From: charles_xu@189.cn
To: tglx@kernel.org, anthony.l.nguyen@intel.com,
przemyslaw.kitszel@intel.com, intel-wired-lan@lists.osuosl.org,
netdev@vger.kernel.org, joe@dama.to,
aleksandr.loktionov@intel.com, stable@vger.kernel.org
Subject: [PATCH 6.6.y] i40e: Fix preempt count leak in napi poll tracepoint
Date: Tue, 21 Apr 2026 15:18:38 +0800 [thread overview]
Message-ID: <20260421071838.3878-1-charles_xu@189.cn> (raw)
From: Thomas Gleixner <tglx@kernel.org>
[ Upstream commit 4b3d54a85bd37ebf2d9836f0d0de775c0ff21af9 ]
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 <joe@dama.to>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Charles Xu <charles_xu@189.cn>
---
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 33b4e30f5e00..9b735a9e2114 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, q->name);
__assign_str(dev_name, napi->dev ? napi->dev->name : NO_DEV);
__assign_bitmask(irq_affinity, cpumask_bits(&q->affinity_mask),
--
2.35.3
next reply other threads:[~2026-04-21 7:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-21 7:18 charles_xu [this message]
2026-04-23 17:38 ` [PATCH 6.6.y] i40e: Fix preempt count leak in napi poll tracepoint Jacob Keller
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