Jens Axboe <axboe@xxxxxxxxx> writes:
> On 1/17/19 5:48 AM, Roman Penyaev wrote:
>> On 2019-01-16 18:49, Jens Axboe wrote:
>>
>> [...]
>>
>>> +static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
>>> + struct io_uring_params *p)
>>> +{
>>> + struct io_sq_ring *sq_ring;
>>> + struct io_cq_ring *cq_ring;
>>> + size_t size;
>>> + int ret;
>>> +
>>> + sq_ring = io_mem_alloc(struct_size(sq_ring, array, p->sq_entries));
>>
>> It seems that sq_entries, cq_entries are not limited at all. Can nasty
>> app consume a lot of kernel pages calling io_setup_uring() from a loop
>> passing random entries number? (or even better: decreasing entries
>> number,
>> in order to consume all pages orders with min number of loops).
>
> Yes, that's an oversight, we should have a limit in place. I'll add that.
Can we charge the ring memory to the RLIMIT_MEMLOCK as well? I'd prefer
not to repeat the mistake of fs.aio-max-nr.
-Jeff
