Subject: Re: [PATCH iwl-net v3 1/6] ice: move netif_queue_set_napi to rtnl-protected sections

From: Maciej Fijalkowski <[email-masked]>
Date: Tue, 20 Aug 2024 14:31:51 +0200

On Mon, Aug 19, 2024 at 12:05:38PM +0200, Larysa Zaremba wrote:
> Currently, netif_queue_set_napi() is called from ice_vsi_rebuild() that is
> not rtnl-locked when called from the reset. This creates the need to take
> the rtnl_lock just for a single function and complicates the
> synchronization with .ndo_bpf. At the same time, there no actual need to
> fill napi-to-queue information at this exact point.
> 
> Fill napi-to-queue information when opening the VSI and clear it when the
> VSI is being closed. Those routines are already rtnl-locked.
> 
> Also, rewrite napi-to-queue assignment in a way that prevents inclusion of
> XDP queues, as this leads to out-of-bounds writes, such as one below.
> 
> [  +0.000004] BUG: KASAN: slab-out-of-bounds in netif_queue_set_napi+0x1c2/0x1e0
> [  +0.000012] Write of size 8 at addr ffff889881727c80 by task bash/7047
> [  +0.000006] CPU: 24 PID: 7047 Comm: bash Not tainted 6.10.0-rc2+ #2
> [  +0.000004] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0014.082620210524 08/26/2021
> [  +0.000003] Call Trace:
> [  +0.000003]  <TASK>
> [  +0.000002]  dump_stack_lvl+0x60/0x80
> [  +0.000007]  print_report+0xce/0x630
> [  +0.000007]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
> [  +0.000007]  ? __virt_addr_valid+0x1c9/0x2c0
> [  +0.000005]  ? netif_queue_set_napi+0x1c2/0x1e0
> [  +0.000003]  kasan_report+0xe9/0x120
> [  +0.000004]  ? netif_queue_set_napi+0x1c2/0x1e0
> [  +0.000004]  netif_queue_set_napi+0x1c2/0x1e0
> [  +0.000005]  ice_vsi_close+0x161/0x670 [ice]
> [  +0.000114]  ice_dis_vsi+0x22f/0x270 [ice]
> [  +0.000095]  ice_pf_dis_all_vsi.constprop.0+0xae/0x1c0 [ice]
> [  +0.000086]  ice_prepare_for_reset+0x299/0x750 [ice]
> [  +0.000087]  pci_dev_save_and_disable+0x82/0xd0
> [  +0.000006]  pci_reset_function+0x12d/0x230
> [  +0.000004]  reset_store+0xa0/0x100
> [  +0.000006]  ? __pfx_reset_store+0x10/0x10
> [  +0.000002]  ? __pfx_mutex_lock+0x10/0x10
> [  +0.000004]  ? __check_object_size+0x4c1/0x640
> [  +0.000007]  kernfs_fop_write_iter+0x30b/0x4a0
> [  +0.000006]  vfs_write+0x5d6/0xdf0
> [  +0.000005]  ? fd_install+0x180/0x350
> [  +0.000005]  ? __pfx_vfs_write+0x10/0xA10
> [  +0.000004]  ? do_fcntl+0x52c/0xcd0
> [  +0.000004]  ? kasan_save_track+0x13/0x60
> [  +0.000003]  ? kasan_save_free_info+0x37/0x60
> [  +0.000006]  ksys_write+0xfa/0x1d0
> [  +0.000003]  ? __pfx_ksys_write+0x10/0x10
> [  +0.000002]  ? __x64_sys_fcntl+0x121/0x180
> [  +0.000004]  ? _raw_spin_lock+0x87/0xe0
> [  +0.000005]  do_syscall_64+0x80/0x170
> [  +0.000007]  ? _raw_spin_lock+0x87/0xe0
> [  +0.000004]  ? __pfx__raw_spin_lock+0x10/0x10
> [  +0.000003]  ? file_close_fd_locked+0x167/0x230
> [  +0.000005]  ? syscall_exit_to_user_mode+0x7d/0x220
> [  +0.000005]  ? do_syscall_64+0x8c/0x170
> [  +0.000004]  ? do_syscall_64+0x8c/0x170
> [  +0.000003]  ? do_syscall_64+0x8c/0x170
> [  +0.000003]  ? fput+0x1a/0x2c0
> [  +0.000004]  ? filp_close+0x19/0x30
> [  +0.000004]  ? do_dup2+0x25a/0x4c0
> [  +0.000004]  ? __x64_sys_dup2+0x6e/0x2e0
> [  +0.000002]  ? syscall_exit_to_user_mode+0x7d/0x220
> [  +0.000004]  ? do_syscall_64+0x8c/0x170
> [  +0.000003]  ? __count_memcg_events+0x113/0x380
> [  +0.000005]  ? handle_mm_fault+0x136/0x820
> [  +0.000005]  ? do_user_addr_fault+0x444/0xa80
> [  +0.000004]  ? clear_bhb_loop+0x25/0x80
> [  +0.000004]  ? clear_bhb_loop+0x25/0x80
> [  +0.000002]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [  +0.000005] RIP: 0033:0x7f2033593154
> 
> Fixes: 080b0c8d6d26 ("ice: Fix ASSERT_RTNL() warning during certain scenarios")

Shouldn't you include:
Fixes: 91fdbce7e8d6 ("ice: Add support in the driver for associating queue with napi")

as we were iterating over XDP rings that were attached to q_vectors from
the very beginning?

> Reviewed-by: Wojciech Drewek <[email-masked]>
> Reviewed-by: Jacob Keller <[email-masked]>
> Reviewed-by: Amritha Nambiar <[email-masked]>
> Tested-by: Chandan Kumar Rout <[email-masked]>
> Signed-off-by: Larysa Zaremba <[email-masked]>
> ---
>  drivers/net/ethernet/intel/ice/ice_base.c |  11 +-
>  drivers/net/ethernet/intel/ice/ice_lib.c  | 129 ++++++----------------
>  drivers/net/ethernet/intel/ice/ice_lib.h  |  10 +-
>  drivers/net/ethernet/intel/ice/ice_main.c |  17 ++-
>  4 files changed, 49 insertions(+), 118 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
> index f448d3a84564..c158749a80e0 100644
> --- a/drivers/net/ethernet/intel/ice/ice_base.c
> +++ b/drivers/net/ethernet/intel/ice/ice_base.c
> @@ -190,16 +190,11 @@ static void ice_free_q_vector(struct ice_vsi *vsi, int v_idx)
>  	}
>  	q_vector = vsi->q_vectors[v_idx];
>  
> -	ice_for_each_tx_ring(tx_ring, q_vector->tx) {
> -		ice_queue_set_napi(vsi, tx_ring->q_index, NETDEV_QUEUE_TYPE_TX,
> -				   NULL);
> +	ice_for_each_tx_ring(tx_ring, vsi->q_vectors[v_idx]->tx)
>  		tx_ring->q_vector = NULL;
> -	}
> -	ice_for_each_rx_ring(rx_ring, q_vector->rx) {
> -		ice_queue_set_napi(vsi, rx_ring->q_index, NETDEV_QUEUE_TYPE_RX,
> -				   NULL);
> +
> +	ice_for_each_rx_ring(rx_ring, vsi->q_vectors[v_idx]->rx)
>  		rx_ring->q_vector = NULL;
> -	}
>  
>  	/* only VSI with an associated netdev is set up with NAPI */
>  	if (vsi->netdev)
> diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
> index 03c4df4ed585..5f2ddcaf7031 100644
> --- a/drivers/net/ethernet/intel/ice/ice_lib.c
> +++ b/drivers/net/ethernet/intel/ice/ice_lib.c
> @@ -2286,9 +2286,6 @@ static int ice_vsi_cfg_def(struct ice_vsi *vsi)
>  
>  		ice_vsi_map_rings_to_vectors(vsi);
>  
> -		/* Associate q_vector rings to napi */
> -		ice_vsi_set_napi_queues(vsi);
> -
>  		vsi->stat_offsets_loaded = false;
>  
>  		/* ICE_VSI_CTRL does not need RSS so skip RSS processing */
> @@ -2621,6 +2618,7 @@ void ice_vsi_close(struct ice_vsi *vsi)
>  	if (!test_and_set_bit(ICE_VSI_DOWN, vsi->state))
>  		ice_down(vsi);
>  
> +	ice_vsi_clear_napi_queues(vsi);
>  	ice_vsi_free_irq(vsi);
>  	ice_vsi_free_tx_rings(vsi);
>  	ice_vsi_free_rx_rings(vsi);
> @@ -2687,120 +2685,55 @@ void ice_dis_vsi(struct ice_vsi *vsi, bool locked)
>  }
>  
>  /**
> - * __ice_queue_set_napi - Set the napi instance for the queue
> - * @dev: device to which NAPI and queue belong
> - * @queue_index: Index of queue
> - * @type: queue type as RX or TX
> - * @napi: NAPI context
> - * @locked: is the rtnl_lock already held
> - *
> - * Set the napi instance for the queue. Caller indicates the lock status.
> - */
> -static void
> -__ice_queue_set_napi(struct net_device *dev, unsigned int queue_index,
> -		     enum netdev_queue_type type, struct napi_struct *napi,
> -		     bool locked)
> -{
> -	if (!locked)
> -		rtnl_lock();
> -	netif_queue_set_napi(dev, queue_index, type, napi);
> -	if (!locked)
> -		rtnl_unlock();
> -}
> -
> -/**
> - * ice_queue_set_napi - Set the napi instance for the queue
> - * @vsi: VSI being configured
> - * @queue_index: Index of queue
> - * @type: queue type as RX or TX
> - * @napi: NAPI context
> + * ice_vsi_set_napi_queues
> + * @vsi: VSI pointer
>   *
> - * Set the napi instance for the queue. The rtnl lock state is derived from the
> - * execution path.
> + * Associate queue[s] with napi for all vectors.
> + * The caller must hold rtnl_lock.
>   */
> -void
> -ice_queue_set_napi(struct ice_vsi *vsi, unsigned int queue_index,
> -		   enum netdev_queue_type type, struct napi_struct *napi)
> +void ice_vsi_set_napi_queues(struct ice_vsi *vsi)

this appears to be called only in ice_main.c. It should be moved there and
made a static function instead of having it in ice_lib.c.

Unless I overlooked something...

>  {
> -	struct ice_pf *pf = vsi->back;
> +	struct net_device *netdev = vsi->netdev;
> +	int q_idx, v_idx;
>  
> -	if (!vsi->netdev)
> +	if (!netdev)
>  		return;
>  
> -	if (current_work() == &pf->serv_task ||
> -	    test_bit(ICE_PREPARED_FOR_RESET, pf->state) ||
> -	    test_bit(ICE_DOWN, pf->state) ||
> -	    test_bit(ICE_SUSPENDED, pf->state))
> -		__ice_queue_set_napi(vsi->netdev, queue_index, type, napi,
> -				     false);
> -	else
> -		__ice_queue_set_napi(vsi->netdev, queue_index, type, napi,
> -				     true);
> -}
> +	ice_for_each_rxq(vsi, q_idx)
> +		netif_queue_set_napi(netdev, q_idx, NETDEV_QUEUE_TYPE_RX,
> +				     &vsi->rx_rings[q_idx]->q_vector->napi);
>  
> -/**
> - * __ice_q_vector_set_napi_queues - Map queue[s] associated with the napi
> - * @q_vector: q_vector pointer
> - * @locked: is the rtnl_lock already held
> - *
> - * Associate the q_vector napi with all the queue[s] on the vector.
> - * Caller indicates the lock status.
> - */
> -void __ice_q_vector_set_napi_queues(struct ice_q_vector *q_vector, bool locked)
> -{
> -	struct ice_rx_ring *rx_ring;
> -	struct ice_tx_ring *tx_ring;
> -
> -	ice_for_each_rx_ring(rx_ring, q_vector->rx)
> -		__ice_queue_set_napi(q_vector->vsi->netdev, rx_ring->q_index,
> -				     NETDEV_QUEUE_TYPE_RX, &q_vector->napi,
> -				     locked);
> -
> -	ice_for_each_tx_ring(tx_ring, q_vector->tx)
> -		__ice_queue_set_napi(q_vector->vsi->netdev, tx_ring->q_index,
> -				     NETDEV_QUEUE_TYPE_TX, &q_vector->napi,
> -				     locked);
> +	ice_for_each_txq(vsi, q_idx)
> +		netif_queue_set_napi(netdev, q_idx, NETDEV_QUEUE_TYPE_TX,
> +				     &vsi->tx_rings[q_idx]->q_vector->napi);
>  	/* Also set the interrupt number for the NAPI */
> -	netif_napi_set_irq(&q_vector->napi, q_vector->irq.virq);
> -}
> -
> -/**
> - * ice_q_vector_set_napi_queues - Map queue[s] associated with the napi
> - * @q_vector: q_vector pointer
> - *
> - * Associate the q_vector napi with all the queue[s] on the vector
> - */
> -void ice_q_vector_set_napi_queues(struct ice_q_vector *q_vector)
> -{
> -	struct ice_rx_ring *rx_ring;
> -	struct ice_tx_ring *tx_ring;
> -
> -	ice_for_each_rx_ring(rx_ring, q_vector->rx)
> -		ice_queue_set_napi(q_vector->vsi, rx_ring->q_index,
> -				   NETDEV_QUEUE_TYPE_RX, &q_vector->napi);
> +	ice_for_each_q_vector(vsi, v_idx) {
> +		struct ice_q_vector *q_vector = vsi->q_vectors[v_idx];
>  
> -	ice_for_each_tx_ring(tx_ring, q_vector->tx)
> -		ice_queue_set_napi(q_vector->vsi, tx_ring->q_index,
> -				   NETDEV_QUEUE_TYPE_TX, &q_vector->napi);
> -	/* Also set the interrupt number for the NAPI */
> -	netif_napi_set_irq(&q_vector->napi, q_vector->irq.virq);
> +		netif_napi_set_irq(&q_vector->napi, q_vector->irq.virq);
> +	}
>  }
>  
>  /**
> - * ice_vsi_set_napi_queues
> + * ice_vsi_clear_napi_queues
>   * @vsi: VSI pointer
>   *
> - * Associate queue[s] with napi for all vectors
> + * Clear the association between all VSI queues queue[s] and napi.
> + * The caller must hold rtnl_lock.
>   */
> -void ice_vsi_set_napi_queues(struct ice_vsi *vsi)
> +void ice_vsi_clear_napi_queues(struct ice_vsi *vsi)
>  {
> -	int i;
> +	struct net_device *netdev = vsi->netdev;
> +	int q_idx;
>  
> -	if (!vsi->netdev)
> +	if (!netdev)
>  		return;
>  
> -	ice_for_each_q_vector(vsi, i)
> -		ice_q_vector_set_napi_queues(vsi->q_vectors[i]);
> +	ice_for_each_txq(vsi, q_idx)
> +		netif_queue_set_napi(netdev, q_idx, NETDEV_QUEUE_TYPE_TX, NULL);
> +
> +	ice_for_each_rxq(vsi, q_idx)
> +		netif_queue_set_napi(netdev, q_idx, NETDEV_QUEUE_TYPE_RX, NULL);
>  }
>  
>  /**
> diff --git a/drivers/net/ethernet/intel/ice/ice_lib.h b/drivers/net/ethernet/intel/ice/ice_lib.h
> index 94ce8964dda6..36d86535695d 100644
> --- a/drivers/net/ethernet/intel/ice/ice_lib.h
> +++ b/drivers/net/ethernet/intel/ice/ice_lib.h
> @@ -44,16 +44,10 @@ void ice_vsi_cfg_netdev_tc(struct ice_vsi *vsi, u8 ena_tc);
>  struct ice_vsi *
>  ice_vsi_setup(struct ice_pf *pf, struct ice_vsi_cfg_params *params);
>  
> -void
> -ice_queue_set_napi(struct ice_vsi *vsi, unsigned int queue_index,
> -		   enum netdev_queue_type type, struct napi_struct *napi);
> -
> -void __ice_q_vector_set_napi_queues(struct ice_q_vector *q_vector, bool locked);
> -
> -void ice_q_vector_set_napi_queues(struct ice_q_vector *q_vector);
> -
>  void ice_vsi_set_napi_queues(struct ice_vsi *vsi);
>  
> +void ice_vsi_clear_napi_queues(struct ice_vsi *vsi);
> +
>  int ice_vsi_release(struct ice_vsi *vsi);
>  
>  void ice_vsi_close(struct ice_vsi *vsi);
> diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
> index 66820ed5e969..2d286a4609a5 100644
> --- a/drivers/net/ethernet/intel/ice/ice_main.c
> +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> @@ -3537,11 +3537,9 @@ static void ice_napi_add(struct ice_vsi *vsi)
>  	if (!vsi->netdev)
>  		return;
>  
> -	ice_for_each_q_vector(vsi, v_idx) {
> +	ice_for_each_q_vector(vsi, v_idx)
>  		netif_napi_add(vsi->netdev, &vsi->q_vectors[v_idx]->napi,
>  			       ice_napi_poll);
> -		__ice_q_vector_set_napi_queues(vsi->q_vectors[v_idx], false);
> -	}
>  }
>  
>  /**
> @@ -5519,7 +5517,9 @@ static int ice_reinit_interrupt_scheme(struct ice_pf *pf)
>  		if (ret)
>  			goto err_reinit;
>  		ice_vsi_map_rings_to_vectors(pf->vsi[v]);
> +		rtnl_lock();
>  		ice_vsi_set_napi_queues(pf->vsi[v]);
> +		rtnl_unlock();
>  	}
>  
>  	ret = ice_req_irq_msix_misc(pf);
> @@ -5533,8 +5533,12 @@ static int ice_reinit_interrupt_scheme(struct ice_pf *pf)
>  
>  err_reinit:
>  	while (v--)
> -		if (pf->vsi[v])
> +		if (pf->vsi[v]) {
> +			rtnl_lock();
> +			ice_vsi_clear_napi_queues(pf->vsi[v]);
> +			rtnl_unlock();
>  			ice_vsi_free_q_vectors(pf->vsi[v]);
> +		}
>  
>  	return ret;
>  }
> @@ -5599,6 +5603,9 @@ static int ice_suspend(struct device *dev)
>  	ice_for_each_vsi(pf, v) {
>  		if (!pf->vsi[v])
>  			continue;
> +		rtnl_lock();
> +		ice_vsi_clear_napi_queues(pf->vsi[v]);
> +		rtnl_unlock();
>  		ice_vsi_free_q_vectors(pf->vsi[v]);
>  	}
>  	ice_clear_interrupt_scheme(pf);
> @@ -7434,6 +7441,8 @@ int ice_vsi_open(struct ice_vsi *vsi)
>  		err = netif_set_real_num_rx_queues(vsi->netdev, vsi->num_rxq);
>  		if (err)
>  			goto err_set_qs;
> +
> +		ice_vsi_set_napi_queues(vsi);
>  	}
>  
>  	err = ice_up_complete(vsi);
> -- 
> 2.43.0
>