Date:   Thu, 21 Apr 2022 16:40:59 +0000
From:   "Keller, Jacob E" <jacob.e.keller@...el.com>
To:     ivecera <ivecera@...hat.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
CC:     Fei Liu <feliu@...hat.com>,
        "moderated list:INTEL ETHERNET DRIVERS" 
        <intel-wired-lan@...ts.osuosl.org>, mschmidt <mschmidt@...hat.com>,
        "Brett Creeley" <brett.creeley@...el.com>,
        open list <linux-kernel@...r.kernel.org>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: RE: [Intel-wired-lan] [PATCH net v2] ice: Protect vf_state check by
 cfg_lock in ice_vc_process_vf_msg()



> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@...osl.org> On Behalf Of Ivan
> Vecera
> Sent: Tuesday, April 19, 2022 7:22 AM
> To: netdev@...r.kernel.org
> Cc: Fei Liu <feliu@...hat.com>; moderated list:INTEL ETHERNET DRIVERS <intel-
> wired-lan@...ts.osuosl.org>; mschmidt <mschmidt@...hat.com>; Brett Creeley
> <brett.creeley@...el.com>; open list <linux-kernel@...r.kernel.org>; Jakub
> Kicinski <kuba@...nel.org>; Paolo Abeni <pabeni@...hat.com>; David S. Miller
> <davem@...emloft.net>
> Subject: [Intel-wired-lan] [PATCH net v2] ice: Protect vf_state check by cfg_lock in
> ice_vc_process_vf_msg()
> 
> Previous patch labelled "ice: Fix incorrect locking in
> ice_vc_process_vf_msg()"  fixed an issue with ignored messages
> sent by VF driver but a small race window still left.
> 
> Recently caught trace during 'ip link set ... vf 0 vlan ...' operation:
> 
> [ 7332.995625] ice 0000:3b:00.0: Clearing port VLAN on VF 0
> [ 7333.001023] iavf 0000:3b:01.0: Reset indication received from the PF
> [ 7333.007391] iavf 0000:3b:01.0: Scheduling reset task
> [ 7333.059575] iavf 0000:3b:01.0: PF returned error -5 (IAVF_ERR_PARAM) to our
> request 3
> [ 7333.059626] ice 0000:3b:00.0: Invalid message from VF 0, opcode 3, len 4,
> error -1
> 
> Setting of VLAN for VF causes a reset of the affected VF using
> ice_reset_vf() function that runs with cfg_lock taken:
> 
> 1. ice_notify_vf_reset() informs IAVF driver that reset is needed and
>    IAVF schedules its own reset procedure
> 2. Bit ICE_VF_STATE_DIS is set in vf->vf_state
> 3. Misc initialization steps
> 4. ice_sriov_post_vsi_rebuild() -> ice_vf_set_initialized() and that
>    clears ICE_VF_STATE_DIS in vf->vf_state
> 
> Step 3 is mentioned race window because IAVF reset procedure runs in
> parallel and one of its step is sending of VIRTCHNL_OP_GET_VF_RESOURCES
> message (opcode==3). This message is handled in ice_vc_process_vf_msg()
> and if it is received during the mentioned race window then it's
> marked as invalid and error is returned to VF driver.
> 
> Protect vf_state check in ice_vc_process_vf_msg() by cfg_lock to avoid
> this race condition.
> 
> Fixes: e6ba5273d4ed ("ice: Fix race conditions between virtchnl handling and VF
> ndo ops")
> Tested-by: Fei Liu <feliu@...hat.com>
> Signed-off-by: Ivan Vecera <ivecera@...hat.com>

Thanks, this looks good to me.

Reviewed-by: Jacob Keller <jacob.e.keller@...el.com>

> ---
>  drivers/net/ethernet/intel/ice/ice_virtchnl.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_virtchnl.c
> b/drivers/net/ethernet/intel/ice/ice_virtchnl.c
> index 5612c032f15a..b72606c9e6d0 100644
> --- a/drivers/net/ethernet/intel/ice/ice_virtchnl.c
> +++ b/drivers/net/ethernet/intel/ice/ice_virtchnl.c
> @@ -3625,6 +3625,8 @@ void ice_vc_process_vf_msg(struct ice_pf *pf, struct
> ice_rq_event_info *event)
>  		return;
>  	}
> 
> +	mutex_lock(&vf->cfg_lock);
> +
>  	/* Check if VF is disabled. */
>  	if (test_bit(ICE_VF_STATE_DIS, vf->vf_states)) {
>  		err = -EPERM;
> @@ -3648,19 +3650,14 @@ void ice_vc_process_vf_msg(struct ice_pf *pf, struct
> ice_rq_event_info *event)
>  				      NULL, 0);
>  		dev_err(dev, "Invalid message from VF %d, opcode %d, len %d,
> error %d\n",
>  			vf_id, v_opcode, msglen, err);
> -		ice_put_vf(vf);
> -		return;
> +		goto finish;
>  	}
> 
> -	mutex_lock(&vf->cfg_lock);
> -
>  	if (!ice_vc_is_opcode_allowed(vf, v_opcode)) {
>  		ice_vc_send_msg_to_vf(vf, v_opcode,
>  				      VIRTCHNL_STATUS_ERR_NOT_SUPPORTED,
> NULL,
>  				      0);
> -		mutex_unlock(&vf->cfg_lock);
> -		ice_put_vf(vf);
> -		return;
> +		goto finish;
>  	}
> 
>  	switch (v_opcode) {
> @@ -3773,6 +3770,7 @@ void ice_vc_process_vf_msg(struct ice_pf *pf, struct
> ice_rq_event_info *event)
>  			 vf_id, v_opcode, err);
>  	}
> 
> +finish:
>  	mutex_unlock(&vf->cfg_lock);
>  	ice_put_vf(vf);
>  }
> --
> 2.35.1
> 
> _______________________________________________
> Intel-wired-lan mailing list
> Intel-wired-lan@...osl.org
> https://lists.osuosl.org/mailman/listinfo/intel-wired-lan

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