From: Alex Dvoretsky Date: Thu, 12 Mar 2026 13:52:55 +0000 (+0100) Subject: igb: remove napi_synchronize() in igb_down() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1e067240379f950a0022208e0685f3465c211cb;p=thirdparty%2Fkernel%2Flinux.git igb: remove napi_synchronize() in igb_down() When an AF_XDP zero-copy application terminates abruptly (e.g., kill -9), the XSK buffer pool is destroyed but NAPI polling continues. igb_clean_rx_irq_zc() repeatedly returns the full budget, preventing napi_complete_done() from clearing NAPI_STATE_SCHED. igb_down() calls napi_synchronize() before napi_disable() for each queue vector. napi_synchronize() spins waiting for NAPI_STATE_SCHED to clear, which never happens. igb_down() blocks indefinitely, the TX watchdog fires, and the TX queue remains permanently stalled. napi_disable() already handles this correctly: it sets NAPI_STATE_DISABLE. After a full-budget poll, __napi_poll() checks napi_disable_pending(). If set, it forces completion and clears NAPI_STATE_SCHED, breaking the loop that napi_synchronize() cannot. napi_synchronize() was added in commit 41f149a285da ("igb: Fix possible panic caused by Rx traffic arrival while interface is down"). napi_disable() provides stronger guarantees: it prevents further scheduling and waits for any active poll to exit. Other Intel drivers (ixgbe, ice, i40e) use napi_disable() without a preceding napi_synchronize() in their down paths. Remove redundant napi_synchronize() call and reorder napi_disable() before igb_set_queue_napi() so the queue-to-NAPI mapping is only cleared after polling has fully stopped. Fixes: 2c6196013f84 ("igb: Add AF_XDP zero-copy Rx support") Cc: stable@vger.kernel.org Suggested-by: Maciej Fijalkowski Reviewed-by: Aleksandr Loktionov Signed-off-by: Alex Dvoretsky Reviewed-by: Maciej Fijalkowski Tested-by: Patryk Holda Signed-off-by: Tony Nguyen --- diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index ee99fd8fd513..ce91dda00ec0 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -2203,9 +2203,8 @@ void igb_down(struct igb_adapter *adapter) for (i = 0; i < adapter->num_q_vectors; i++) { if (adapter->q_vector[i]) { - napi_synchronize(&adapter->q_vector[i]->napi); - igb_set_queue_napi(adapter, i, NULL); napi_disable(&adapter->q_vector[i]->napi); + igb_set_queue_napi(adapter, i, NULL); } }