linux-kernel - Re: [PATCH v2] RAS: Fix the trace_show() function to output trace

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Message-ID: <Y07OsE+B9HwZPD0z@zn.tnic>
Date:   Tue, 18 Oct 2022 18:05:04 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Tony Luck <tony.luck@...el.com>
Cc:     "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] RAS: Fix the trace_show() function to output
 trace_count

On Tue, Oct 18, 2022 at 07:36:53AM -0700, Tony Luck wrote:
> Sadly, we need to have a trace_show() function. If trace_open() just
> does:
> 
> 	return single_open(file, NULL, NULL);
> 
> then we get a deref NULL OOPs if somebody does "cat daemon_active" :-(

I guess but as you see yourself, cat-ting that file is done only by
us when debugging stuff. So we shouldn't waste too much energy on
"designing" an interface. As nothing'll use it.

But sure, trace_show(), why not.

I mean, if people go and open that file and confuse the system, they'll
only have themselves to blame. Besides, it is debugfs and root-only and
so on - if you wanna do damage, you already have root.

So yeah, let's keep this effort minimal and only address valid use cases.

IMO.

Thx.

-- 
Regards/Gruss,
    Boris.

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