From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751528AbcGROBg (ORCPT ); Mon, 18 Jul 2016 10:01:36 -0400 Received: from mail-pf0-f196.google.com ([209.85.192.196]:33739 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750732AbcGROBd (ORCPT ); Mon, 18 Jul 2016 10:01:33 -0400 From: Minfei Huang X-Google-Original-From: Minfei Huang To: mst@redhat.com, cornelia.huck@de.ibm.com Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, fanc.fnst@cn.fujitsu.com, Minfei Huang , Minfei Huang Subject: [PATCH v2] virtio_blk: Fix a slient kernel panic Date: Mon, 18 Jul 2016 22:01:29 +0800 Message-Id: <1468850489-40157-1-git-send-email-mnghuan@gmail.com> X-Mailer: git-send-email 2.7.4 (Apple Git-66) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We do a lot of memory allocation in function init_vq, and don't handle the allocation failure properly. Then this function will return 0, although initialization fails due to lacking memory. At that moment, kernel will panic in guest machine, if virtio is used to drive disk. To fix this bug, we should take care of allocation failure, and return correct value to let caller know what happen. Tested-by: Chao Fan Signed-off-by: Minfei Huang Signed-off-by: Minfei Huang --- v1: - Refactor the patch to make code more readable --- drivers/block/virtio_blk.c | 32 +++++++++++--------------------- 1 file changed, 11 insertions(+), 21 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 42758b5..d920512 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -381,9 +381,9 @@ static int init_vq(struct virtio_blk *vblk) { int err = 0; int i; - vq_callback_t **callbacks; - const char **names; - struct virtqueue **vqs; + vq_callback_t **callbacks = NULL; + const char **names = NULL; + struct virtqueue **vqs = NULL; unsigned short num_vqs; struct virtio_device *vdev = vblk->vdev; @@ -394,22 +394,16 @@ static int init_vq(struct virtio_blk *vblk) num_vqs = 1; vblk->vqs = kmalloc(sizeof(*vblk->vqs) * num_vqs, GFP_KERNEL); - if (!vblk->vqs) { - err = -ENOMEM; - goto out; - } + if (!vblk->vqs) + return -ENOMEM; names = kmalloc(sizeof(*names) * num_vqs, GFP_KERNEL); - if (!names) - goto err_names; - callbacks = kmalloc(sizeof(*callbacks) * num_vqs, GFP_KERNEL); - if (!callbacks) - goto err_callbacks; - vqs = kmalloc(sizeof(*vqs) * num_vqs, GFP_KERNEL); - if (!vqs) - goto err_vqs; + if (!names || !callbacks || !vqs) { + err = -ENOMEM; + goto out; + } for (i = 0; i < num_vqs; i++) { callbacks[i] = virtblk_done; @@ -420,7 +414,7 @@ static int init_vq(struct virtio_blk *vblk) /* Discover virtqueues and write information to configuration. */ err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names); if (err) - goto err_find_vqs; + goto out; for (i = 0; i < num_vqs; i++) { spin_lock_init(&vblk->vqs[i].lock); @@ -428,16 +422,12 @@ static int init_vq(struct virtio_blk *vblk) } vblk->num_vqs = num_vqs; - err_find_vqs: +out: kfree(vqs); - err_vqs: kfree(callbacks); - err_callbacks: kfree(names); - err_names: if (err) kfree(vblk->vqs); - out: return err; } -- 2.7.4 (Apple Git-66)