Re: WARNING: kmalloc bug in input_mt_init_slots
From: Dmitry Torokhov
Date: Tue Oct 16 2018 - 20:10:04 EST
On Thu, Sep 27, 2018 at 07:35:37AM -0700, Matthew Wilcox wrote:
> 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.
No. No sane input device can track so many contacts so we need to use
kvzalloc(). Failing to allocate memory is proper response here.