From: Alexander Duyck fbn->num_napi is the count of live napi vectors, each of which owns an IRQ. The PM path had freed them without clearing the count. fbnic_pm_suspend() tears the datapath down via ndo_stop() and frees the IRQs, but leaves netif_running() true so resume knows to re-open. Resume rebuilds the datapath in __fbnic_pm_resume() and fbnic_reset_queues() sets num_napi and __fbnic_open() re-allocates the vectors. When the datapath is torn down but never rebuilt, num_napi is left pointing at freed vectors under 2 different scenarios: - a PCIe error recovery that fails (fbnic_err_slot_reset() -> __fbnic_pm_resume() returns an error -> PCI_ERS_RESULT_DISCONNECT), so .resume never runs; or - an __fbnic_open() that fails partway on resume and unwinds, freeing the vectors after fbnic_reset_queues() has already set num_napi. The netdev is then running with num_napi > 0 but napi[] freed, and the eventual remove/unbind close re-enters fbnic_down() -> fbnic_dbg_down() and dereferences the freed vectors: BUG: kernel NULL pointer dereference, address: 0000000000000210 RIP: fbnic_dbg_down+0x28 Clear num_napi when the vectors are freed: in the suspend teardown (a good resume re-establishes it before __fbnic_open()) and on the resume open failure. A redundant ndo_stop() then walks an empty napi[]. The normal ndo_stop() down/up cycle is untouched and keeps num_napi for the next ndo_open(). Fixes: bc6107771bb4 ("eth: fbnic: Allocate a netdevice and napi vectors with queues") Signed-off-by: Alexander Duyck --- drivers/net/ethernet/meta/fbnic/fbnic_pci.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_pci.c b/drivers/net/ethernet/meta/fbnic/fbnic_pci.c index 8b9bc9e8ea56..c6698e3002a1 100644 --- a/drivers/net/ethernet/meta/fbnic/fbnic_pci.c +++ b/drivers/net/ethernet/meta/fbnic/fbnic_pci.c @@ -434,6 +434,7 @@ static int fbnic_pm_suspend(struct device *dev) { struct fbnic_dev *fbd = dev_get_drvdata(dev); struct net_device *netdev = fbd->netdev; + struct fbnic_net *fbn; if (fbnic_init_failure(fbd)) goto null_uc_addr; @@ -441,11 +442,16 @@ static int fbnic_pm_suspend(struct device *dev) rtnl_lock(); netdev_lock(netdev); + fbn = netdev_priv(netdev); + netif_device_detach(netdev); if (netif_running(netdev)) netdev->netdev_ops->ndo_stop(netdev); + /* The IRQs are about to be freed, so drop the napi vector count */ + fbn->num_napi = 0; + netdev_unlock(netdev); rtnl_unlock(); @@ -508,16 +514,20 @@ static int __fbnic_pm_resume(struct device *dev) if (fbnic_init_failure(fbd)) return 0; + rtnl_lock(); + netdev_lock(netdev); + fbn = netdev_priv(netdev); /* Reset the queues if needed */ fbnic_reset_queues(fbn, fbn->num_tx_queues, fbn->num_rx_queues); - rtnl_lock(); - netdev_lock(netdev); - - if (netif_running(netdev)) + if (netif_running(netdev)) { err = __fbnic_open(fbn); + /* On failure the vectors are freed, so drop the count */ + if (err) + fbn->num_napi = 0; + } netdev_unlock(netdev); rtnl_unlock();