[PATCH] net/iavf: fix core dump when the link is unstable

[Bruce Richardson]

On Tue, Aug 06, 2024 at 08:35:27AM +0800, Kaiwen Deng wrote:
> Physical link instability may cause a core dump.
> Unstable physical links can result in a large number of link
> change events.Link change events captured by vf before vf
> resources are allocated will result in a core dump.
> 
> This commit will check if vf_res is invalid before calling it.
> 
> Fixes: 5e03e316c753 ("net/iavf: handle virtchnl event message without interrupt")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Kaiwen Deng <kaiwenx.deng at intel.com>
Acked-by: Bruce Richardson <bruce.richardson at intel.com>

> ---
>  drivers/net/iavf/iavf_vchnl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/iavf/iavf_vchnl.c b/drivers/net/iavf/iavf_vchnl.c
> index 6d5969f084..b85debd40d 100644
> --- a/drivers/net/iavf/iavf_vchnl.c
> +++ b/drivers/net/iavf/iavf_vchnl.c
> @@ -255,7 +255,7 @@ iavf_read_msg_from_pf(struct iavf_adapter *adapter, uint16_t buf_len,
>  		case VIRTCHNL_EVENT_LINK_CHANGE:
>  			vf->link_up =
>  				vpe->event_data.link_event.link_status;
> -			if (vf->vf_res->vf_cap_flags &
> +			if (vf->vf_res != NULL && vf->vf_res->vf_cap_flags &
>  				VIRTCHNL_VF_CAP_ADV_LINK_SPEED) {

Since we are adjusting the conditional, we might as well fix the
indentation of it while we are at it. We can use up to 100 columns in DPDK
code, so there is no need to split the flags comparison across two lines.
Also the line continuation should not use a single tab indent - that makes
it look part of the body of the "if" statement, not part of the conditional
itself.
Will fix this on apply.

Thanks.