From 5edaa7eefd76d4996dcf85dfc1c1a3f737087257 Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Thu, 12 Mar 2020 11:39:30 -0700 Subject: Fix abort-on-eprintln during process shutdown This commit fixes an issue where if `eprintln!` is used in a TLS destructor it can accidentally cause the process to abort. TLS destructors are executed after `main` returns on the main thread, and at this point we've also deinitialized global `Lazy` values like those which store the `Stderr` and `Stdout` internals. This means that despite handling TLS not being accessible in `eprintln!`, we will fail due to not being able to call `stderr()`. This means that we'll double-panic quickly because panicking also attempt to write to stderr. The fix here is to reimplement the global stderr handle to avoid the need for destruction. This avoids the need for `Lazy` as well as the hidden panic inside of the `stderr` function. Overall this should improve the robustness of printing errors and/or panics in weird situations, since the `stderr` accessor should be infallible in more situations. --- src/libstd/sys/wasm/mutex.rs | 4 ++-- src/libstd/sys/wasm/mutex_atomics.rs | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'src/libstd/sys/wasm') diff --git a/src/libstd/sys/wasm/mutex.rs b/src/libstd/sys/wasm/mutex.rs index 07238d08730..7aaf1b3a343 100644 --- a/src/libstd/sys/wasm/mutex.rs +++ b/src/libstd/sys/wasm/mutex.rs @@ -47,11 +47,11 @@ impl Mutex { pub struct ReentrantMutex {} impl ReentrantMutex { - pub unsafe fn uninitialized() -> ReentrantMutex { + pub const unsafe fn uninitialized() -> ReentrantMutex { ReentrantMutex {} } - pub unsafe fn init(&mut self) {} + pub unsafe fn init(&self) {} pub unsafe fn lock(&self) {} diff --git a/src/libstd/sys/wasm/mutex_atomics.rs b/src/libstd/sys/wasm/mutex_atomics.rs index 90c628a19c2..268a53bb564 100644 --- a/src/libstd/sys/wasm/mutex_atomics.rs +++ b/src/libstd/sys/wasm/mutex_atomics.rs @@ -80,11 +80,11 @@ unsafe impl Sync for ReentrantMutex {} // released when this recursion counter reaches 0. impl ReentrantMutex { - pub unsafe fn uninitialized() -> ReentrantMutex { + pub const unsafe fn uninitialized() -> ReentrantMutex { ReentrantMutex { owner: AtomicU32::new(0), recursions: UnsafeCell::new(0) } } - pub unsafe fn init(&mut self) { + pub unsafe fn init(&self) { // nothing to do... } -- cgit 1.4.1-3-g733a5