Re: Linux 2.4.19-pre3

[Mikael Pettersson]

Marcelo wrote in the 2.4.19-pre3 announcement:
>pre3:
>- Fix off-by-one error in bluesmoke			(Dave Jones)

NO NO NO! This is the same broken patch that somehow got into
2.2.21pre4 as well. The patch changes the code to write to the
IA32_MC0_CTL MSR, which is a big no-no. Intel's IA32 Vol3 manual
(#245472-03) sections 13.3.2.1 and 13.5 make that point quite clear.

I have several P6 boxes that hang hard in MCE init trying to boot
vanilla 2.2.21pre4 and 2.4.19-pre3. The issue is real.

Please apply the backup patch below.

/Mikael

--- linux-2.4.19-pre3/arch/i386/kernel/bluesmoke.c.~1~	Tue Mar 12 00:25:53 2002
+++ linux-2.4.19-pre3/arch/i386/kernel/bluesmoke.c	Tue Mar 12 01:11:58 2002
@@ -169,7 +169,7 @@
 	if(l&(1<<8))
 		wrmsr(MSR_IA32_MCG_CTL, 0xffffffff, 0xffffffff);
 	banks = l&0xff;
-	for(i=0;i<banks;i++)
+	for(i=1;i<banks;i++)
 	{
 		wrmsr(MSR_IA32_MC0_CTL+4*i, 0xffffffff, 0xffffffff);
 	}