From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH 05/15] Add io_uring IO interface Date: Thu, 17 Jan 2019 07:01:07 -0700 Message-ID: References: <20190116175003.17880-1-axboe@kernel.dk> <20190116175003.17880-6-axboe@kernel.dk> <718b4d1fbe9f97592d6d7b76d7a4537d@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org, hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, linux-block-owner@vger.kernel.org To: Roman Penyaev Return-path: In-Reply-To: <718b4d1fbe9f97592d6d7b76d7a4537d@suse.de> Content-Language: en-US Sender: owner-linux-aio@kvack.org List-Id: linux-fsdevel.vger.kernel.org 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. -- Jens Axboe -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@kvack.org. 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[66.29.188.166]) by smtp.gmail.com with ESMTPSA id r4sm5288400pgn.54.2019.01.17.06.01.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Jan 2019 06:01:09 -0800 (PST) Subject: Re: [PATCH 05/15] Add io_uring IO interface To: Roman Penyaev Cc: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org, hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, linux-block-owner@vger.kernel.org References: <20190116175003.17880-1-axboe@kernel.dk> <20190116175003.17880-6-axboe@kernel.dk> <718b4d1fbe9f97592d6d7b76d7a4537d@suse.de> From: Jens Axboe Message-ID: Date: Thu, 17 Jan 2019 07:01:07 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <718b4d1fbe9f97592d6d7b76d7a4537d@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Message-ID: <20190117140107.0v4gBvijQqMTj7SZyKzUY6SkGr1IKo24EFDrzia_2vw@z> 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. -- Jens Axboe