EDAC/skx_common: Filter out the invalid address

Decoding an invalid address with certain firmware decoders could
cause a #PF (Page Fault) in the EFI runtime context, which could
subsequently hang the system. To make {i10nm,skx}_edac more robust
against such bogus firmware decoders, filter out invalid addresses
before allowing the firmware decoder to process them.

Suggested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20231207014512.78564-1-qiuxu.zhuo@intel.com

Author: qzhuo2

drivers/edac/skx_common.c

@@ -648,6 +648,10 @@ int skx_mce_check_error(struct notifier_block *nb, unsigned long val,
 	memset(&res, 0, sizeof(res));
 	res.mce  = mce;
 	res.addr = mce->addr & MCI_ADDR_PHYSADDR;
+	if (!pfn_to_online_page(res.addr >> PAGE_SHIFT)) {
+		pr_err("Invalid address 0x%llx in IA32_MC%d_ADDR\n", mce->addr, mce->bank);
+		return NOTIFY_DONE;
+	}
 
 	/* Try driver decoder first */
 	if (!(driver_decode && driver_decode(&res))) {