On Wed, May 14, 2014 at 4:16 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 14 May 2014 16:01:22 -0700 Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>
>> The access should fail, but it shouldn't oops.
>>
>> Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
>> ---
>>
>> The oops can be triggered in qemu using -no-hpet (but not nohpet) by
>> running a 32-bit program and reading a couple of pages before the vdso.
>
> This sentence is the best part of the changelog! People often do this
> - they put all the good stuff after the ^---. I always move it into
> the changelog.
>
> So how old is this bug?
New in 3.15.
>
>> --- a/arch/x86/vdso/vdso32-setup.c
>> +++ b/arch/x86/vdso/vdso32-setup.c
>> @@ -147,6 +147,8 @@ int __init sysenter_setup(void)
>> return 0;
>> }
>>
>> +static struct page *no_pages[] = {NULL};
>
> nit: this could be local to arch_setup_additional_pages().
Will do.
>
>> /* Setup a VMA at program startup for the vsyscall page */
>> int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>> {
>> @@ -192,7 +194,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
>> addr - VDSO_OFFSET(VDSO_PREV_PAGES),
>> VDSO_OFFSET(VDSO_PREV_PAGES),
>> VM_READ,
>> - NULL);
>> + no_pages);
>>
>> if (IS_ERR(vma)) {
>> ret = PTR_ERR(vma);
>
--Andy
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>