From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH net] ptr_ring: fail early if queue occupies more than KMALLOC_MAX_SIZE Date: Wed, 7 Feb 2018 17:15:35 +0200 Message-ID: <20180207171422-mutt-send-email-mst@kernel.org> References: <1517990905-15737-1-git-send-email-jasowang@redhat.com> <14eecede-e053-9f97-cc09-5ab58cd4d2cf@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Jason Wang Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33646 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754150AbeBGPPg (ORCPT ); Wed, 7 Feb 2018 10:15:36 -0500 Content-Disposition: inline In-Reply-To: <14eecede-e053-9f97-cc09-5ab58cd4d2cf@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: 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 :) -- MST