Re: WARNING: kmalloc bug in input_mt_init_slots

From: Matthew Wilcox
Date: Thu Sep 27 2018 - 10:35:46 EST


On Mon, Sep 24, 2018 at 11:41:58AM -0700, Dmitry Torokhov wrote:
> > How large is the allocation? AFACIT nRequests larger than KMALLOC_MAX_SIZE
> > are larger than the maximum allowed by the page allocator. Thus the warning
> > and the NULL return.
>
> The size in this particular case is being derived from a value passed
> from userspace. Input core does not care about any limits on size of
> memory kmalloc() can support and is perfectly happy with getting NULL
> and telling userspace to go away with their silly requests by returning
> -ENOMEM.
>
> For the record: I definitely do not want to pre-sanitize size neither in
> uinput nor in input core.

Probably should be using kvzalloc then.