netdev - Re: [Intel-wired-lan] [PATCH 1/1 iwl-net] idpf: disable local BH when scheduling napi for marker packets

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

Message-ID: <0a7aa105-0b90-447d-5373-bf37b1a2cba4@intel.com>
Date: Mon, 12 Feb 2024 09:43:19 -0800
From: "Tantilov, Emil S" <emil.s.tantilov@...el.com>
To: Alexander Lobakin <aleksander.lobakin@...el.com>, Alan Brady
	<alan.brady@...el.com>
CC: <intel-wired-lan@...ts.osuosl.org>, Przemek Kitszel
	<przemyslaw.kitszel@...el.com>, <netdev@...r.kernel.org>, Jesse Brandeburg
	<jesse.brandeburg@...el.com>
Subject: Re: [Intel-wired-lan] [PATCH 1/1 iwl-net] idpf: disable local BH when
 scheduling napi for marker packets



On 2/12/2024 6:41 AM, Alexander Lobakin wrote:
> From: Alan Brady <alan.brady@...el.com>
> Date: Wed,  7 Feb 2024 16:42:43 -0800
> 
>> From: Emil Tantilov <emil.s.tantilov@...el.com>
>>
>> Fix softirq's not being handled during napi_schedule() call when
>> receiving marker packets for queue disable by disabling local bottom
>> half.
>>
>> The issue can be seen on ifdown:
>> NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #08!!!
>>
>> Using ftrace to catch the failing scenario:
>> ifconfig   [003] d.... 22739.830624: softirq_raise: vec=3 [action=NET_RX]
>> <idle>-0   [003] ..s.. 22739.831357: softirq_entry: vec=3 [action=NET_RX]
>>
>> No interrupt and CPU is idle.
>>
>> After the patch, with BH locks:
> 
> Minor: local_bh_{en,dis}able() are not "BH locks", it's BH
> enabling/disabling. It doesn't lock/unlock anything.

Good catch, we can change it to:
"After the patch when disabling local BH before calling napi_schedule:"

> 
>> ifconfig   [003] d.... 22993.928336: softirq_raise: vec=3 [action=NET_RX]
>> ifconfig   [003] ..s1. 22993.928337: softirq_entry: vec=3 [action=NET_RX]
>>
>> Fixes: c2d548cad150 ("idpf: add TX splitq napi poll support")
>> Reviewed-by: Jesse Brandeburg <jesse.brandeburg@...el.com>
>> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@...el.com>
>> Signed-off-by: Emil Tantilov <emil.s.tantilov@...el.com>
>> Signed-off-by: Alan Brady <alan.brady@...el.com>
> 
> Thanks,
> Olek

Thanks,
Emil