>>> +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>>> +{
>>> + int ret;
>>> + unsigned long addr;
>>> + struct mm_struct *mm = current->mm;
>>> +
>>> + down_write(&mm->mmap_sem);
>>> +
>>> + addr = vdso_addr(mm->start_stack);
>>> +
>>> + addr = get_unmapped_area(NULL, addr, PAGE_SIZE, 0, 0);
>>> + if (IS_ERR_VALUE(addr)) {
>>> + ret = addr;
>>> + goto up_fail;
>>> + }
>>> +
>>> + ret = install_special_mapping(mm, addr, PAGE_SIZE,
>>> + VM_READ|VM_EXEC|
>>> + VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
>>> + VM_ALWAYSDUMP,
>>> + &vdso_page);
>>> +
>>> + if (ret)
>>> + goto up_fail;
>>> +
>>> + mm->context.vdso = (void *)addr;
>>> +
>>> +up_fail:
>>
>> It seems that this is an unexpected condition that probably indicates
>> a failure of the expected state of the process at this point. Perhaps
>> a pr_err() or pr_warning() would be appropriate?
>>
>>> + up_write(&mm->mmap_sem);
>>> + return ret;
>>> +}
>
> Really it should always succeed. Something is seriously wrong if you
> cannot map that page and we should probably panic().
It seems like it may be recoverable, so perhaps BUG() is better.
> David Daney
David VomLehn
