diff options
Diffstat (limited to 'library')
| -rw-r--r-- | library/std/src/sys/itron/thread.rs | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/library/std/src/sys/itron/thread.rs b/library/std/src/sys/itron/thread.rs index 68eebef1b20..535703be33f 100644 --- a/library/std/src/sys/itron/thread.rs +++ b/library/std/src/sys/itron/thread.rs @@ -151,6 +151,9 @@ impl Thread { // Since the parent might drop `*inner` and terminate us as // soon as it sees `JOIN_FINALIZE`, the release ordering // must be used in the above `swap` call. + // + // To make the task referred to by `parent_tid` visible, we + // must use the acquire ordering in the above `swap` call. // [JOINING → JOIN_FINALIZE] // Wake up the parent task. @@ -218,11 +221,15 @@ impl Thread { let current_task = current_task as usize; - match inner.lifecycle.swap(current_task, Ordering::Acquire) { + match inner.lifecycle.swap(current_task, Ordering::AcqRel) { LIFECYCLE_INIT => { // [INIT → JOINING] // The child task will transition the state to `JOIN_FINALIZE` // and wake us up. + // + // To make the task referred to by `current_task` visible from + // the child task's point of view, we must use the release + // ordering in the above `swap` call. loop { expect_success_aborting(unsafe { abi::slp_tsk() }, &"slp_tsk"); // To synchronize with the child task's memory accesses to |