Jason Wang
2021-Nov-23 02:10 UTC
[PATCH] vdpa_sim: avoid putting an uninitialized iova_domain
On Mon, Nov 22, 2021 at 8:22 PM Longpeng(Mike) <longpeng2 at huawei.com> wrote:> > From: Longpeng <longpeng2 at huawei.com> > > The system will crash if we put an uninitialized iova_domain, this > could happen when an error occurs before initializing the iova_domain > in vdpasim_create(). > > BUG: kernel NULL pointer dereference, address: 0000000000000000 > ... > RIP: 0010:__cpuhp_state_remove_instance+0x96/0x1c0 > ... > Call Trace: > <TASK> > put_iova_domain+0x29/0x220 > vdpasim_free+0xd1/0x120 [vdpa_sim] > vdpa_release_dev+0x21/0x40 [vdpa] > device_release+0x33/0x90 > kobject_release+0x63/0x160 > vdpasim_create+0x127/0x2a0 [vdpa_sim] > vdpasim_net_dev_add+0x7d/0xfe [vdpa_sim_net] > vdpa_nl_cmd_dev_add_set_doit+0xe1/0x1a0 [vdpa] > genl_family_rcv_msg_doit+0x112/0x140 > genl_rcv_msg+0xdf/0x1d0 > ... > > So we must make sure the iova_domain is already initialized before > put it. > > In addition, we may get the following warning in this case: > WARNING: ... drivers/iommu/iova.c:344 iova_cache_put+0x58/0x70 > > So we must make sure the iova_cache_put() is invoked only if the > iova_cache_get() is already invoked. Let's fix it together. > > Signed-off-by: Longpeng <longpeng2 at huawei.com>Acked-by: Jason Wang <jasowang at redhat.com>> --- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c > index 5f484fff8dbe..41b0cd17fcba 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c > @@ -591,8 +591,11 @@ static void vdpasim_free(struct vdpa_device *vdpa) > vringh_kiov_cleanup(&vdpasim->vqs[i].in_iov); > } > > - put_iova_domain(&vdpasim->iova); > - iova_cache_put(); > + if (vdpa_get_dma_dev(vdpa)) { > + put_iova_domain(&vdpasim->iova); > + iova_cache_put(); > + } > + > kvfree(vdpasim->buffer); > if (vdpasim->iommu) > vhost_iotlb_free(vdpasim->iommu); > -- > 2.27.0 >