Re: [linux-next-20130422] Bug in SLAB?

[Tetsuo Handa]

Christoph Lameter wrote:
> On Sat, 4 May 2013, Tetsuo Handa wrote:
> 
> > Christoph Lameter wrote:
> > > Ok could I see the kernel logs with the warnings?
> > Sure.
> 
> These are exclusively from the module load. So the kernel seems to be
> clean of large kmalloc's ?
> 
There are modules (e.g. TOMOYO) which do not check for KMALLOC_MAX_SIZE limit
and expect kmalloc() larger than KMALLOC_MAX_SIZE bytes to return NULL.

As far as I know, such modules sequentially double the buffer size. Therefore,
as long as request for KMALLOC_MAX_SIZE * 2 bytes returns NULL, they won't
trigger oops by requesting for KMALLOC_MAX_SIZE * 8 bytes.

The testcase I wrote is for module (I don't know if there is one) which
requests for KMALLOC_MAX_SIZE * 8 bytes without requesting for
KMALLOC_MAX_SIZE * 2 bytes and/or KMALLOC_MAX_SIZE * 4 bytes.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/