Re: [PATCH net] igc: remove napi_synchronize() in igc_down()
From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Date: 2026-07-13 09:42:53
Also in:
intel-wired-lan, stable
On Sun, Jul 12, 2026 at 02:22:42PM +0100, David Carlier wrote:
When an AF_XDP zero-copy application is killed abruptly, the XSK pool is
torn down but NAPI keeps polling. igc_clean_rx_irq_zc() then returns the
full budget on every poll, so napi_complete_done() never clears
NAPI_STATE_SCHED.
igc_down() calls napi_synchronize() before napi_disable(), so it spins
forever waiting for that bit and the interface never goes down. Drop the
napi_synchronize() and let napi_disable() do the job -- it sets
NAPI_STATE_DISABLE, which forces the stuck poll to complete. Reorder it
ahead of igc_set_queue_napi() so the NAPI mapping is cleared only after
polling has stopped, matching the recent igb fix b1e067240379.
Fixes: fc9df2a0b520 ("igc: Enable RX via AF_XDP zero-copy")
Suggested-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: David Carlier <redacted>Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> This is a mirror of what Alex Dvoretsky did on igb, correct? Did you reproduce the same issue on your side or is it a blind shot at this driver? Regardless, I think it's a correct thing to do, but some clarification would be nice.
quoted hunk ↗ jump to hunk
--- drivers/net/ethernet/intel/igc/igc_main.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 2c9e2dfd8499..b3883a5a7d7a 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c@@ -5352,9 +5352,8 @@ void igc_down(struct igc_adapter *adapter) for (i = 0; i < adapter->num_q_vectors; i++) { if (adapter->q_vector[i]) { - napi_synchronize(&adapter->q_vector[i]->napi); - igc_set_queue_napi(adapter, i, NULL); napi_disable(&adapter->q_vector[i]->napi); + igc_set_queue_napi(adapter, i, NULL); } }-- 2.53.0