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Commit 025d0973 authored by Guilherme G. Piccoli's avatar Guilherme G. Piccoli Committed by David S. Miller
Browse files

cxgb4: avoid crash on PCI error recovery path 



During PCI error recovery process, specifically on eeh_err_detected()
we might have a NULL netdev struct, hence a direct dereference will
lead to a kernel oops. This was observed with latest upstream kernel
(v4.12-rc2) on Chelsio adapter T422-CR in PowerPC machines.

This patch checks for NULL pointer and avoids the crash, both in
eeh_err_detected() and eeh_resume(). Also, we avoid to trigger
a fatal error or to try disabling interrupts on FW during PCI
error recovery, because: (a) driver might not be able to accurately
access PCI regions in this case, and (b) trigger a fatal error
_during_ the recovery steps is a mistake that could prevent the
recovery path to complete successfully.

Reported-by: default avatarHarsha Thyagaraja <hathyaga@in.ibm.com>
Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 468b0df6

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

+13 −8
Original line number Diff line number Diff line
@@ -2771,6 +2771,9 @@ void t4_fatal_err(struct adapter *adap) 
{

	int port;



	if (pci_channel_offline(adap->pdev))

		return;



	/* Disable the SGE since ULDs are going to free resources that

	 * could be exposed to the adapter.  RDMA MWs for example...

	 */
@@ -3882,10 +3885,11 @@ static pci_ers_result_t eeh_err_detected(struct pci_dev *pdev, 
	spin_lock(&adap->stats_lock);

	for_each_port(adap, i) {

		struct net_device *dev = adap->port[i];



		if (dev) {

			netif_device_detach(dev);

			netif_carrier_off(dev);

		}

	}

	spin_unlock(&adap->stats_lock);

	disable_interrupts(adap);

	if (adap->flags & FULL_INIT_DONE)
@@ -3963,13 +3967,14 @@ static void eeh_resume(struct pci_dev *pdev) 
	rtnl_lock();

	for_each_port(adap, i) {

		struct net_device *dev = adap->port[i];



		if (dev) {

			if (netif_running(dev)) {

				link_start(dev);

				cxgb_set_rxmode(dev);

			}

			netif_device_attach(dev);

		}

	}

	rtnl_unlock();

}

drivers/net/ethernet/chelsio/cxgb4/t4_hw.c

+7 −2
Original line number Diff line number Diff line
@@ -4557,8 +4557,13 @@ void t4_intr_enable(struct adapter *adapter) 
 */

void t4_intr_disable(struct adapter *adapter)

{

	u32 whoami = t4_read_reg(adapter, PL_WHOAMI_A);

	u32 pf = CHELSIO_CHIP_VERSION(adapter->params.chip) <= CHELSIO_T5 ?

	u32 whoami, pf;



	if (pci_channel_offline(adapter->pdev))

		return;



	whoami = t4_read_reg(adapter, PL_WHOAMI_A);

	pf = CHELSIO_CHIP_VERSION(adapter->params.chip) <= CHELSIO_T5 ?

			SOURCEPF_G(whoami) : T6_SOURCEPF_G(whoami);



	t4_write_reg(adapter, MYPF_REG(PL_PF_INT_ENABLE_A), 0);