From 024a8168b749db7a4aa40a5fbdfa04bf7e77c1c0 Mon Sep 17 00:00:00 2001 From: Francesco Ruggeri Date: Thu, 2 Jul 2020 15:39:06 -0700 Subject: [PATCH] igb: reinit_locked() should be called with rtnl_lock We observed two panics involving races with igb_reset_task. The first panic is caused by this race condition: kworker reboot -f igb_reset_task igb_reinit_locked igb_down napi_synchronize __igb_shutdown igb_clear_interrupt_scheme igb_free_q_vectors igb_free_q_vector adapter->q_vector[v_idx] = NULL; napi_disable Panics trying to access adapter->q_vector[v_idx].napi_state The second panic (a divide error) is caused by this race: kworker reboot -f tx packet igb_reset_task __igb_shutdown rtnl_lock() ... igb_clear_interrupt_scheme igb_free_q_vectors adapter->num_tx_queues = 0 ... rtnl_unlock() rtnl_lock() igb_reinit_locked igb_down igb_up netif_tx_start_all_queues dev_hard_start_xmit igb_xmit_frame igb_tx_queue_mapping Panics on r_idx % adapter->num_tx_queues This commit applies to igb_reset_task the same changes that were applied to ixgbe in commit 2f90b8657ec9 ("ixgbe: this patch adds support for DCB to the kernel and ixgbe driver"), commit 8f4c5c9fb87a ("ixgbe: reinit_locked() should be called with rtnl_lock") and commit 88adce4ea8f9 ("ixgbe: fix possible race in reset subtask"). Signed-off-by: Francesco Ruggeri Tested-by: Aaron Brown Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/igb/igb_main.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index 8bb3db2cbd41..6e5861bfb0fa 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -6224,9 +6224,18 @@ static void igb_reset_task(struct work_struct *work) struct igb_adapter *adapter; adapter = container_of(work, struct igb_adapter, reset_task); + rtnl_lock(); + /* If we're already down or resetting, just bail */ + if (test_bit(__IGB_DOWN, &adapter->state) || + test_bit(__IGB_RESETTING, &adapter->state)) { + rtnl_unlock(); + return; + } + igb_dump(adapter); netdev_err(adapter->netdev, "Reset adapter\n"); igb_reinit_locked(adapter); + rtnl_unlock(); } /**