[PATCH 6.7 28/61] idpf: disable local BH when scheduling napi for marker packets

Sasha Levin
2024-03-13T16:33:13Z

From: Emil Tantilov <emil.s.tantilov@intel.com>

[ Upstream commit 330068589389ccae3452db15ecacc3e147ac9c1c ]

Fix softirq's not being handled during napi_schedule() call when
receiving marker packets for queue disable by disabling local bottom
half.

The issue can be seen on ifdown:
NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!

Using ftrace to catch the failing scenario:
ifconfig [003] d.... 22739.830624: softirq_raise: vec=3 [action=NET_RX]
<idle>-0 [003] ..s.. 22739.831357: softirq_entry: vec=3 [action=NET_RX]

No interrupt and CPU is idle.

After the patch when disabling local BH before calling napi_schedule:
ifconfig [003] d.... 22993.928336: softirq_raise: vec=3 [action=NET_RX]
ifconfig [003] ..s1. 22993.928337: softirq_entry: vec=3 [action=NET_RX]

Fixes: c2d548cad150 ("idpf: add TX splitq napi poll support")
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Signed-off-by: Alan Brady <alan.brady@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/idpf/idpf_virtchnl.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
index 2c1b051fdc0d4..b0c52f17848f6 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
@@ -2087,8 +2087,10 @@ int idpf_send_disable_queues_msg(struct idpf_vport *vport)
set_bit(__IDPF_Q_POLL_MODE, vport->txqs[i]->flags);

/* schedule the napi to receive all the marker packets */
+ local_bh_disable();
for (i = 0; i < vport->num_q_vectors; i++)
napi_schedule(&vport->q_vectors[i].napi);
+ local_bh_enable();

return idpf_wait_for_marker_event(vport);
}
--
2.43.0