RFR: 8368124: Show useful thread names in ASAN reports [v7]

[Matthias Baesken]

On Thu, 25 Sep 2025 05:59:59 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> On Linux, ASAN only shows some internal thread designation on reports, e.g. `T49`, which is useless.
>> 
>> This patch adds the ability to see the real internal JVM thread names or user-supplied Java thread names in ASAN. This makes it possible to correlate ASAN reports with hs-err file reports (if ASAN is run with `halt_on_error=0` to give us a chance to get an hs-err file) or with a thread dump done beforehand.
>> 
>> Note that it can only show up to 15 characters, though. Therefore, the patch tries to be smart about names that end in digits: such numbers are preserved such that the truncation happens in the middle of the name, e.g.:
>> 
>> `"MyAllocationWorkerThread#4411"` -> `"MyAllocat..4411"`
>> 
>> This latter improvement now also applies to thread names in gdb, since they are subject to the same limitation.
>> 
>> For a detailed analysis of why the old version, using libpthread's `pthread_setname_np`, is not sufficient for thread names in ASAN, please see the issue description.
>> 
>> -----
>> 
>> Some examples from ASAN report: 
>> 
>> Before:
>> 
>> WRITE of size 8 at 0x7b749d2d9190 thread T49
>> 
>> 
>> Now:
>> 
>> WRITE of size 8 at 0x7bfc2f0d8380 thread T49 (MyThread#0)
>> 
>> 
>> 
>> ==593899==ERROR: AddressSanitizer: attempting free .. in thread T76 (MyAllocati..29)
>
> Thomas Stuefe has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - reorder includes
>  - remove redundant pthread_setname call

Tested it on our CI runs; the thread names look good now except for the JLI thread we seem to have no 'good' name just
'Thread T1 created by T0 here' ... but that's what it is right now. The others show the Java/JVM thread names .

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PR Comment: https://git.openjdk.org/jdk/pull/27395#issuecomment-3332515963