Re: WARNING in kmalloc_slab (3)

From: Dmitry Vyukov
Date: Mon Dec 04 2017 - 03:18:32 EST


On Mon, Dec 4, 2017 at 9:14 AM, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> On Sun, Dec 03, 2017 at 12:16:08PM -0800, Eric Biggers wrote:
>> Looks like BLKTRACESETUP doesn't limit the '.buf_nr' parameter, allowing anyone
>> who can open a block device to cause an extremely large kmalloc. Here's a
>> simplified reproducer:
>>
>
> There are lots of places which allow people to allocate as much as they
> want. With Syzcaller, you might want to just hard code a __GFP_NOWARN
> in to disable it.

Hi,

Hard code it where?

User-controllable allocation are supposed to use __GFP_NOWARN.