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8274632: Possible pointer overflow in PretouchTask chunk claiming

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Reviewed-by: tschatzl, ayang
This commit is contained in:
Kim Barrett 2021-10-05 08:07:02 +00:00
parent 8f7a37c92f
commit a914ee7216
2 changed files with 7 additions and 10 deletions
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14
src/hotspot/share/gc/shared/pretouchTask.cpp
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@ -36,7 +36,6 @@ PretouchTask::PretouchTask(const char* task_name,
size_t chunk_size) :
AbstractGangTask(task_name),
_cur_addr(start_address),
_start_addr(start_address),
_end_addr(end_address),
_page_size(page_size),
_chunk_size(chunk_size) {
@ -52,14 +51,13 @@ size_t PretouchTask::chunk_size() {
void PretouchTask::work(uint worker_id) {
while (true) {
char* touch_addr = Atomic::fetch_and_add(&_cur_addr, _chunk_size);
if (touch_addr < _start_addr || touch_addr >= _end_addr) {
char* cur_start = Atomic::load(&_cur_addr);
char* cur_end = cur_start + MIN2(_chunk_size, pointer_delta(_end_addr, cur_start, 1));
if (cur_start >= cur_end) {
break;
}
char* end_addr = touch_addr + MIN2(_chunk_size, pointer_delta(_end_addr, touch_addr, sizeof(char)));
os::pretouch_memory(touch_addr, end_addr, _page_size);
} else if (cur_start == Atomic::cmpxchg(&_cur_addr, cur_start, cur_end)) {
os::pretouch_memory(cur_start, cur_end, _page_size);
} // Else attempt to claim chunk failed, so try again.
}
}

3
src/hotspot/share/gc/shared/pretouchTask.hpp
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2020, 2021, 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
@ -29,7 +29,6 @@
class PretouchTask : public AbstractGangTask {
char* volatile _cur_addr;
char* const _start_addr;
char* const _end_addr;
size_t _page_size;
size_t _chunk_size;