From 044fa35bf8ab277d90e12559f4de78e73a404033 Mon Sep 17 00:00:00 2001 From: Brian Anderson Date: Thu, 1 Aug 2013 21:14:43 -0700 Subject: [PATCH] rt: Fix a corner-case in unwinding that leads to stack overflow In some scenarios upcall_rust_stack_limit fails to record the stack limit, leaving it 0, and allowing subsequent Rust code to run into the red zone. --- src/rt/rust_task.cpp | 11 +++++++++++ src/test/run-pass/unwind-resource.rs | 3 ++- 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/src/rt/rust_task.cpp b/src/rt/rust_task.cpp index 72979d67eefc8..2f6b8acb0725c 100644 --- a/src/rt/rust_task.cpp +++ b/src/rt/rust_task.cpp @@ -609,10 +609,21 @@ when unwinding through __morestack). void rust_task::reset_stack_limit() { uintptr_t sp = get_sp(); + bool reseted = false; while (!sp_in_stk_seg(sp, stk)) { + reseted = true; prev_stack(); assert(stk != NULL && "Failed to find the current stack"); } + + // Each call to prev_stack will record the stack limit. If we *didn't* + // call prev_stack then we still need to record it now to catch a corner case: + // the throw to initiate unwinding starts on the C stack while sp limit is 0. + // If we don't set the limit here then the rust code run subsequently will + // will veer into the red zone. Lame! + if (!reseted) { + record_stack_limit(); + } } void diff --git a/src/test/run-pass/unwind-resource.rs b/src/test/run-pass/unwind-resource.rs index a36be079b4343..bde90e3726ed3 100644 --- a/src/test/run-pass/unwind-resource.rs +++ b/src/test/run-pass/unwind-resource.rs @@ -8,7 +8,8 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. -// xfail-test +// xfail-fast + extern mod extra; use std::comm::*;