Jason Wang
2023-Mar-02 07:04 UTC
[PATCH] vhost-vdpa: free iommu domain after last use during cleanup
On Thu, Mar 2, 2023 at 12:32?AM Gautam Dawar <gautam.dawar at amd.com> wrote:> > Currently vhost_vdpa_cleanup() unmaps the DMA mappings by calling > `iommu_unmap(v->domain, map->start, map->size);` > from vhost_vdpa_general_unmap() when the parent vDPA driver doesn't > provide DMA config operations. > > However, the IOMMU domain referred to by `v->domain` is freed in > vhost_vdpa_free_domain() before vhost_vdpa_cleanup() in > vhost_vdpa_release() which results in NULL pointer de-reference. > Accordingly, moving the call to vhost_vdpa_free_domain() in > vhost_vdpa_cleanup() would makes sense. This will also help > detaching the dma device in error handling of vhost_vdpa_alloc_domain(). > > This issue was observed on terminating QEMU with SIGQUIT. > > Fixes: 037d4305569a ("vhost-vdpa: call vhost_vdpa_cleanup during the release") > Signed-off-by: Gautam Dawar <gautam.dawar at amd.com>Acked-by: Jason Wang <jasowang at redhat.com> Thanks> --- > drivers/vhost/vdpa.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index ec32f785dfde..b7657984dd8d 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -1134,6 +1134,7 @@ static int vhost_vdpa_alloc_domain(struct vhost_vdpa *v) > > err_attach: > iommu_domain_free(v->domain); > + v->domain = NULL; > return ret; > } > > @@ -1178,6 +1179,7 @@ static void vhost_vdpa_cleanup(struct vhost_vdpa *v) > vhost_vdpa_remove_as(v, asid); > } > > + vhost_vdpa_free_domain(v); > vhost_dev_cleanup(&v->vdev); > kfree(v->vdev.vqs); > } > @@ -1250,7 +1252,6 @@ static int vhost_vdpa_release(struct inode *inode, struct file *filep) > vhost_vdpa_clean_irq(v); > vhost_vdpa_reset(v); > vhost_dev_stop(&v->vdev); > - vhost_vdpa_free_domain(v); > vhost_vdpa_config_put(v); > vhost_vdpa_cleanup(v); > mutex_unlock(&d->mutex); > -- > 2.30.1 >