RFR: 8332699: ubsan: jfrEventSetting.inline.hpp:31:43: runtime error: index 163 out of bounds for type 'jfrNativeEventSetting [162]'

[Thomas Stuefe]

On Mon, 10 Jun 2024 12:30:59 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> When running hs :tier1 tests or jdk/jfr tests, with ubsan enabled (configure flag --enable-ubsan), in a lot of jfr related tests like
> compiler/intrinsics/klass/CastNullCheckDroppingsTest.jtr
> serviceability/jvmti/RedefineClasses/RedefineSharedClassJFR.jtr
> this oob error can be seen :
> 
> /jdk/src/hotspot/share/jfr/recorder/jfrEventSetting.inline.hpp:31:43: runtime error: index 163 out of bounds for type 'jfrNativeEventSetting [162]'
>     #0 0x7f6b75a8634b in JfrEventSetting::setting(JfrEventId) /jdk/src/hotspot/share/jfr/recorder/jfrEventSetting.inline.hpp:31
>     #1 0x7f6b75a8634b in JfrEventSetting::set_stacktrace(long, bool) /jdk/src/hotspot/share/jfr/recorder/jfrEventSetting.cpp:47
> 
> Looks like the array in generated code is too small.
> With
> `jfrNativeEventSetting bits[NUMBER_OF_EVENTS];`
> and
> 
> static const int NUMBER_OF_EVENTS = 162;
> static const int NUMBER_OF_RESERVED_EVENTS = 2;
> 
> 
> Access at index 163 cannot work.
> But it looks like there is always enough memory after the array so we do not crash and it was not noticed before.

About your fix, do you know why MetadataEvent and CheckPointEvent would not count toward the number of events? In other words, why NUMBER_OF_EVENTS is 162 if we have 164 events? Maybe the number of events is wrong? 

@egahlin ?

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PR Comment: https://git.openjdk.org/jdk/pull/19628#issuecomment-2161218498