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std: don't leak the thread closure if destroying the thread attributes fails

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This commit is contained in:
joboet 2025-10-23 14:25:31 +02:00
parent 469357eb48
commit a7f08dec43
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GPG key ID: 704E0149B0194B3C
1 changed files with 13 additions and 15 deletions
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28
library/std/src/sys/thread/unix.rs
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@ -7,7 +7,7 @@
target_os = "aix",
)))]
use crate::ffi::CStr;
use crate::mem::{self, ManuallyDrop};
use crate::mem::{self, DropGuard, ManuallyDrop};
use crate::num::NonZero;
#[cfg(all(target_os = "linux", target_env = "gnu"))]
use crate::sys::weak::dlsym;
@ -52,10 +52,13 @@ impl Thread {
name: Option<&str>,
f: Box<dyn FnOnce()>,
) -> io::Result<Thread> {
let data = Box::into_raw(Box::new(ThreadData { name: name.map(Box::from), f }));
let mut native: libc::pthread_t = mem::zeroed();
let data = Box::new(ThreadData { name: name.map(Box::from), f });
let mut attr: mem::MaybeUninit<libc::pthread_attr_t> = mem::MaybeUninit::uninit();
assert_eq!(libc::pthread_attr_init(attr.as_mut_ptr()), 0);
let mut attr = DropGuard::new(&mut attr, |attr| {
assert_eq!(libc::pthread_attr_destroy(attr.as_mut_ptr()), 0)
});
#[cfg(any(target_os = "espidf", target_os = "nuttx"))]
if stack > 0 {
@ -90,8 +93,6 @@ impl Thread {
// on the stack size, in which case we can only gracefully return
// an error here.
if libc::pthread_attr_setstacksize(attr.as_mut_ptr(), stack_size) != 0 {
assert_eq!(libc::pthread_attr_destroy(attr.as_mut_ptr()), 0);
drop(Box::from_raw(data));
return Err(io::const_error!(
io::ErrorKind::InvalidInput,
"invalid stack size"
@ -101,19 +102,16 @@ impl Thread {
};
}
let data = Box::into_raw(data);
let mut native: libc::pthread_t = mem::zeroed();
let ret = libc::pthread_create(&mut native, attr.as_ptr(), thread_start, data as *mut _);
// Note: if the thread creation fails and this assert fails, then p will
// be leaked. However, an alternative design could cause double-free
// which is clearly worse.
assert_eq!(libc::pthread_attr_destroy(attr.as_mut_ptr()), 0);
return if ret != 0 {
// The thread failed to start and as a result p was not consumed. Therefore, it is
// safe to reconstruct the box so that it gets deallocated.
return if ret == 0 {
Ok(Thread { id: native })
} else {
// The thread failed to start and as a result `data` was not consumed.
// Therefore, it is safe to reconstruct the box so that it gets deallocated.
drop(Box::from_raw(data));
Err(io::Error::from_raw_os_error(ret))
} else {
Ok(Thread { id: native })
};
extern "C" fn thread_start(data: *mut libc::c_void) -> *mut libc::c_void {