linux-kernel - Re: [PATCH] EDAC, MCE, AMD: Fix code to prevent NULL dereference

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Message-ID: <20140217182729.GE4559@pd.tnic>
Date:	Mon, 17 Feb 2014 19:27:29 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Aravind Gopalakrishnan <Aravind.Gopalakrishnan@....com>
Cc:	dougthompson@...ssion.com, linux-edac@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] EDAC, MCE, AMD: Fix code to prevent NULL dereference

On Mon, Feb 17, 2014 at 11:49:51AM -0600, Aravind Gopalakrishnan wrote:
> If MCE decoding support does not exist for a particular family/model,
> and if one tries to inject errors using mce_amd_inj module, it leads
> to kernel OOPS. Especially if we inject errors to MC0, MC1, MC2 banks.

Well, we shouldn't even be loading the module on unsupported hw, i.e.,
something like that:

--
diff --git a/drivers/edac/mce_amd.c b/drivers/edac/mce_amd.c
index 30f7309446a6..3ef997bfb89d 100644
--- a/drivers/edac/mce_amd.c
+++ b/drivers/edac/mce_amd.c
@@ -816,10 +816,10 @@ static int __init mce_amd_init(void)
 	struct cpuinfo_x86 *c = &boot_cpu_data;
 
 	if (c->x86_vendor != X86_VENDOR_AMD)
-		return 0;
+		return -ENODEV;
 
 	if (c->x86 < 0xf || c->x86 > 0x16)
-		return 0;
+		return -ENODEV;
 
 	fam_ops = kzalloc(sizeof(struct amd_decoder_ops), GFP_KERNEL);
 	if (!fam_ops)

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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