RFR: 8301310: The SendRawSysexMessage test may cause a JVM crash [v4]

[Sergey Bylokhov]

On Thu, 9 Nov 2023 04:13:21 GMT, Alec Su <duke at openjdk.org> wrote:

>> The bug on Windows doesn't generate any error messages. During the testcase run, every "Open MIDI port" message should be followed by an "All SysexMessage sent" message. Alternatively, you can check `%ERRORLEVEL%` to determine if there's an error when JVM exits.
>> 
>> On Linux, there are no software MIDI devices provided by default. To reproduce this bug on Linux, you need to connect a real MIDI device to Linux or create a virtual MIDI device by running the command `sudo modprobe snd_virmidi midi_devs=1`.
>> 
>> The bug occurred because a pointer was increased on Line 137, then it attempted to release the modified pointer on Line 143.
>> 
>> https://github.com/openjdk/jdk/blob/e9d19d0fffc47119d0d4f756833ec87cd0a6331e/src/java.desktop/share/native/libjsound/MidiOutDevice.c#L128-L144
>> 
>> To fix this, I added a variable `msg` to store the modified pointer to prevent `data` pointer being modified.
>
> Alec Su has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix an error

Marked as reviewed by serb (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/16477#pullrequestreview-1724147929