Messages in this thread Patch in this message | | | Date | Mon, 3 Aug 2009 20:15:57 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [BUGFIX][PATCH 1/3] unmap vmalloc area after hide it |
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This is necessary to garantee sane access of vread/vwrite.
== From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
vmap area should be purged after vm_struct is removed from the list because vread/vwrite etc...believes the range is valid while it's on vm_struct list.
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --- mm/vmalloc.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
Index: linux-2.6.31-rc4/mm/vmalloc.c =================================================================== --- linux-2.6.31-rc4.orig/mm/vmalloc.c 2009-07-31 15:51:56.000000000 +0900 +++ linux-2.6.31-rc4/mm/vmalloc.c 2009-07-31 15:52:42.000000000 +0900 @@ -1256,17 +1256,21 @@ if (va && va->flags & VM_VM_AREA) { struct vm_struct *vm = va->private; struct vm_struct *tmp, **p; - - vmap_debug_free_range(va->va_start, va->va_end); - free_unmap_vmap_area(va); - vm->size -= PAGE_SIZE; - + /* + * remove from list and disallow access to this vm_struct + * before unmap. (address range confliction is maintained by + * vmap.) + */ write_lock(&vmlist_lock); for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next) ; *p = tmp->next; write_unlock(&vmlist_lock); + vmap_debug_free_range(va->va_start, va->va_end); + free_unmap_vmap_area(va); + vm->size -= PAGE_SIZE; + return vm; } return NULL;
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