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8254189: Improve comments for StackOverFlow and fix in_xxx() functions
Reviewed-by: dholmes, gziemski
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tstuefe committed Oct 29, 2020
1 parent caec8d2 commit 4031cb41905a7b8675d102a708704da3e29d6535
Showing with 102 additions and 3 deletions.
  1. +11 −3 src/hotspot/share/runtime/stackOverflow.hpp
  2. +91 −0 test/hotspot/gtest/runtime/test_stackoverflow.cpp
@@ -137,12 +137,15 @@ class StackOverflow {
return _stack_red_zone_size;
}

// Returns base of red zone (one-beyond the highest red zone address, so
// itself outside red zone and the highest address of the yellow zone).
address stack_red_zone_base() const {
return (address)(stack_end() + stack_red_zone_size());
}

// Returns true if address points into the red zone.
bool in_stack_red_zone(address a) const {
return a <= stack_red_zone_base() && a >= stack_end();
return a < stack_red_zone_base() && a >= stack_end();
}

static size_t stack_yellow_zone_size() {
@@ -155,20 +158,25 @@ class StackOverflow {
return _stack_reserved_zone_size;
}

// Returns base of the reserved zone (one-beyond the highest reserved zone address).
address stack_reserved_zone_base() const {
return (address)(stack_end() +
(stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
}

// Returns true if address points into the reserved zone.
bool in_stack_reserved_zone(address a) const {
return (a <= stack_reserved_zone_base()) &&
return (a < stack_reserved_zone_base()) &&
(a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
}

static size_t stack_yellow_reserved_zone_size() {
return _stack_yellow_zone_size + _stack_reserved_zone_size;
}

// Returns true if a points into either yellow or reserved zone.
bool in_stack_yellow_reserved_zone(address a) const {
return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
return (a < stack_reserved_zone_base()) && (a >= stack_red_zone_base());
}

// Size of red + yellow + reserved zones.
@@ -0,0 +1,91 @@
/*
* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/

#include "precompiled.hpp"
#include "runtime/os.hpp"
#include "runtime/globals.hpp"
#include "runtime/stackOverflow.hpp"
#include "utilities/align.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/ostream.hpp"
#include "unittest.hpp"


TEST_VM(StackOverflow, basics) {
StackOverflow so;

// Make up a stack range. No need to allocate anything. Size has to be large enough
// to fit sum of all zones into them.
address base = (address) 0x40000000;
const size_t size = os::vm_page_size() * 100;
address end = base - size;
so.initialize(base, end);

// Walking down the "stack" check for consistency of the three "in_stack_xxx" functions
enum { normal_stack, reserved_or_yellow_zone, red_zone } where = normal_stack;
for (address p = base - 1; p >= end; p -= os::vm_page_size()) {
// tty->print_cr(PTR_FORMAT " %d %d %d", p2i(p),
// (int)so.in_stack_reserved_zone(p),
// (int)so.in_stack_yellow_reserved_zone(p),
// (int)so.in_stack_red_zone(p));
switch (where) {
case normal_stack:
ASSERT_FALSE(so.in_stack_red_zone(p));
if (so.in_stack_yellow_reserved_zone(p)) {
if (StackReservedPages > 0) {
ASSERT_TRUE(so.in_stack_reserved_zone(p));
} else {
ASSERT_FALSE(so.in_stack_reserved_zone(p));
}
where = reserved_or_yellow_zone;
} else {
ASSERT_FALSE(so.in_stack_reserved_zone((p)));
}
break;
case reserved_or_yellow_zone:
if (so.in_stack_red_zone(p)) {
ASSERT_FALSE(so.in_stack_yellow_reserved_zone(p));
where = red_zone;
} else {
ASSERT_TRUE(so.in_stack_yellow_reserved_zone(p));
}
break;
case red_zone:
ASSERT_TRUE(so.in_stack_red_zone(p));
ASSERT_FALSE(so.in_stack_yellow_reserved_zone(p));
ASSERT_FALSE(so.in_stack_reserved_zone((p)));
break;
}
}
ASSERT_EQ(where, red_zone);

// Check bases.
ASSERT_FALSE(so.in_stack_red_zone(so.stack_red_zone_base()));
ASSERT_TRUE(so.in_stack_red_zone(so.stack_red_zone_base() - 1));
ASSERT_TRUE(so.in_stack_yellow_reserved_zone(so.stack_red_zone_base()));
ASSERT_FALSE(so.in_stack_reserved_zone(so.stack_reserved_zone_base()));
if (so.stack_reserved_zone_size() > 0) {
ASSERT_TRUE(so.in_stack_reserved_zone(so.stack_reserved_zone_base() - 1));
}
}

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