From: Longpeng longpeng2@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.
Cc: stable@vger.kernel.org Fixes: 4080fc106750 ("vdpa_sim: use iova module to allocate IOVA addresses") Signed-off-by: Longpeng longpeng2@huawei.com Acked-by: Jason Wang jasowang@redhat.com Reviewed-by: Stefano Garzarella sgarzare@redhat.com --- Changes v2 -> v1: - add "Fixes" tag [Parav, Jason]
--- 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 5f484ff..41b0cd1 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);