From 63d4a4c145cca2e84dc6e62d2ef5cb990c9723c2 Mon Sep 17 00:00:00 2001 From: Shay Agroskin Date: Wed, 19 Aug 2020 20:28:36 +0300 Subject: [PATCH 1/3] net: ena: Prevent reset after device destruction The reset work is scheduled by the timer routine whenever it detects that a device reset is required (e.g. when a keep_alive signal is missing). When releasing device resources in ena_destroy_device() the driver cancels the scheduling of the timer routine without destroying the reset work explicitly. This creates the following bug: The driver is suspended and the ena_suspend() function is called -> This function calls ena_destroy_device() to free the net device resources -> The driver waits for the timer routine to finish its execution and then cancels it, thus preventing from it to be called again. If, in its final execution, the timer routine schedules a reset, the reset routine might be called afterwards,and a redundant call to ena_restore_device() would be made. By changing the reset routine we allow it to read the device's state accurately. This is achieved by checking whether ENA_FLAG_TRIGGER_RESET flag is set before resetting the device and making both the destruction function and the flag check are under rtnl lock. The ENA_FLAG_TRIGGER_RESET is cleared at the end of the destruction routine. Also surround the flag check with 'likely' because we expect that the reset routine would be called only when ENA_FLAG_TRIGGER_RESET flag is set. The destruction of the timer and reset services in __ena_shutoff() have to stay, even though the timer routine is destroyed in ena_destroy_device(). This is to avoid a case in which the reset routine is scheduled after free_netdev() in __ena_shutoff(), which would create an access to freed memory in adapter->flags. Fixes: 8c5c7abdeb2d ("net: ena: add power management ops to the ENA driver") Signed-off-by: Shay Agroskin Signed-off-by: David S. Miller --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index 2a6c9725e0922..44aeace196f07 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -3601,16 +3601,14 @@ static void ena_fw_reset_device(struct work_struct *work) { struct ena_adapter *adapter = container_of(work, struct ena_adapter, reset_task); - struct pci_dev *pdev = adapter->pdev; - if (unlikely(!test_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags))) { - dev_err(&pdev->dev, - "device reset schedule while reset bit is off\n"); - return; - } rtnl_lock(); - ena_destroy_device(adapter, false); - ena_restore_device(adapter); + + if (likely(test_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags))) { + ena_destroy_device(adapter, false); + ena_restore_device(adapter); + } + rtnl_unlock(); } @@ -4389,8 +4387,11 @@ static void __ena_shutoff(struct pci_dev *pdev, bool shutdown) netdev->rx_cpu_rmap = NULL; } #endif /* CONFIG_RFS_ACCEL */ - del_timer_sync(&adapter->timer_service); + /* Make sure timer and reset routine won't be called after + * freeing device resources. + */ + del_timer_sync(&adapter->timer_service); cancel_work_sync(&adapter->reset_task); rtnl_lock(); /* lock released inside the below if-else block */ From 8b147f6f3e7de4e51113e3e9ec44aa2debc02c58 Mon Sep 17 00:00:00 2001 From: Shay Agroskin Date: Wed, 19 Aug 2020 20:28:37 +0300 Subject: [PATCH 2/3] net: ena: Change WARN_ON expression in ena_del_napi_in_range() The ena_del_napi_in_range() function unregisters the napi handler for rings in a given range. This function had the following WARN_ON macro: WARN_ON(ENA_IS_XDP_INDEX(adapter, i) && adapter->ena_napi[i].xdp_ring); This macro prints the call stack if the expression inside of it is true [1], but the expression inside of it is the wanted situation. The expression checks whether the ring has an XDP queue and its index corresponds to a XDP one. This patch changes the expression to !ENA_IS_XDP_INDEX(adapter, i) && adapter->ena_napi[i].xdp_ring which indicates an unwanted situation. Also, change the structure of the function. The napi handler is unregistered for all rings, and so there's no need to check whether the index is an XDP index or not. By removing this check the code becomes much more readable. Fixes: 548c4940b9f1 ("net: ena: Implement XDP_TX action") Signed-off-by: Shay Agroskin Signed-off-by: David S. Miller --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index 44aeace196f07..233db15c970d6 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -2180,13 +2180,10 @@ static void ena_del_napi_in_range(struct ena_adapter *adapter, int i; for (i = first_index; i < first_index + count; i++) { - /* Check if napi was initialized before */ - if (!ENA_IS_XDP_INDEX(adapter, i) || - adapter->ena_napi[i].xdp_ring) - netif_napi_del(&adapter->ena_napi[i].napi); - else - WARN_ON(ENA_IS_XDP_INDEX(adapter, i) && - adapter->ena_napi[i].xdp_ring); + netif_napi_del(&adapter->ena_napi[i].napi); + + WARN_ON(!ENA_IS_XDP_INDEX(adapter, i) && + adapter->ena_napi[i].xdp_ring); } } From ccd143e5150f24b9ba15145c7221b61dd9e41021 Mon Sep 17 00:00:00 2001 From: Shay Agroskin Date: Wed, 19 Aug 2020 20:28:38 +0300 Subject: [PATCH 3/3] net: ena: Make missed_tx stat incremental Most statistics in ena driver are incremented, meaning that a stat's value is a sum of all increases done to it since driver/queue initialization. This patch makes all statistics this way, effectively making missed_tx statistic incremental. Also added a comment regarding rx_drops and tx_drops to make it clearer how these counters are calculated. Fixes: 11095fdb712b ("net: ena: add statistics for missed tx packets") Signed-off-by: Shay Agroskin Signed-off-by: David S. Miller --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index 233db15c970d6..a3a8edf9a734d 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -3687,7 +3687,7 @@ static int check_missing_comp_in_tx_queue(struct ena_adapter *adapter, } u64_stats_update_begin(&tx_ring->syncp); - tx_ring->tx_stats.missed_tx = missed_tx; + tx_ring->tx_stats.missed_tx += missed_tx; u64_stats_update_end(&tx_ring->syncp); return rc; @@ -4556,6 +4556,9 @@ static void ena_keep_alive_wd(void *adapter_data, tx_drops = ((u64)desc->tx_drops_high << 32) | desc->tx_drops_low; u64_stats_update_begin(&adapter->syncp); + /* These stats are accumulated by the device, so the counters indicate + * all drops since last reset. + */ adapter->dev_stats.rx_drops = rx_drops; adapter->dev_stats.tx_drops = tx_drops; u64_stats_update_end(&adapter->syncp);