Skip to content

main: boxed-slot skipped-init read SIGSEGVs (#4926 regression, scope contexts) #11771

Description

@proggeramlug

crates/perry/tests/issue_4926_boxed_slot_skipped_init.rs::boxed_var_skipped_init_is_defined_behavior fails on main: the compiled fixture binary SIGSEGVs (exit 139). It reproduces on cab6d62 and on PR #11680's head. Main's CI skips the cargo-test-perry shards, which is why main shows it as green.

Crash site. gdb stops at vmovsd (%rax) in readSkipped$spec_i32, with rax = 0x7ffc000000000001 (TAG_UNDEFINED).

What happens. A captured let x now lives in a GC scope context (js_scope_alloc). When the read runs on a path where the let never executed (case 2: typeof x), it loads straight through the slot. The slot still holds its TAG_UNDEFINED initial value, so the read dereferences that value as a pointer.

Likely origin. #11710 (e6b897e, "GC scope contexts for captured bindings"). This is matched from the code, not bisected.

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions