Re: [PATCH] mm: avoid setting up anonymous pages into file mapping

[Boaz Harrosh]

On 07/05/2015 06:44 PM, Kirill A. Shutemov wrote:
>> Again that could mean a theoretical regression for some in-tree driver,
>> do you know of any such driver?
> 
> I did very little testing with the patch: boot kvm with Fedora and run
> trinity there for a while. More testing is required.
> 

It seems more likely to be a bug in some obscure real HW driver, then
anything virtualized.

Let me run a quick search and see if I can see any obvious candidates
for this ...

<arch/x86/kernel/vsyscall_64.c>
static struct vm_operations_struct gate_vma_ops = {
	.name = gate_vma_name,
};

Perhaps it was done for this one
</arch/x86/kernel/vsyscall_64.c>

<arch/x86/mm/mpx.c>
static struct vm_operations_struct mpx_vma_ops = {
	.name = mpx_mapping_name,
};

Or this

</arch/x86/mm/mpx.c>

<more>
static const struct vm_operations_struct pci_mmap_ops = {

static const struct vm_operations_struct mmap_mem_ops = {

...
</more>

I was looking in-tree for any vm_operations_struct declaration without a .fault
member, there are these above and a slue of HW drivers that only have an .open
and .close so those might populate at open time and never actually ever fault.

Please have a quick look, I did not. I agree about the possible security badness.

Thanks
Boaz

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