[PATCH] igb: fix hang issue of AER error during resume

[Aaron Ma]

PCIe AER error_detected caused a race issue with igb_resume.
Protect error_detected when igb is in down state.

Error logs:
kernel: igb 0000:02:00.0: disabling already-disabled device
kernel: WARNING: CPU: 0 PID: 277 at drivers/pci/pci.c:2248 pci_disable_device+0xc4/0xf0
kernel: RIP: 0010:pci_disable_device+0xc4/0xf0
kernel: Call Trace:
kernel:  <TASK>
kernel:  igb_io_error_detected+0x3e/0x60
kernel:  report_error_detected+0xd6/0x1c0
kernel:  ? __pfx_report_normal_detected+0x10/0x10
kernel:  report_normal_detected+0x16/0x30
kernel:  pci_walk_bus+0x74/0xa0
kernel:  pcie_do_recovery+0xb9/0x340
kernel:  ? __pfx_aer_root_reset+0x10/0x10
kernel:  aer_process_err_devices+0x168/0x220
kernel:  aer_isr+0x1b5/0x1e0
kernel:  ? __pfx_irq_thread_fn+0x10/0x10
kernel:  irq_thread_fn+0x21/0x70
kernel:  irq_thread+0xf8/0x1c0
kernel:  ? __pfx_irq_thread_dtor+0x10/0x10
kernel:  ? __pfx_irq_thread+0x10/0x10
kernel:  kthread+0xef/0x120
kernel:  ? __pfx_kthread+0x10/0x10
kernel:  ret_from_fork+0x29/0x50
kernel:  </TASK>
kernel: ---[ end trace 0000000000000000 ]---

Link: https://bugzilla.kernel.org/show_bug.cgi?id=217446
Signed-off-by: Aaron Ma <aaron.ma@xxxxxxxxxxxxx>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 58872a4c2540..8333d4ac8169 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -9581,14 +9581,21 @@ static pci_ers_result_t igb_io_error_detected(struct pci_dev *pdev,
 	struct net_device *netdev = pci_get_drvdata(pdev);
 	struct igb_adapter *adapter = netdev_priv(netdev);
 
+	if (test_bit(__IGB_DOWN, &adapter->state))
+		return PCI_ERS_RESULT_DISCONNECT;
+
+	rtnl_lock();
 	netif_device_detach(netdev);
 
-	if (state == pci_channel_io_perm_failure)
+	if (state == pci_channel_io_perm_failure) {
+		rtnl_unlock();
 		return PCI_ERS_RESULT_DISCONNECT;
+	}
 
 	if (netif_running(netdev))
 		igb_down(adapter);
 	pci_disable_device(pdev);
+	rtnl_unlock();
 
 	/* Request a slot reset. */
 	return PCI_ERS_RESULT_NEED_RESET;
-- 
2.34.1