linux-kernel - Re: [PATCH 2/3] x86, RAS: Add a decoded msg buffer

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Message-ID: <20120229101146.GB21224@aftab>
Date:	Wed, 29 Feb 2012 11:11:46 +0100
From:	Borislav Petkov <bp@...64.org>
To:	"Luck, Tony" <tony.luck@...el.com>
Cc:	Ingo Molnar <mingo@...e.hu>,
	EDAC devel <linux-edac@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Borislav Petkov <borislav.petkov@....com>
Subject: Re: [PATCH 2/3] x86, RAS: Add a decoded msg buffer

On Tue, Feb 28, 2012 at 10:43:52PM +0000, Luck, Tony wrote:
> +	if (left <= 50) {
> +		/* enlarge arbitrarily by 50 chars */
> +		err_str_sz += 50;
> +		left += 50;
> +
> +		err_str = krealloc(err_str, err_str_sz, GFP_KERNEL);
> +		if (!err_str) {
> +			pr_err("Error enlarging decode buffer.\n");
> +			return;
> +		}
> +	}
> 
> This looks worrying to me.  Some bad stuff has happened, we are perhaps
> in machine check context, and you want to start allocating memory!

Yes, absolutely. See my other mail to Seto-san.

> Is there some upper bound for how long this string can get? Why not
> just allocate a generous amount at boot time?

Yep, this sounds like the easiest thing to do, let me play with MCE
injection a bit.

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Boris.

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