Bug #19482: Fix crash when allocating classes with newobj hook

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONTNEED, 3.2: DONE

[peterzhu2118 (Peter Zhu)]

GitHub PR: https://github.com/ruby/ruby/pull/7464

We need to zero out the whole slot when running the newobj hook for a newly allocated class because the slot could be filled with garbage, which would cause a crash if a GC runs inside of the newobj hook.

For example, the following script crashes:

require "objspace"

GC.stress = true

ObjectSpace.trace_object_allocations {
  100.times do
    Class.new
  end
}

[peterzhu2118 (Peter Zhu)]

• Status changed from Open to Closed

Applied in changeset git|e1bd45624c85e8a80991bda20801f50967ac77a1.

---

Fix crash when allocating classes with newobj hook

We need to zero out the whole slot when running the newobj hook for a
newly allocated class because the slot could be filled with garbage,
which would cause a crash if a GC runs inside of the newobj hook.

For example, the following script crashes:

require "objspace"

GC.stress = true

ObjectSpace.trace_object_allocations {
  100.times do
    Class.new
  end
}

[Bug #19482]

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONTNEED, 3.2: REQUIRED to 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONTNEED, 3.2: DONE

ruby_3_2 141402d11c09fa641eebd8f4841f81e7bbf3518c merged revision(s) e1bd45624c85e8a80991bda20801f50967ac77a1.