Issue #19320 has been updated by naruse (Yui NARUSE). Backport changed from 2.7: DONTNEED, 3.0: REQUIRED, 3.1: REQUIRED, 3.2: REQUIRED to 2.7: DONTNEED, 3.0: REQUIRED, 3.1: REQUIRED, 3.2: DONE ruby_3_2 a20061cb1aa34b73bdbdfa7cba6cfc575a05ca38 merged revision(s) 72eb33066fa9e7dacb7470cd140b219abe37667e. ---------------------------------------- Bug #19320: Crash during compaction while traversing the stack https://bugs.ruby-lang.org/issues/19320#change-101448 * Author: peterzhu2118 (Peter Zhu) * Status: Closed * Priority: Normal * Backport: 2.7: DONTNEED, 3.0: REQUIRED, 3.1: REQUIRED, 3.2: DONE ---------------------------------------- Fix PR: https://github.com/ruby/ruby/pull/7081 Applying the following patch to test/erb/test_erb.rb and running that file will cause Ruby to crash on my machine (macOS 13.1 on M1 Pro): ```diff --- a/test/erb/test_erb.rb +++ b/test/erb/test_erb.rb @@ -7,6 +7,12 @@ class TestERB < Test::Unit::TestCase class MyError < RuntimeError ; end + def setup + GC.auto_compact = true + GC.stress = true + GC.verify_compaction_references(expand_heap: true, toward: :empty) + end + ``` It crashes with the following log: ``` /Users/peter/src/ruby/lib/erb/compiler.rb:276: [BUG] Segmentation fault at 0x00000001083a8690 ... -- C level backtrace information ------------------------------------------- ... /Users/peter/src/ruby/build/ruby(rb_vm_each_stack_value+0xa8) [0x104cc3a44] ../vm.c:2737 /Users/peter/src/ruby/build/ruby(rb_vm_each_stack_value+0xa8) [0x104cc3a44] ../vm.c:2737 /Users/peter/src/ruby/build/ruby(check_stack_for_moved+0x2c) [0x104b272a4] ../gc.c:5512 /Users/peter/src/ruby/build/ruby(gc_compact_finish) ../gc.c:5534 /Users/peter/src/ruby/build/ruby(gc_sweep_compact) ../gc.c:8653 /Users/peter/src/ruby/build/ruby(gc_sweep) ../gc.c:6196 /Users/peter/src/ruby/build/ruby(has_sweeping_pages+0x0) [0x104b19c54] ../gc.c:9568 /Users/peter/src/ruby/build/ruby(gc_rest) ../gc.c:9570 ``` This crash happens because it's reading the VALUE at sp. But since sp points to the top of the stack, it's reading the VALUE above the top of the stack, which is causing this segfault. I can repro this crash in Ruby 3.2.0, but looking at the code I think it can happen in Ruby 3.1 and 3.0 as well. -- https://bugs.ruby-lang.org/