> From: Intel-wired-lan <intel-wired-lan-boun...@osuosl.org> On Behalf Of
> Francesco Ruggeri
> Sent: Thursday, July 2, 2020 3:39 PM
> To: linux-kernel@vger.kernel.org; net...@vger.kernel.org; intel-wired-
> l...@lists.osuosl.org; k...@kernel.org; da...@davemloft.net; Kirsher, Jeffrey
> T <jeffrey.t.kirs...@intel.com>; frugg...@arista.com
> Subject: [Intel-wired-lan] [PATCH v2] 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").
>
> v2: add fix for second race condition above.
>
> Signed-off-by: Francesco Ruggeri <frugg...@arista.com>
>
> ---
> drivers/net/ethernet/intel/igb/igb_main.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
Tested-by: Aaron Brown <aaron.f.br...@intel.com>
