[PATCH net v2 09/12] i40e: Fix preempt count leak in napi poll tracepoint
From: Tony Nguyen <anthony.l.nguyen@intel.com>
Date: 2026-02-25 21:15:59
Also in:
intel-wired-lan
Subsystem:
intel ethernet drivers, networking drivers, the rest · Maintainers:
Tony Nguyen, Przemek Kitszel, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Thomas Gleixner <tglx@kernel.org>
Using get_cpu() in the tracepoint assignment causes an obvious preempt
count leak because nothing invokes put_cpu() to undo it:
softirq: huh, entered softirq 3 NET_RX with preempt_count 00000100, exited with 00000101?
This clearly has seen a lot of testing in the last 3+ years...
Use smp_processor_id() instead.
Fixes: 6d4d584a7ea8 ("i40e: Add i40e_napi_poll tracepoint")
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: intel-wired-lan@lists.osuosl.org
Cc: netdev@vger.kernel.org
Reviewed-by: Joe Damato <redacted>
Reviewed-by: Aleksandr Loktionov <redacted>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
drivers/net/ethernet/intel/i40e/i40e_trace.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_trace.h b/drivers/net/ethernet/intel/i40e/i40e_trace.h
index 759f3d1c4c8f..dde0ccd789ed 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_trace.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_trace.h@@ -88,7 +88,7 @@ TRACE_EVENT(i40e_napi_poll, __entry->rx_clean_complete = rx_clean_complete; __entry->tx_clean_complete = tx_clean_complete; __entry->irq_num = q->irq_num; - __entry->curr_cpu = get_cpu(); + __entry->curr_cpu = smp_processor_id(); __assign_str(qname); __assign_str(dev_name); __assign_bitmask(irq_affinity, cpumask_bits(&q->affinity_mask),
--
2.47.1