Re: [PATCH] vdpa/vp_vdpa: fix kfree a wrong pointer in vp_vdpa_remove

[Cindy Lu]

On Wed, 7 Dec 2022 at 19:23, Nanyong Sun <sunnanyong@xxxxxxxxxx> wrote:
>
> From: Rong Wang <wangrong68@xxxxxxxxxx>
>
> In vp_vdpa_remove(), the code kfree(&vp_vdpa_mgtdev->mgtdev.id_table) uses
> a reference of pointer as the argument of kfree, which is the wrong pointer
> and then may hit crash like this:
>
> Unable to handle kernel paging request at virtual address 00ffff003363e30c
> Internal error: Oops: 96000004 [#1] SMP
> Call trace:
>  rb_next+0x20/0x5c
>  ext4_readdir+0x494/0x5c4 [ext4]
>  iterate_dir+0x168/0x1b4
>  __se_sys_getdents64+0x68/0x170
>  __arm64_sys_getdents64+0x24/0x30
>  el0_svc_common.constprop.0+0x7c/0x1bc
>  do_el0_svc+0x2c/0x94
>  el0_svc+0x20/0x30
>  el0_sync_handler+0xb0/0xb4
>  el0_sync+0x160/0x180
> Code: 54000220 f9400441 b4000161 aa0103e0 (f9400821)
> SMP: stopping secondary CPUs
> Starting crashdump kernel...
>
> Fixes: ffbda8e9df10 ("vdpa/vp_vdpa : add vdpa tool support in vp_vdpa")
> Signed-off-by: Rong Wang <wangrong68@xxxxxxxxxx>
> Signed-off-by: Nanyong Sun <sunnanyong@xxxxxxxxxx>
> ---
>  drivers/vdpa/virtio_pci/vp_vdpa.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index d448db0c4de3..8fe267ca3e76 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -647,7 +647,7 @@ static void vp_vdpa_remove(struct pci_dev *pdev)
>         mdev = vp_vdpa_mgtdev->mdev;
>         vp_modern_remove(mdev);
>         vdpa_mgmtdev_unregister(&vp_vdpa_mgtdev->mgtdev);
> -       kfree(&vp_vdpa_mgtdev->mgtdev.id_table);
> +       kfree(vp_vdpa_mgtdev->mgtdev.id_table);
>         kfree(mdev);
>         kfree(vp_vdpa_mgtdev);
>  }
> --
> 2.25.1
>
Reviewed-by: Cindy Lu <lulu@xxxxxxxxxx>