On Fri, Aug 09, 2024 at 12:59:11PM +0800, Gui-Dong Han wrote:
> This patch addresses an issue with improper reference count handling in the
> ice_sriov_set_msix_vec_count() function. Specifically, the function calls
> ice_get_vf_by_id(), which increments the reference count of the vf pointer.
> If the subsequent call to ice_get_vf_vsi() fails, the function currently
> returns an error without decrementing the reference count of the vf
> pointer, leading to a reference count leak.
>
> The correct behavior, as implemented in this patch, is to decrement the
> reference count using ice_put_vf(vf) before returning an error when vsi
> is NULL.
>
> This bug was identified by an experimental static analysis tool developed
> by our team. The tool specializes in analyzing reference count operations
> and identifying potential mismanagement of reference counts. In this case,
> the tool flagged the missing decrement operation as a potential issue,
> leading to this patch.
>
> Fixes: 4035c72dc1ba ("ice: reconfig host after changing MSI-X on VF")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Gui-Dong Han <hanguidong02@xxxxxxxxxxx>
Thanks Gui-Dong Han,
I agree with your analysis.
However, I wonder if the same resource leak can occur
in the unroll label, if the if clause results in a return.
It is around line 1444 without your patch applied.
vf->first_vector_idx = ice_sriov_get_irqs(pf, vf->num_msix);
if (vf->first_vector_idx < 0)
return -EINVAL;
> ---
> drivers/net/ethernet/intel/ice/ice_sriov.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice_sriov.c b/drivers/net/ethernet/intel/ice/ice_sriov.c
> index 55ef33208456..eb5030aba9a5 100644
> --- a/drivers/net/ethernet/intel/ice/ice_sriov.c
> +++ b/drivers/net/ethernet/intel/ice/ice_sriov.c
> @@ -1096,8 +1096,10 @@ int ice_sriov_set_msix_vec_count(struct pci_dev *vf_dev, int msix_vec_count)
> return -ENOENT;
>
> vsi = ice_get_vf_vsi(vf);
> - if (!vsi)
> + if (!vsi) {
> + ice_put_vf(vf);
> return -ENOENT;
> + }
>
> prev_msix = vf->num_msix;
> prev_queues = vf->num_vf_qs;
> --
> 2.25.1
>
>
