From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: [PATCH net V2 2/2] ptr_ring: fail on large queue size (>64K) Date: Thu, 8 Feb 2018 11:21:41 +0800 Message-ID: <1518060101-19071-2-git-send-email-jasowang@redhat.com> References: <1518060101-19071-1-git-send-email-jasowang@redhat.com> Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Jason Wang To: mst@redhat.com Return-path: In-Reply-To: <1518060101-19071-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 9c3b748..2520daa 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