linux-kernel - Re: [PATCH] genirq/debugfs: add new config option for trigger interrupt from userspace

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Date:   Fri, 28 Feb 2020 19:54:04 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     Joe Jin <joe.jin@...cle.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] genirq/debugfs: add new config option for trigger
 interrupt from userspace

On 2020-02-28 19:13, Joe Jin wrote:
> Hi Marc,
> 
> Thanks for your reply.
> 
> On 2/28/20 8:37 AM, Marc Zyngier wrote:
>> On 2020-02-28 05:42, Joe Jin wrote:
>>> commit 536e2e34bd00 ("genirq/debugfs: Triggering of interrupts from
>>> userspace") is allowed developer inject interrupts via irq debugfs, 
>>> which
>>> is very useful during development phase, but on a production system, 
>>> this
>>> is very dangerous, add new config option, developers can enable it as
>>> needed instead of enabling it by default when irq debugfs is enabled.
>> 
>> I don't really mind the patch (although it could be more elegant), but 
>> in
>> general I object to most debugfs options being set on a production 
>> kernel.
>> There is way too much information in most debugfs backends to be 
>> comfortable
>> with it, and you can find things like page table dumps, for example...
> 
> We should not enable any debug option on production system, actual 
> customer
> want to resize their BM or VM, cpu offline may lead system not works 
> properly,
> and if we knew more details of IRQ info it will be very help to 
> identify
> if it caused by IRQ/vectors, this is the motivation of we want to 
> enable it
> on production kernel.

If something doesn't work properly, then you are still debugging, 
AFAICT.

         M.
-- 
Jazz is not dead. It just smells funny...