Fix double-free crash under Perl ithreads#198
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When Perl ithreads clone an interpreter, blessed IV references (like our rsaData* pointers) are copied as raw integers. Both parent and child threads then call DESTROY on the same EVP_PKEY, causing a double-free. CLONE_SKIP makes cloned objects undef in child threads instead. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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What
Adds
CLONE_SKIPto prevent Crypt::OpenSSL::RSA objects from causingdouble-free crashes when Perl ithreads clone the interpreter.
Why
When
threads->create()clones the interpreter, blessed IV referencesare copied as raw integer values. Both parent and child threads end up
with the same
rsaData*pointer. When each thread'sDESTROYfires,the same
EVP_PKEYis freed twice — segfault or heap corruption.This is the standard failure mode for XS modules holding C pointers
under ithreads. The static buffer fix in PR #136 addressed one aspect
of thread safety, but the object lifecycle issue remained.
How
CLONE_SKIP { 1 }tells Perl to undef objects of this class in childthreads rather than shallow-copying them. Child threads must create
their own key objects — a safer semantic than silent memory corruption.
Testing
t/threads.tverifiesCLONE_SKIPis defined and that childthreads can independently generate keys without affecting the parent.
🤖 Generated with Claude Code
Quality Report
Changes: 2 files changed, 52 insertions(+)
Code scan: clean
Tests: passed (OK)
Branch hygiene: clean
Generated by Kōan post-mission quality pipeline