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8216486: Possibility of integer overflow in JfrThreadSampler::run()

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Reviewed-by: rehn, sgehwolf
This commit is contained in:
Yasumasa Suenaga 2019-01-11 23:32:52 +09:00
parent 83c8720879
commit 608258ffd1
1 changed files with 12 additions and 3 deletions
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15
src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2019, 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
@ -467,8 +467,17 @@ void JfrThreadSampler::run() {
jlong now_ms = get_monotonic_ms();
jlong next_j = java_interval + last_java_ms - now_ms;
jlong next_n = native_interval + last_native_ms - now_ms;
/*
* Let I be java_interval or native_interval.
* Let L be last_java_ms or last_native_ms.
* Let N be now_ms.
*
* Interval, I, might be max_jlong so the addition
* could potentially overflow without parenthesis (UB). Also note that
* L - N < 0. Avoid UB, by adding parenthesis.
*/
jlong next_j = java_interval + (last_java_ms - now_ms);
jlong next_n = native_interval + (last_native_ms - now_ms);
jlong sleep_to_next = MIN2<jlong>(next_j, next_n);