netdev - RE: [Intel-wired-lan] i40e: Fix preempt count leak in napi poll tracepoint

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <IA3PR11MB8986620478DE754429CA15FDE562A@IA3PR11MB8986.namprd11.prod.outlook.com>
Date: Tue, 10 Feb 2026 07:17:06 +0000
From: "Loktionov, Aleksandr" <aleksandr.loktionov@...el.com>
To: Thomas Gleixner <tglx@...nel.org>, "intel-wired-lan@...ts.osuosl.org"
	<intel-wired-lan@...ts.osuosl.org>
CC: "Nguyen, Anthony L" <anthony.l.nguyen@...el.com>, "Kitszel, Przemyslaw"
	<przemyslaw.kitszel@...el.com>, "netdev@...r.kernel.org"
	<netdev@...r.kernel.org>
Subject: RE: [Intel-wired-lan] i40e: Fix preempt count leak in napi poll
 tracepoint



> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@...osl.org> On Behalf
> Of Thomas Gleixner
> Sent: Saturday, February 7, 2026 11:50 AM
> To: intel-wired-lan@...ts.osuosl.org
> Cc: Nguyen, Anthony L <anthony.l.nguyen@...el.com>; Kitszel,
> Przemyslaw <przemyslaw.kitszel@...el.com>; netdev@...r.kernel.org
> Subject: [Intel-wired-lan] i40e: Fix preempt count leak in napi poll
> tracepoint
> 
> 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@...nel.org>
> Cc: Tony Nguyen <anthony.l.nguyen@...el.com>
> Cc: Przemek Kitszel <przemyslaw.kitszel@...el.com>
> Cc: intel-wired-lan@...ts.osuosl.org
> Cc: netdev@...r.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),

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@...el.com>