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SubjectRe: [PATCH v2] sfc: potential dereference null pointer of rx_queue->page_ring
On Fri, Dec 17, 2021 at 04:33:58PM +0800, Jiasheng Jiang wrote:
> The return value of kcalloc() needs to be checked.

Your predicate is wrong. The code that uses rx_queue->page_ring
can deal with it being NULL.
The only thing you might want to do is set rx_queue->page_ptr_mask
to 0.

Martin

> To avoid dereference of null pointer in case of the failure of alloc.
> Therefore, it might be better to change the return type of
> efx_init_rx_recycle_ring(), efx_init_rx_queue(), efx_start_channels(),
> efx_start_datapath() and efx_start_all(), and return -ENOMEM when alloc
> fails and return 0 the others.
> Also, efx_net_open(), efx_pm_thaw(), efx_realloc_channels(),
> efx_reset_up() and efx_change_mtu() should deal with the return value of
> efx_start_all().
> By the way, I have no idea where the code come from, which does not
> mention in the commit message.
> But I find the same bug in another two places in the ethernet and I will
> then commit the patches to repair them.
> The Fixes tag below is the one I guess.
>
> Fixes: 5a6681e22c14 ("sfc: separate out SFC4000 ("Falcon") support into new sfc-falcon driver")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> ---
> Changelog:
>
> v1 -> v2
>
> *Change 1. Casade return -ENOMEM when alloc fails and deal with the
> error.
> ---
> drivers/net/ethernet/sfc/ef100_netdev.c | 4 +++-
> drivers/net/ethernet/sfc/efx.c | 9 ++++++--
> drivers/net/ethernet/sfc/efx_channels.c | 14 ++++++++++---
> drivers/net/ethernet/sfc/efx_channels.h | 2 +-
> drivers/net/ethernet/sfc/efx_common.c | 28 ++++++++++++++++++-------
> drivers/net/ethernet/sfc/efx_common.h | 2 +-
> drivers/net/ethernet/sfc/rx_common.c | 14 ++++++++++---
> drivers/net/ethernet/sfc/rx_common.h | 2 +-
> 8 files changed, 56 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/net/ethernet/sfc/ef100_netdev.c b/drivers/net/ethernet/sfc/ef100_netdev.c
> index 67fe44db6b61..aaba36e40446 100644
> --- a/drivers/net/ethernet/sfc/ef100_netdev.c
> +++ b/drivers/net/ethernet/sfc/ef100_netdev.c
> @@ -162,7 +162,9 @@ static int ef100_net_open(struct net_device *net_dev)
> if (rc)
> goto fail;
>
> - efx_start_all(efx);
> + rc = efx_start_all(efx);
> + if (rc)
> + goto fail;
>
> /* Link state detection is normally event-driven; we have
> * to poll now because we could have missed a change
> diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
> index c746ca7235f1..874301cda686 100644
> --- a/drivers/net/ethernet/sfc/efx.c
> +++ b/drivers/net/ethernet/sfc/efx.c
> @@ -540,7 +540,10 @@ int efx_net_open(struct net_device *net_dev)
> * before the monitor starts running */
> efx_link_status_changed(efx);
>
> - efx_start_all(efx);
> + rc = efx_start_all(efx);
> + if (rc)
> + return rc;
> +
> if (efx->state == STATE_DISABLED || efx->reset_pending)
> netif_device_detach(efx->net_dev);
> efx_selftest_async_start(efx);
> @@ -1224,7 +1227,9 @@ static int efx_pm_thaw(struct device *dev)
> efx_mcdi_port_reconfigure(efx);
> mutex_unlock(&efx->mac_lock);
>
> - efx_start_all(efx);
> + rc = efx_start_all(efx);
> + if (rc)
> + goto fail;
>
> efx_device_attach_if_not_resetting(efx);
>
> diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c
> index bb48a139dd15..451f7c6a7680 100644
> --- a/drivers/net/ethernet/sfc/efx_channels.c
> +++ b/drivers/net/ethernet/sfc/efx_channels.c
> @@ -837,7 +837,10 @@ int efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries)
> "unable to restart interrupts on channel reallocation\n");
> efx_schedule_reset(efx, RESET_TYPE_DISABLE);
> } else {
> - efx_start_all(efx);
> + rc = efx_start_all(efx);
> + if (rc)
> + goto rollback;
> +
> efx_device_attach_if_not_resetting(efx);
> }
> return rc;
> @@ -1055,11 +1058,12 @@ void efx_disable_interrupts(struct efx_nic *efx)
> efx->type->irq_disable_non_ev(efx);
> }
>
> -void efx_start_channels(struct efx_nic *efx)
> +int efx_start_channels(struct efx_nic *efx)
> {
> struct efx_tx_queue *tx_queue;
> struct efx_rx_queue *rx_queue;
> struct efx_channel *channel;
> + int ret;
>
> efx_for_each_channel(channel, efx) {
> efx_for_each_channel_tx_queue(tx_queue, channel) {
> @@ -1068,7 +1072,10 @@ void efx_start_channels(struct efx_nic *efx)
> }
>
> efx_for_each_channel_rx_queue(rx_queue, channel) {
> - efx_init_rx_queue(rx_queue);
> + ret = efx_init_rx_queue(rx_queue);
> + if (ret)
> + return ret;
> +
> atomic_inc(&efx->active_queues);
> efx_stop_eventq(channel);
> efx_fast_push_rx_descriptors(rx_queue, false);
> @@ -1077,6 +1084,7 @@ void efx_start_channels(struct efx_nic *efx)
>
> WARN_ON(channel->rx_pkt_n_frags);
> }
> + return 0;
> }
>
> void efx_stop_channels(struct efx_nic *efx)
> diff --git a/drivers/net/ethernet/sfc/efx_channels.h b/drivers/net/ethernet/sfc/efx_channels.h
> index d77ec1f77fb1..da38b6be5a45 100644
> --- a/drivers/net/ethernet/sfc/efx_channels.h
> +++ b/drivers/net/ethernet/sfc/efx_channels.h
> @@ -42,7 +42,7 @@ void efx_remove_channel(struct efx_channel *channel);
> void efx_remove_channels(struct efx_nic *efx);
> void efx_fini_channels(struct efx_nic *efx);
> struct efx_channel *efx_copy_channel(const struct efx_channel *old_channel);
> -void efx_start_channels(struct efx_nic *efx);
> +int efx_start_channels(struct efx_nic *efx);
> void efx_stop_channels(struct efx_nic *efx);
>
> void efx_init_napi_channel(struct efx_channel *channel);
> diff --git a/drivers/net/ethernet/sfc/efx_common.c b/drivers/net/ethernet/sfc/efx_common.c
> index de797e1ac5a9..0b5fec7769ea 100644
> --- a/drivers/net/ethernet/sfc/efx_common.c
> +++ b/drivers/net/ethernet/sfc/efx_common.c
> @@ -309,7 +309,10 @@ int efx_change_mtu(struct net_device *net_dev, int new_mtu)
> efx_mac_reconfigure(efx, true);
> mutex_unlock(&efx->mac_lock);
>
> - efx_start_all(efx);
> + rc = efx_start_all(efx);
> + if (rc)
> + return rc;
> +
> efx_device_attach_if_not_resetting(efx);
> return 0;
> }
> @@ -361,11 +364,12 @@ void efx_start_monitor(struct efx_nic *efx)
> * to propagate configuration changes (mtu, checksum offload), or
> * to clear hardware error conditions
> */
> -static void efx_start_datapath(struct efx_nic *efx)
> +static int efx_start_datapath(struct efx_nic *efx)
> {
> netdev_features_t old_features = efx->net_dev->features;
> bool old_rx_scatter = efx->rx_scatter;
> size_t rx_buf_len;
> + int ret;
>
> /* Calculate the rx buffer allocation parameters required to
> * support the current MTU, including padding for header
> @@ -431,12 +435,15 @@ static void efx_start_datapath(struct efx_nic *efx)
> efx->txq_wake_thresh = efx->txq_stop_thresh / 2;
>
> /* Initialise the channels */
> - efx_start_channels(efx);
> + ret = efx_start_channels(efx);
> + if (ret)
> + return ret;
>
> efx_ptp_start_datapath(efx);
>
> if (netif_device_present(efx->net_dev))
> netif_tx_wake_all_queues(efx->net_dev);
> + return 0;
> }
>
> static void efx_stop_datapath(struct efx_nic *efx)
> @@ -524,8 +531,9 @@ static void efx_stop_port(struct efx_nic *efx)
> * is safe to call multiple times, so long as the NIC is not disabled.
> * Requires the RTNL lock.
> */
> -void efx_start_all(struct efx_nic *efx)
> +int efx_start_all(struct efx_nic *efx)
> {
> + int ret;
> EFX_ASSERT_RESET_SERIALISED(efx);
> BUG_ON(efx->state == STATE_DISABLED);
>
> @@ -534,10 +542,12 @@ void efx_start_all(struct efx_nic *efx)
> */
> if (efx->port_enabled || !netif_running(efx->net_dev) ||
> efx->reset_pending)
> - return;
> + return 0;
>
> efx_start_port(efx);
> - efx_start_datapath(efx);
> + ret = efx_start_datapath(efx);
> + if (ret)
> + return ret;
>
> /* Start the hardware monitor if there is one */
> efx_start_monitor(efx);
> @@ -557,6 +567,8 @@ void efx_start_all(struct efx_nic *efx)
> efx->type->update_stats(efx, NULL, NULL);
> spin_unlock_bh(&efx->stats_lock);
> }
> +
> + return 0;
> }
>
> /* Quiesce the hardware and software data path, and regular activity
> @@ -786,7 +798,9 @@ int efx_reset_up(struct efx_nic *efx, enum reset_type method, bool ok)
>
> mutex_unlock(&efx->mac_lock);
>
> - efx_start_all(efx);
> + rc = efx_start_all(efx);
> + if (rc)
> + goto fail;
>
> if (efx->type->udp_tnl_push_ports)
> efx->type->udp_tnl_push_ports(efx);
> diff --git a/drivers/net/ethernet/sfc/efx_common.h b/drivers/net/ethernet/sfc/efx_common.h
> index 65513fd0cf6c..adf84a64760b 100644
> --- a/drivers/net/ethernet/sfc/efx_common.h
> +++ b/drivers/net/ethernet/sfc/efx_common.h
> @@ -28,7 +28,7 @@ void efx_fini_struct(struct efx_nic *efx);
> void efx_link_clear_advertising(struct efx_nic *efx);
> void efx_link_set_wanted_fc(struct efx_nic *efx, u8);
>
> -void efx_start_all(struct efx_nic *efx);
> +int efx_start_all(struct efx_nic *efx);
> void efx_stop_all(struct efx_nic *efx);
>
> void efx_net_stats(struct net_device *net_dev, struct rtnl_link_stats64 *stats);
> diff --git a/drivers/net/ethernet/sfc/rx_common.c b/drivers/net/ethernet/sfc/rx_common.c
> index 68fc7d317693..b7d974e25a43 100644
> --- a/drivers/net/ethernet/sfc/rx_common.c
> +++ b/drivers/net/ethernet/sfc/rx_common.c
> @@ -131,7 +131,7 @@ void efx_discard_rx_packet(struct efx_channel *channel,
> efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
> }
>
> -static void efx_init_rx_recycle_ring(struct efx_rx_queue *rx_queue)
> +static int efx_init_rx_recycle_ring(struct efx_rx_queue *rx_queue)
> {
> unsigned int bufs_in_recycle_ring, page_ring_size;
> struct efx_nic *efx = rx_queue->efx;
> @@ -150,7 +150,11 @@ static void efx_init_rx_recycle_ring(struct efx_rx_queue *rx_queue)
> efx->rx_bufs_per_page);
> rx_queue->page_ring = kcalloc(page_ring_size,
> sizeof(*rx_queue->page_ring), GFP_KERNEL);
> + if (!rx_queue->page_ring)
> + return -ENOMEM;
> +
> rx_queue->page_ptr_mask = page_ring_size - 1;
> + return 0;
> }
>
> static void efx_fini_rx_recycle_ring(struct efx_rx_queue *rx_queue)
> @@ -222,7 +226,7 @@ int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
> return rc;
> }
>
> -void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
> +int efx_init_rx_queue(struct efx_rx_queue *rx_queue)
> {
> unsigned int max_fill, trigger, max_trigger;
> struct efx_nic *efx = rx_queue->efx;
> @@ -236,7 +240,9 @@ void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
> rx_queue->notified_count = 0;
> rx_queue->removed_count = 0;
> rx_queue->min_fill = -1U;
> - efx_init_rx_recycle_ring(rx_queue);
> + rc = efx_init_rx_recycle_ring(rx_queue);
> + if (rc)
> + return rc;
>
> rx_queue->page_remove = 0;
> rx_queue->page_add = rx_queue->page_ptr_mask + 1;
> @@ -275,6 +281,8 @@ void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
>
> /* Set up RX descriptor ring */
> efx_nic_init_rx(rx_queue);
> +
> + return 0;
> }
>
> void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
> diff --git a/drivers/net/ethernet/sfc/rx_common.h b/drivers/net/ethernet/sfc/rx_common.h
> index 207ccd8ba062..16133d3f46b2 100644
> --- a/drivers/net/ethernet/sfc/rx_common.h
> +++ b/drivers/net/ethernet/sfc/rx_common.h
> @@ -47,7 +47,7 @@ void efx_discard_rx_packet(struct efx_channel *channel,
> unsigned int n_frags);
>
> int efx_probe_rx_queue(struct efx_rx_queue *rx_queue);
> -void efx_init_rx_queue(struct efx_rx_queue *rx_queue);
> +int efx_init_rx_queue(struct efx_rx_queue *rx_queue);
> void efx_fini_rx_queue(struct efx_rx_queue *rx_queue);
> void efx_remove_rx_queue(struct efx_rx_queue *rx_queue);
> void efx_destroy_rx_queue(struct efx_rx_queue *rx_queue);
> --
> 2.25.1

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