diff options
| author | Firo Yang <firo.yang@suse.com> | 2020-02-12 06:09:17 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-12 09:43:26 -0800 |
| commit | 0f90522591fd09dd201065c53ebefdfe3c6b55cb (patch) | |
| tree | d1bd8c5f1a81e14db272a23e5192c0d6015d5f73 | |
| parent | b44beb8ae5d50b055b3df16fd5688c92d32f3773 (diff) | |
| download | linux-0f90522591fd09dd201065c53ebefdfe3c6b55cb.tar.gz | |
enic: prevent waking up stopped tx queues over watchdog reset
Recent months, our customer reported several kernel crashes all
preceding with following message:
NETDEV WATCHDOG: eth2 (enic): transmit queue 0 timed out
Error message of one of those crashes:
BUG: unable to handle kernel paging request at ffffffffa007e090
After analyzing severl vmcores, I found that most of crashes are
caused by memory corruption. And all the corrupted memory areas
are overwritten by data of network packets. Moreover, I also found
that the tx queues were enabled over watchdog reset.
After going through the source code, I found that in enic_stop(),
the tx queues stopped by netif_tx_disable() could be woken up over
a small time window between netif_tx_disable() and the
napi_disable() by the following code path:
napi_poll->
enic_poll_msix_wq->
vnic_cq_service->
enic_wq_service->
netif_wake_subqueue(enic->netdev, q_number)->
test_and_clear_bit(__QUEUE_STATE_DRV_XOFF, &txq->state)
In turn, upper netowrk stack could queue skb to ENIC NIC though
enic_hard_start_xmit(). And this might introduce some race condition.
Our customer comfirmed that this kind of kernel crash doesn't occur over
90 days since they applied this patch.
Signed-off-by: Firo Yang <firo.yang@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/ethernet/cisco/enic/enic_main.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c index bbd7b3175f09..ddf60dc9ad16 100644 --- a/drivers/net/ethernet/cisco/enic/enic_main.c +++ b/drivers/net/ethernet/cisco/enic/enic_main.c @@ -2013,10 +2013,10 @@ static int enic_stop(struct net_device *netdev) napi_disable(&enic->napi[i]); netif_carrier_off(netdev); - netif_tx_disable(netdev); if (vnic_dev_get_intr_mode(enic->vdev) == VNIC_DEV_INTR_MODE_MSIX) for (i = 0; i < enic->wq_count; i++) napi_disable(&enic->napi[enic_cq_wq(enic, i)]); + netif_tx_disable(netdev); if (!enic_is_dynamic(enic) && !enic_is_sriov_vf(enic)) enic_dev_del_station_addr(enic); |