Mitsuo Hayasaka <mitsuo.hayasaka.hu <at> hitachi.com> writes:
>
> The /proc/vmallocinfo shows information about vmalloc allocations in vmlist
> that is a linklist of vm_struct. It, however, may access pages field of
> vm_struct where a page was not allocated. This results in a null pointer
> access and leads to a kernel panic.
> +static void insert_vmalloc_vmlist(struct vm_struct *vm)
> +{
> + struct vm_struct *tmp, **p;
>
> + vm->flags &= ~VM_UNLIST;
> write_lock(&vmlist_lock);
> for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) {
> if (tmp->addr >= vm->addr)
> @@ -1275,6 +1279,13 @@ static void insert_vmalloc_vm(struct vm_struct *vm,
struct vmap_area *va,
> write_unlock(&vmlist_lock);
> }
Hi Mitsuo:
Is it needed to set the VM_UNLIST after vm_struct added to vmlist here?
or put it into lock protection?
Thanks
-Wanlong Gao
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