Changeset 665 for trunk/kernel

Timestamp:

Oct 10, 2020, 5:21:36 PM (4 years ago)

Author:

alain

Message:

Fix a bug in the vmm_get_vseg() function:
When the local VSL is also the reference VSL,
the vmm_get_vseg() tried to take twice the same lock.

File:

• trunk/kernel/mm/vmm.c (modified) (3 diffs)

trunk/kernel/mm/vmm.c

@@ -2108 +2108 @@
     remote_queuelock_acquire( loc_lock_xp );
 
-    // try to get vseg from local VMM
+    // try to get vseg from local VSL
     loc_vseg = vmm_vseg_from_vaddr( XPTR( local_cxy, &process->vmm ) , vaddr );
 
@@ -2120 +2120 @@
         process_t * ref_ptr = GET_PTR( ref_xp );
 
-        // build extended pointer on reference VSL lock
-        ref_lock_xp = XPTR( ref_cxy , &ref_ptr->vmm.vsl_lock );
-     
-        // get reference VSL lock 
-        remote_queuelock_acquire( ref_lock_xp );
-
-        // try to get vseg from reference VMM
-        ref_vseg = vmm_vseg_from_vaddr( XPTR( ref_cxy , &ref_ptr->vmm ) , vaddr );
-
-        if( ref_vseg == NULL )  // vseg not found => return error
+        if( ref_cxy == local_cxy )    // local is ref => return error
         {
             printk("\n[ERROR] in %s : vaddr %x in process %x out of segment\n",
             __FUNCTION__, vaddr, process->pid );
 
-            // release reference VSL lock 
-            remote_queuelock_release( ref_lock_xp );
+            // release local VSL lock
+            remote_queuelock_release( loc_lock_xp );
 
             return -1;
         }
-        else                    // vseg found => try to update local VSL 
+        else                          // ref != local => access ref VSL                     
         {
-            // allocate a local vseg descriptor
-            loc_vseg = vseg_alloc();
-
-            if( loc_vseg == NULL )   // no memory => return error
+            // build extended pointer on reference VSL lock
+            ref_lock_xp = XPTR( ref_cxy , &ref_ptr->vmm.vsl_lock );
+     
+            // get reference VSL lock 
+            remote_queuelock_acquire( ref_lock_xp );
+
+            // try to get vseg from reference VSL
+            ref_vseg = vmm_vseg_from_vaddr( XPTR( ref_cxy , &ref_ptr->vmm ) , vaddr );
+
+            if( ref_vseg == NULL )  // vseg not found => return error
             {
-                printk("\n[ERROR] in %s : vaddr %x in process %x / no memory for local vseg\n",
+                // release both VSL locks 
+                remote_queuelock_release( loc_lock_xp );
+                remote_queuelock_release( ref_lock_xp );
+
+                printk("\n[ERROR] in %s : vaddr %x in process %x out of segment\n",
                 __FUNCTION__, vaddr, process->pid );
-
-                // release reference VSL & local VSL locks
-                remote_queuelock_release( ref_lock_xp );
-                remote_queuelock_release( loc_lock_xp );
 
                 return -1;
             }
-            else                     // update local VSL and return success
+            else                    // vseg found => try to update local VSL 
             {
-                // initialize local vseg
-                vseg_init_from_ref( loc_vseg , XPTR( ref_cxy , ref_vseg ) );
-
-                // register local vseg in local VSL
-                vmm_attach_vseg_to_vsl( &process->vmm , loc_vseg );
-
-                // release reference VSL & local VSL locks
-                remote_queuelock_release( ref_lock_xp );
-                remote_queuelock_release( loc_lock_xp );
-
-                *found_vseg = loc_vseg;
-                return 0;
+                // allocate a local vseg descriptor
+                loc_vseg = vseg_alloc();
+
+                if( loc_vseg == NULL )   // no memory => return error
+                {
+                    printk("\n[ERROR] in %s : vaddr %x in process %x / no memory\n",
+                    __FUNCTION__, vaddr, process->pid );
+
+                    // release both VSL locks
+                    remote_queuelock_release( ref_lock_xp );
+                    remote_queuelock_release( loc_lock_xp );
+
+                    return -1;
+                }
+                else                     // update local VSL and return success
+                {
+                    // initialize local vseg
+                    vseg_init_from_ref( loc_vseg , XPTR( ref_cxy , ref_vseg ) );
+
+                    // register local vseg in local VSL
+                    vmm_attach_vseg_to_vsl( &process->vmm , loc_vseg );
+
+                    // release both VSL locks
+                    remote_queuelock_release( ref_lock_xp );
+                    remote_queuelock_release( loc_lock_xp );
+
+                    *found_vseg = loc_vseg;
+                    return 0;
+                }
             }
         }
@@ -2174 +2188 @@
     else                        // vseg found in local VSL => return success
     {
-        // release local VSL lock 
+        // release local VSL lock
         remote_queuelock_release( loc_lock_xp );