Mercurial > hg > openjdk > jdk8u > hotspot
changeset 9161:3bdc0b789595
8216486: Possibility of integer overflow in JfrThreadSampler::run()
Reviewed-by: rehn, sgehwolf
| author | ysuenaga |
|---|---|
| date | Fri, 11 Jan 2019 23:32:52 +0900 |
| parents | 6388d0d497f7 |
| children | 4937bafbb2f8 |
| files | src/share/vm/jfr/periodic/sampling/jfrThreadSampler.cpp |
| diffstat | 1 files changed, 12 insertions(+), 3 deletions(-) [+] |
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--- a/src/share/vm/jfr/periodic/sampling/jfrThreadSampler.cpp Thu Dec 13 14:36:54 2018 +0100 +++ b/src/share/vm/jfr/periodic/sampling/jfrThreadSampler.cpp Fri Jan 11 23:32:52 2019 +0900 @@ -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 @@ -499,8 +499,17 @@ 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);