Bite the bullet and try to get the locking correct the first^Wsecond time.
(subtle bugs like area->flagas modification not having the right memory
consistency could be a nightmare to track down)
Signed-off-by: Nick Piggin <[email protected]>
Index: linux-2.6/mm/vmalloc.c
===================================================================
--- linux-2.6.orig/mm/vmalloc.c
+++ linux-2.6/mm/vmalloc.c
@@ -256,16 +256,15 @@ struct vm_struct *get_vm_area_node(unsig
return __get_vm_area_node(size, flags, VMALLOC_START, VMALLOC_END, node);
}
-static struct vm_struct *find_vm_area(void *addr)
+/* Caller must hold vmlist_lock */
+static struct vm_struct *__find_vm_area(void *addr)
{
struct vm_struct *tmp;
- write_lock(&vmlist_lock);
for (tmp = vmlist; tmp != NULL; tmp = tmp->next) {
if (tmp->addr == addr)
break;
}
- write_unlock(&vmlist_lock);
return tmp;
}
@@ -529,9 +528,10 @@ void *vmalloc_user(unsigned long size)
void *ret;
ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
- area = find_vm_area(ret);
- BUG_ON(!area);
+ write_lock(&vmlist_lock);
+ area = __find_vm_area(ret);
area->flags |= VM_USERMAP;
+ write_unlock(&vmlist_lock);
return ret;
}
@@ -604,9 +604,10 @@ void *vmalloc_32_user(unsigned long size
void *ret;
ret = __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
- area = find_vm_area(ret);
- BUG_ON(!area);
+ write_lock(&vmlist_lock);
+ area = __find_vm_area(ret);
area->flags |= VM_USERMAP;
+ write_unlock(&vmlist_lock);
return ret;
}
@@ -712,15 +713,17 @@ int remap_vmalloc_range(struct vm_area_s
if ((PAGE_SIZE-1) & (unsigned long)addr)
return -EINVAL;
- area = find_vm_area(addr);
+ read_lock(&vmlist_lock);
+ area = __find_vm_area(addr);
if (!area)
- return -EINVAL;
+ goto out_einval_locked;
if (!(area->flags & VM_USERMAP))
- return -EINVAL;
+ goto out_einval_locked;
if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
- return -EINVAL;
+ goto out_einval_locked;
+ read_unlock(&vmlist_lock);
addr = (void *)((unsigned long)addr + (pgoff << PAGE_SHIFT));
do {
@@ -738,6 +741,10 @@ int remap_vmalloc_range(struct vm_area_s
vma->vm_flags |= VM_RESERVED;
return ret;
+
+out_einval_locked:
+ read_unlock(&vmlist_lock);
+ return -EINVAL;
}
EXPORT_SYMBOL(remap_vmalloc_range);
-
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