From 9733463d2b141a166bfa2f55ec316066ab0f71b6 Mon Sep 17 00:00:00 2001 From: Steven Fackler Date: Sat, 23 Sep 2017 21:19:01 -0700 Subject: [PATCH 1/2] Fix capacity comparison in reserve You can otherwise end up in a situation where you don't actually resize but still call into handle_cap_increase which then corrupts head/tail. Closes #44800 --- src/liballoc/vec_deque.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/liballoc/vec_deque.rs b/src/liballoc/vec_deque.rs index 6836fbb7c4d..6d64e9e303f 100644 --- a/src/liballoc/vec_deque.rs +++ b/src/liballoc/vec_deque.rs @@ -558,7 +558,7 @@ impl VecDeque { .and_then(|needed_cap| needed_cap.checked_next_power_of_two()) .expect("capacity overflow"); - if new_cap > self.capacity() { + if new_cap > old_cap { self.buf.reserve_exact(used_cap, new_cap - used_cap); unsafe { self.handle_cap_increase(old_cap); From 81bac74c2ddc6c39f3628a36966f4a56a1282d02 Mon Sep 17 00:00:00 2001 From: Steven Fackler Date: Sun, 24 Sep 2017 10:56:08 -0700 Subject: [PATCH 2/2] Add a run-pass-valgrind test for vecdeque issue --- src/test/run-pass-valgrind/issue-44800.rs | 25 +++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 src/test/run-pass-valgrind/issue-44800.rs diff --git a/src/test/run-pass-valgrind/issue-44800.rs b/src/test/run-pass-valgrind/issue-44800.rs new file mode 100644 index 00000000000..cfde6f32f66 --- /dev/null +++ b/src/test/run-pass-valgrind/issue-44800.rs @@ -0,0 +1,25 @@ +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![feature(global_allocator, alloc_system, allocator_api)] +extern crate alloc_system; + +use std::collections::VecDeque; +use alloc_system::System; + +#[global_allocator] +static ALLOCATOR: System = System; + +fn main() { + let mut deque = VecDeque::with_capacity(32); + deque.push_front(0); + deque.reserve(31); + deque.push_back(0); +}