Python/perf_jit_trampoline.c: Header.reserved field uninitialized

[stratakis]

Bug report

Bug description:

https://github.com/python/cpython/blame/bef63d2fb81ae28760040157ea589541bed47d02/Python/perf_jit_trampoline.c#L183

The field is never initialized and it may contain stack garbage which can pollute the jitdump files. This field is reserved by Perf for future use so I haven't seen any issues with that but if that changes in the future it might pose problems, plus the files could differ each time even if they are identical.

CPython versions tested on:

3.15, CPython main branch, 3.14, 3.13

Operating systems tested on:

Linux

Linked PRs

• gh-142779: Initialize reserved field for proper padding #142780