Changeset d896525 in mainline

Timestamp:

2005-06-09T13:35:13Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

18e0a6c

Parents:

a7a1063

Message:

Fix wrong locking order in scheduler.

File:

• src/proc/scheduler.c (modified) (2 diffs)

src/proc/scheduler.c

@@ -118 +118 @@
 
         cpu_priority_high();
-
-        for (i = 0; i<RQ_COUNT; i++) {
+        
+        i = 0;
+retry:
+        for (; i<RQ_COUNT; i++) {
                 r = &CPU->rq[i];
                 spinlock_lock(&r->lock);
@@ -130 +132 @@
                 }
         
-                atomic_dec(&nrdy);
-
-                spinlock_lock(&CPU->lock);
+                /* avoid deadlock with relink_rq */
+                if (!spinlock_trylock(&CPU->lock)) {
+                        /*
+                         * Unlock r and try again.
+                         */
+                        spinlock_unlock(&r->lock);
+                        goto retry;
+                }
                 CPU->nrdy--;
                 spinlock_unlock(&CPU->lock);
 
+                atomic_dec(&nrdy);
                 r->n--;