392,7 @@ dtrace_enabling_destroy(dtrace_enabling_
ASSERT(enab->dten_vstate->dtvs_state != NULL);
ASSERT(enab->dten_vstate->dtvs_state->dts_nretained > 0);
enab->dten_vstate->dtvs_state->dts_nretained--;
+ dtrace_retained_gen++;
}
if (enab->dten_prev == NULL) {
@@ -12435,6 +12435,7 @@ dtrace_enabling_retain(dtrace_enabling_t
return (ENOSPC);
state->dts_nretained++;
+ dtrace_retained_gen++;
if (dtrace_retained == NULL) {
dtrace_retained = enab;
@@ -12677,6 +12678,7 @@ dtrace_enabling_provide(dtrace_provider_
{
int i, all = 0;
dtrace_probedesc_t desc;
+ dtrace_genid_t gen;
ASSERT(MUTEX_HELD(&dtrace_lock));
ASSERT(MUTEX_HELD(&dtrace_provider_lock));
@@ -12687,15 +12689,25 @@ dtrace_enabling_provide(dtrace_provider_
}
do {
- dtrace_enabling_t *enab = dtrace_retained;
+ dtrace_enabling_t *enab;
void *parg = prv->dtpv_arg;
- for (; enab != NULL; enab = enab->dten_next) {
+retry:
+ gen = dtrace_retained_gen;
+ for (enab = dtrace_retained; enab != NULL;
+ enab = enab->dten_next) {
for (i = 0; i < enab->dten_ndesc; i++) {
desc = enab->dten_desc[i]->dted_probe;
mutex_exit(&dtrace_lock);
prv->dtpv_pops.dtps_provide(parg, &desc);
mutex_enter(&dtrace_lock);
+ /*
+ * Process the retained enablings again if
+ * they have changed while we weren't holding
+ * dtrace_lock.
+ */
+ if (gen != dtrace_retained_gen)
+ goto retry;
}
}
} while (all && (prv = prv->dtpv_next) != NULL);
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