From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751725AbeBHDEZ (ORCPT ); Wed, 7 Feb 2018 22:04:25 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:45508 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750807AbeBHDEY (ORCPT ); Wed, 7 Feb 2018 22:04:24 -0500 Subject: Re: [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE To: "Michael S. Tsirkin" Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org References: <1517990905-15737-1-git-send-email-jasowang@redhat.com> <14eecede-e053-9f97-cc09-5ab58cd4d2cf@redhat.com> <20180207171422-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: Date: Thu, 8 Feb 2018 11:04:18 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <20180207171422-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年02月07日 23:15, Michael S. Tsirkin wrote: > On Wed, Feb 07, 2018 at 05:17:59PM +0800, Jason Wang wrote: >> >> On 2018年02月07日 16:08, Jason Wang wrote: >>> To avoid slab to warn about exceeded size, fail early if queue >>> occupies more than KMALLOC_MAX_SIZE. >>> >>> Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com >>> Signed-off-by: Jason Wang >>> --- >>> include/linux/ptr_ring.h | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h >>> index 1883d61..4b862da 100644 >>> --- a/include/linux/ptr_ring.h >>> +++ b/include/linux/ptr_ring.h >>> @@ -466,6 +466,8 @@ static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r, >>> static inline void **__ptr_ring_init_queue_alloc(unsigned int size, gfp_t gfp) >>> { >>> + if (size > KMALLOC_MAX_SIZE) >>> + return NULL; >>> return kcalloc(size, sizeof(void *), gfp); >>> } >> Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") > That's probably not enough. How about switching to kvmalloc and limiting > this drastically to e.g. 64K. I vaguely remember that some wise man said > that should be enough for everybody :) > Okay, let me post a V2 to see if there's any objection. Thanks