From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [PATCH net V3 2/2] ptr_ring: fail on large queue size (>64K) Date: Thu, 8 Feb 2018 11:59:25 +0800 Message-ID: <1518062365-8596-2-git-send-email-jasowang@redhat.com> References: <1518062365-8596-1-git-send-email-jasowang@redhat.com> Cc: netdev@vger.kernel.org, Jason Wang To: mst@redhat.com Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:49702 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750806AbeBHD7e (ORCPT ); Wed, 7 Feb 2018 22:59:34 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1DBD7404008D for ; Thu, 8 Feb 2018 03:59:34 +0000 (UTC) In-Reply-To: <1518062365-8596-1-git-send-email-jasowang@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: We need limit the maximum size of queue, otherwise it may cause several side effects e.g slab will warn when the size exceeds KMALLOC_MAX_SIZE. Using KMALLOC_MAX_SIZE still looks too so this patch tries to limit it to 64K. This value could be revisited if we found a real case that needs more. Reported-by: syzbot+e4d4f9ddd4295539735d@syzkaller.appspotmail.com Fixes: 2e0ab8ca83c12 ("ptr_ring: array based FIFO for pointers") Signed-off-by: Jason Wang --- include/linux/ptr_ring.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h index 2af71a7..5858d48 100644 --- a/include/linux/ptr_ring.h +++ b/include/linux/ptr_ring.h @@ -44,6 +44,8 @@ struct ptr_ring { void **queue; }; +#define PTR_RING_MAX_ALLOC 65536 + /* Note: callers invoking this in a loop must use a compiler barrier, * for example cpu_relax(). * @@ -466,6 +468,8 @@ 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 > PTR_RING_MAX_ALLOC) + return NULL; return kvmalloc_array(size, sizeof(void *), gfp | __GFP_ZERO); } -- 2.7.4