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From: Tony Luck <tony.luck@intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "x86@kernel.org" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] RAS: Fix the trace_show() function to output trace_count
Date: Tue, 18 Oct 2022 07:36:53 -0700	[thread overview]
Message-ID: <Y066BV4jiRMxgjYV@agluck-desk3.sc.intel.com> (raw)
In-Reply-To: <Y02vmRn1Uz6/NMFF@zn.tnic>

On Mon, Oct 17, 2022 at 09:40:09PM +0200, Borislav Petkov wrote:
> Question is, what is your goal with this?

I ran into it while fixing:

  https://lore.kernel.org/all/20221006163258.318916-1-tony.luck@intel.com/

when I just used "cat daemon_active" to check status and was confused
by the lack of any output. Looked at the code and saw the silly

	return atomic_read(&trace_count);

which does nothing useful.

Maybe if there isn't a reasonable thing to output, that could be
changed to:

static int trace_show(struct seq_file *m, void *v)
{
	/*
	 * User should use "lsof daemon_active" if they want to 
	 * know if there is a process consuming trace error records
	 */
	return 0;
}

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" :-(

-Tony

  reply	other threads:[~2022-10-18 14:37 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-05 16:16 [PATCH] RAS: Fix the trace_show() function to output trace_count Tony Luck
2022-10-05 18:17 ` Borislav Petkov
2022-10-05 19:46   ` [PATCH v2] " Tony Luck
2022-10-17 10:36     ` Borislav Petkov
2022-10-17 16:09       ` Luck, Tony
2022-10-17 19:40         ` Borislav Petkov
2022-10-18 14:36           ` Tony Luck [this message]
2022-10-18 16:05             ` Borislav Petkov
2022-10-18 16:59             ` [PATCH v3] RAS: Fix return value from show_trace() Tony Luck
2022-10-31 18:15               ` [tip: ras/core] " tip-bot2 for Tony Luck

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