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

From: Borislav Petkov
Date: Tue Feb 18 2014 - 03:47:13 EST


Ok, let's try a simpler thing. Only build-tested here:

---
diff --git a/drivers/edac/mce_amd.c b/drivers/edac/mce_amd.c
index 30f7309446a6..30592838f1da 100644
--- a/drivers/edac/mce_amd.c
+++ b/drivers/edac/mce_amd.c
@@ -738,6 +738,9 @@ int amd_decode_mce(struct notifier_block *nb, unsigned long val, void *data)
struct cpuinfo_x86 *c = &cpu_data(m->extcpu);
int ecc;

+ if (!fam_ops)
+ return NOTIFY_DONE;
+
if (amd_filter_mce(m))
return NOTIFY_STOP;

@@ -816,10 +819,10 @@ 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)
@@ -874,6 +877,7 @@ static int __init mce_amd_init(void)
default:
printk(KERN_WARNING "Huh? What family is it: 0x%x?!\n", c->x86);
kfree(fam_ops);
+ fam_ops = NULL;
return -EINVAL;
}


--
Regards/Gruss,
Boris.

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