Bug #21266: YJIT GC safety crash with proc objects as block argument

• Status: Open
• Assignee: yjit
• Target version: -
• Backport: 3.2: DONTNEED, 3.3: REQUIRED, 3.4: REQUIRED

[alanwu (Alan Wu)]

# Run with --yjit-call-threshold=1
def foo(args) = bar(*args, &proc { _1 })
def bar(_, _, _, _, *rest) = yield rest

GC.stress = true
foo([1,2,3,4])
foo([1,2,3,4])

The proc in these calls get collected on the yield to the GC to allocate the rest parameter arary.

../vm_core.h:1668: Assertion Failed: vm_block_handler_type:rb_obj_is_proc(block_handler)

Or in release builds:

../test.rb:1: [BUG] Segmentation fault at 0x0000000000000020
ruby 3.3.6 (2024-11-05 revision 75015d4c1f) +YJIT [arm64-darwin24]

-- C level backtrace information -------------------------------------------
/Users/alan/.rubies/ruby-3.3.6/bin/ruby(rb_vm_bugreport+0xb4c) [0x104595590]
/Users/alan/.rubies/ruby-3.3.6/bin/ruby(rb_bug_for_fatal_signal+0x100) [0x1043d6120]
/Users/alan/.rubies/ruby-3.3.6/bin/ruby(sig_do_nothing+0x0) [0x1044fc4b0]
/usr/lib/system/libsystem_platform.dylib(_sigtramp+0x38) [0x187572de4]
/Users/alan/.rubies/ruby-3.3.6/bin/ruby(rb_vm_invokeblock+0x144) [0x10456b004]