Changeset c0697c4c in mainline

Timestamp:

2007-12-16T18:45:48Z (16 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

2a3db79

Parents:

cb08279

Message:

Fix a bug in anonymous address space area sharing. Call the backend's share
function only if the source area is not already shared. Otherwise increment the
sh_info refcount. Without this fix, the kernel will try to recreate the pagemap
if three and more address space areas attempt to share the same data.

Location:

kernel/generic/src/mm

Files:

• as.c (modified) (3 diffs)
• backend_elf.c (modified) (1 diff)

kernel/generic/src/mm/as.c

@@ -641 +641 @@
  */
 int as_area_share(as_t *src_as, uintptr_t src_base, size_t acc_size,
-                  as_t *dst_as, uintptr_t dst_base, int dst_flags_mask)
+    as_t *dst_as, uintptr_t dst_base, int dst_flags_mask)
 {
         ipl_t ipl;
@@ -703 +703 @@
                 btree_create(&sh_info->pagemap);
                 src_area->sh_info = sh_info;
+                /*
+                 * Call the backend to setup sharing.
+                 */
+                src_area->backend->share(src_area);
         } else {
                 mutex_lock(&sh_info->lock);
@@ -708 +712 @@
                 mutex_unlock(&sh_info->lock);
         }
-
-        src_area->backend->share(src_area);
 
         mutex_unlock(&src_area->lock);

kernel/generic/src/mm/backend_elf.c

@@ -305 +305 @@
                          */
                         if (!(area->flags & AS_AREA_WRITE))
-                                if (base + count*PAGE_SIZE <= start_anon)
+                                if (base + count * PAGE_SIZE <= start_anon)
                                         continue;