Bug #21351: Ruby master segfaults when initializing `Zlib::GzipReader`

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.5.0dev (2025-05-13T14:16:58Z master bb180b87b4) +PRISM [arm64-darwin24]
• Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[st0012 (Stan Lo)]

Ruby Version

ruby 3.5.0dev (2025-05-13T14:16:58Z master bb180b87b4) +PRISM [arm64-darwin24]
last_commit=[Bug #21331] Prohibit modification during stlike loop

Steps to reproduce

$ ruby -e "require 'zlib'; Zlib::GzipReader.new('')"

C backtrace

/Users/hung-wulo/.rubies/ruby-master/bin/ruby(rb_vm_bugreport+0xb6c) [0x102571c30]
/Users/hung-wulo/.rubies/ruby-master/bin/ruby(rb_bug_for_fatal_signal+0x100) [0x1023a3ebc]
/Users/hung-wulo/.rubies/ruby-master/bin/ruby(sigsegv+0x84) [0x1024caae0]
/usr/lib/system/libsystem_platform.dylib(_sigtramp+0x38) [0x1998fb624]
/Users/hung-wulo/.gem/ruby/ruby-master/gems/zlib-3.2.1/lib/zlib.bundle(gzfile_new+0x30) [0x11d6d2efc]
/Users/hung-wulo/.rubies/ruby-master/bin/ruby(rb_class_alloc+0xac) [0x1024366e8]
/Users/hung-wulo/.rubies/ruby-master/bin/ruby(vm_exec_core+0x38f4) [0x102549ac4]
/Users/hung-wulo/.rubies/ruby-master/bin/ruby(rb_vm_exec+0x1b0) [0x102544e08]
/Users/hung-wulo/.rubies/ruby-master/bin/ruby(rb_ec_exec_node+0x8c) [0x1023aef64]
/Users/hung-wulo/.rubies/ruby-master/bin/ruby(ruby_run_node+0x40) [0x1023aee8c]
/Users/hung-wulo/.rubies/ruby-master/bin/ruby(main+0x68) [0x1022f0980]

Full report is in the attached file

[st0012 (Stan Lo)]

• Status changed from Open to Closed

[st0012 (Stan Lo)]

Closed because this doesn't happen in ruby 3.5.0dev (2025-05-19T17:34:29Z master a7ef9a44a6) +PRISM [arm64-darwin24] anymore.