small fixes and add locks

3 files changed, 9 insertions, 21 deletions

diff --git a/kernel/vm/pagefault.c b/kernel/vm/pagefault.c
index 39e5776..4be12cd 100644
--- a/kernel/vm/pagefault.c
+++ b/kernel/vm/pagefault.c
@@ -91,17 +91,12 @@ void handle_pagefault(uintptr_t vaddr, uintptr_t cause)
     }
 
     // Obtain the corresponding pframe from the vmarea's mobj
-    long forwrite = 0;
-    if (cause & FAULT_WRITE) 
-    {
-        forwrite = 1;
-    }
     pframe_t* pfp;
     mobj_lock(vma->vma_obj);
     long status = mobj_get_pframe(
         vma->vma_obj, 
         pn - vma->vma_start + vma->vma_off,
-        forwrite, 
+        (long) ((cause & FAULT_WRITE) ? 1 : 0),
         &pfp
     );
     mobj_unlock(vma->vma_obj);
diff --git a/kernel/vm/shadow.c b/kernel/vm/shadow.c
index 4166597..e0a8674 100644
--- a/kernel/vm/shadow.c
+++ b/kernel/vm/shadow.c
@@ -128,10 +128,10 @@ void shadow_collapse(mobj_t *o)
 
     dbg(DBG_PRINT, "shadow_collapse: refcount bottom: %d\n", so->bottom_mobj->mo_refcount);
 
-    while (shadowed->mo_type == MOBJ_SHADOW)
+    while (shadowed && shadowed->mo_type == MOBJ_SHADOW)
     {
-        mobj_shadow_t *so_shadowed = MOBJ_TO_SO(shadowed);
-        mobj_t *shadowed_shadowed = so_shadowed->shadowed;
+        // mobj_shadow_t *so_shadowed = MOBJ_TO_SO(shadowed);
+        mobj_t *shadowed_shadowed = MOBJ_TO_SO(shadowed)->shadowed;
 
         // if the refcount is not 1, then we can't collapse
         if (shadowed_shadowed->mo_refcount != 1)
@@ -157,19 +157,14 @@ void shadow_collapse(mobj_t *o)
                 pframe_release(&pf_shadow);
             }
         }
-        mobj_unlock(shadowed_shadowed);
-
-        if (shadowed_shadowed->mo_type != MOBJ_SHADOW)
-        {
-            // put the shadowed object
-            mobj_put(&shadowed);
-            break;
-        }
 
         // get the pointer to the shadowed object
         mobj_shadow_t *so_shadowed_shadowed = MOBJ_TO_SO(shadowed_shadowed);
         so->shadowed = shadowed_shadowed;
+
+        mobj_lock(so->shadowed);
         mobj_ref(so->shadowed);
+        mobj_unlock(so->shadowed);
 
         // put the shadowed object
         mobj_put(&shadowed);
diff --git a/kernel/vm/vmmap.c b/kernel/vm/vmmap.c
index 34dfaa5..ad95d33 100644
--- a/kernel/vm/vmmap.c
+++ b/kernel/vm/vmmap.c
@@ -201,7 +201,6 @@ ssize_t vmmap_find_range(vmmap_t *map, size_t npages, int dir)
             // if the range exists, return the start
             if (contig_page == npages)
             {
-                KASSERT(start_page >= ADDR_TO_PN(USER_MEM_LOW));
                 return start_page;
             }
         }
@@ -231,7 +230,6 @@ ssize_t vmmap_find_range(vmmap_t *map, size_t npages, int dir)
             // if there are n contiguous pages, return the current vfn
             if (contig == npages)
             {
-                KASSERT(vfn >= ADDR_TO_PN(USER_MEM_LOW));
                 return vfn;
             }
         }
@@ -301,6 +299,8 @@ vmmap_t *vmmap_clone(vmmap_t *map)
 {
     // NOT_YET_IMPLEMENTED("VM: vmmap_clone");
 
+    vmmap_collapse(map);
+
     // Create a new vmmap
     vmmap_t *new_vmmap = vmmap_create();
     if (new_vmmap == NULL)
@@ -308,8 +308,6 @@ vmmap_t *vmmap_clone(vmmap_t *map)
         return NULL;
     }
 
-    vmmap_collapse(map);
-
     // Iterate over the list of vmareas
     list_iterate(&map->vmm_list, vma, vmarea_t, vma_plink)
     {