[PATCH AUTOSEL for 4.14 073/135] liquidio: fix kernel panic in VF driver

From: alexander . levin
Date: Thu Dec 07 2017 - 13:01:35 EST


From: Felix Manlunas <felix.manlunas@xxxxxxxxxx>

[ Upstream commit aa28667cfbe4ff6f14454dda210b1f2e485f99b5 ]

Doing ifconfig down on VF driver in the middle of receiving line rate
traffic causes a kernel panic:

LiquidIO_VF 0000:02:00.3: should not come here should not get rx when poll mode = 0 for vf
BUG: unable to handle kernel NULL pointer dereference at (null)
.
.
.
Call Trace:
<IRQ>
? tasklet_action+0x102/0x120
__do_softirq+0x91/0x292
irq_exit+0xb6/0xc0
do_IRQ+0x4f/0xd0
common_interrupt+0x93/0x93
</IRQ>
RIP: 0010:cpuidle_enter_state+0x142/0x2f0
RSP: 0018:ffffffffa6403e20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff59
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 000000000000001f
RDX: 0000000000000000 RSI: 000000002ab7519f RDI: 0000000000000000
RBP: ffffffffa6403e58 R08: 0000000000000084 R09: 0000000000000018
R10: ffffffffa6403df0 R11: 00000000000003c7 R12: 0000000000000003
R13: ffffd27ebd806800 R14: ffffffffa64d40d8 R15: 0000007be072823f
cpuidle_enter+0x17/0x20
call_cpuidle+0x23/0x40
do_idle+0x18c/0x1f0
cpu_startup_entry+0x64/0x70
rest_init+0xa5/0xb0
start_kernel+0x45e/0x46b
x86_64_start_reservations+0x24/0x26
x86_64_start_kernel+0x6f/0x72
secondary_startup_64+0xa5/0xa5
Code: Bad RIP value.
RIP: (null) RSP: ffff9246ed003f28
CR2: 0000000000000000
---[ end trace 92731e80f31b7d7d ]---
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: 0x24000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
---[ end Kernel panic - not syncing: Fatal exception in interrupt

Reason is: in the function assigned to net_device_ops->ndo_stop, the steps
for bringing down the interface are done in the wrong order. The step that
notifies the NIC firmware to stop forwarding packets to host is done too
late. Fix it by moving that step to the beginning.

Signed-off-by: Felix Manlunas <felix.manlunas@xxxxxxxxxx>
Signed-off-by: Raghu Vatsavayi <raghu.vatsavayi@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
drivers/net/ethernet/cavium/liquidio/lio_vf_main.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
index 2e993ce43b66..4d2db22e011b 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
@@ -1289,6 +1289,9 @@ static int liquidio_stop(struct net_device *netdev)
struct octeon_device *oct = lio->oct_dev;
struct napi_struct *napi, *n;

+ /* tell Octeon to stop forwarding packets to host */
+ send_rx_ctrl_cmd(lio, 0);
+
if (oct->props[lio->ifidx].napi_enabled) {
list_for_each_entry_safe(napi, n, &netdev->napi_list, dev_list)
napi_disable(napi);
@@ -1306,9 +1309,6 @@ static int liquidio_stop(struct net_device *netdev)
netif_carrier_off(netdev);
lio->link_changes++;

- /* tell Octeon to stop forwarding packets to host */
- send_rx_ctrl_cmd(lio, 0);
-
ifstate_reset(lio, LIO_IFSTATE_RUNNING);

txqs_stop(netdev);
--
2.11.0