From: Thomas Gleixner <tglx@kernel.org>
To: intel-wired-lan@lists.osuosl.org
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>,
Przemek Kitszel <przemyslaw.kitszel@intel.com>,
netdev@vger.kernel.org
Subject: i40e: Fix preempt count leak in napi poll tracepoint
Date: Sat, 07 Feb 2026 11:50:23 +0100 [thread overview]
Message-ID: <87v7g8zv2o.ffs@tglx> (raw)
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
---
drivers/net/ethernet/intel/i40e/i40e_trace.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- 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),
next reply other threads:[~2026-02-07 10:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-07 10:50 Thomas Gleixner [this message]
2026-02-09 22:07 ` i40e: Fix preempt count leak in napi poll tracepoint Joe Damato
2026-02-09 22:56 ` Thomas Gleixner
2026-02-10 0:25 ` Thomas Gleixner
2026-02-10 2:58 ` Joe Damato
2026-02-10 7:17 ` [Intel-wired-lan] " Loktionov, Aleksandr
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87v7g8zv2o.ffs@tglx \
--to=tglx@kernel.org \
--cc=anthony.l.nguyen@intel.com \
--cc=intel-wired-lan@lists.osuosl.org \
--cc=netdev@vger.kernel.org \
--cc=przemyslaw.kitszel@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox