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Catch panics in destruction of TLS values

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`destroy_value` is/can be called from C code (libc). Unwinding
from Rust to C code is undefined behavior, which is why unwinding
is caught here.
This commit is contained in:
Florian Bartels 2022-12-16 09:03:46 +01:00
parent d67000e44e
commit 04a6f22f79
No known key found for this signature in database
1 changed files with 14 additions and 7 deletions
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21
library/std/src/thread/local.rs
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@ -905,9 +905,8 @@ pub unsafe fn get(&self, init: impl FnOnce() -> T) -> Option<&'static T> {
pub mod fast {
use super::lazy::LazyKeyInner;
use crate::cell::Cell;
use crate::fmt;
use crate::mem;
use crate::sys::thread_local_dtor::register_dtor;
use crate::{fmt, mem, panic};
#[derive(Copy, Clone)]
enum DtorState {
@ -1028,10 +1027,15 @@ unsafe fn try_register_dtor(&self) -> bool {
// `Option<T>` to `None`, and `dtor_state` to `RunningOrHasRun`. This
// causes future calls to `get` to run `try_initialize_drop` again,
// which will now fail, and return `None`.
unsafe {
//
// Wrap the call in a catch to ensure unwinding is caught in the event
// a panic takes place in a destructor.
if let Err(_) = panic::catch_unwind(panic::AssertUnwindSafe(|| unsafe {
let value = (*ptr).inner.take();
(*ptr).dtor_state.set(DtorState::RunningOrHasRun);
drop(value);
})) {
rtabort!("thread local panicked on drop");
}
}
}
@ -1044,10 +1048,8 @@ unsafe fn try_register_dtor(&self) -> bool {
pub mod os {
use super::lazy::LazyKeyInner;
use crate::cell::Cell;
use crate::fmt;
use crate::marker;
use crate::ptr;
use crate::sys_common::thread_local_key::StaticKey as OsStaticKey;
use crate::{fmt, marker, panic, ptr};
/// Use a regular global static to store this key; the state provided will then be
/// thread-local.
@ -1137,12 +1139,17 @@ unsafe fn try_initialize(&'static self, init: impl FnOnce() -> T) -> Option<&'st
//
// Note that to prevent an infinite loop we reset it back to null right
// before we return from the destructor ourselves.
unsafe {
//
// Wrap the call in a catch to ensure unwinding is caught in the event
// a panic takes place in a destructor.
if let Err(_) = panic::catch_unwind(|| unsafe {
let ptr = Box::from_raw(ptr as *mut Value<T>);
let key = ptr.key;
key.os.set(ptr::invalid_mut(1));
drop(ptr);
key.os.set(ptr::null_mut());
}) {
rtabort!("thread local panicked on drop");
}
}
}