On Sun, 22 Jun 2025, Daisuke Fujimura via Cygwin wrote: > The reproduction procedure could be simplified. > > A segmentation fault (SIGSEGV) occurs when running a Ruby script using > Ruby 3.4.2 (test package) on Cygwin 3.6.3-1 (x86_64), where Thread.new > is used to require 'openssl' inside a thread. > > The crash path leads from OpenSSL’s OPENSSL_thread_stop() to > CRYPTO_THREAD_write_lock() and then pthread_rwlock_wrlock(), which > invokes pthread_testcancel(). At that point, a NULL pointer > dereference seems to occur, possibly during access to TLS data. > > Thread 8 "repro.rb:1" received signal SIGSEGV, Segmentation fault. > [Switching to Thread 7380.0x25e4] > 0x0000000000000000 in ?? () > (gdb) where > #0 0x0000000000000000 in ?? () > #1 0x00007ffe4ad2a0e4 in pthread_testcancel () at > /usr/src/debug/cygwin-3.6.3-1/winsup/cygwin/thread.cc:399 > #2 pthread_rwlock_wrlock (rwlock=0xa002a9010) at > /usr/src/debug/cygwin-3.6.3-1/winsup/cygwin/thread.cc:4352 > #3 0x00007ffe4ae0b0d4 in _sigfe () at sigfe.s:35 > #4 0x00000003ff54e3f9 in CRYPTO_THREAD_write_lock (lock=<optimized > out>) at crypto/threads_pthread.c:110 > #5 0x00000003ff541922 in init_thread_remove_handlers > (handsin=handsin@entry=0x0) at crypto/initthread.c:178 > #6 0x00000003ff541d43 in OPENSSL_thread_stop () at crypto/initthread.c:235 > #7 0x00000003ff53fdd3 in DllMain (hinstDLL=<optimized out>, > fdwReason=<optimized out>, lpvReserved=<optimized out>) > at crypto/dllmain.c:38 > #8 0x00007ffe8f2fd6ac in ?? () > #9 0x00007ffe8f38b590 in ?? () > #10 0x00007ffe8f38b590 in ?? () > #11 0x0000000000000000 in ?? ()
This should be fixed by test release openssl-3.0.16-2 (https://cygwin.com/pipermail/cygwin-announce/2025-May/012341.html). I don't know what the plan is for making that stable, or getting a patch upstream. -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
