Changeset 46bbcaf for libcfa/src/concurrency

Timestamp:

Jan 20, 2022, 11:14:18 AM (2 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, ast-experimental, enum, forall-pointer-decay, master, pthread-emulation, qualifiedEnum

Children:

753fb978

Parents:

1e8b4b49

Message:

Fix race condition in verify

Location:

libcfa/src/concurrency

Files:

• kernel_private.hfa (modified) (1 diff)
• ready_queue.cfa (modified) (2 diffs)

libcfa/src/concurrency/kernel_private.hfa

@@ -219 +219 @@
 
         // Step 2 : acquire our local lock
+        /*paranoid*/ verify(!kernelTLS().sched_lock);
         __atomic_acquire( &kernelTLS().sched_lock );
         /*paranoid*/ verify(kernelTLS().sched_lock);

libcfa/src/concurrency/ready_queue.cfa

@@ -201 +201 @@
 uint_fast32_t ready_mutate_lock( void ) with(*__scheduler_lock) {
         /* paranoid */ verify( ! __preemption_enabled() );
-        /* paranoid */ verify( ! kernelTLS().sched_lock );
 
         // Step 1 : lock global lock
@@ -207 +206 @@
         //   to simply lock their own lock and enter.
         __atomic_acquire( &write_lock );
+
+        // Make sure we won't deadlock ourself
+        // Checking before acquiring the writer lock isn't safe
+        // because someone else could have locked us.
+        /* paranoid */ verify( ! kernelTLS().sched_lock );
 
         // Step 2 : lock per-proc lock