kern/146590: MCA panics 7.3

[Walter C. Pelissero]

>Number:         146590
>Category:       kern
>Synopsis:       MCA panics 7.3
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri May 14 16:50:05 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Walter C. Pelissero
>Release:        FreeBSD 7.3-STABLE i386
>Organization:
>Environment:
System: FreeBSD zaphod.home.lan 7.3-STABLE FreeBSD 7.3-STABLE #0: Fri May 14 13:43:05 CEST 2010 root at zaphod.home.lan:/usr/src/sys/i386/compile/TIGER-MP i386


	
>Description:
	FreeBSD 7.3-STABLE on a Tyan Tiger MP (S2460) panics almost
	upon loading the kernel.

	The screen reads something like:
	real memory  = [...]
	avail memory = [...]
	ACPI APIC Table: <PTLTD APIC>
	FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
	 cpu0 (BSP): APIC ID: 1
	 cpu1 (AP): APIC ID: 0
	MCA: Bank 0, Status 0xf662a00000000833
	MCA: Global Cap 0x0000000000000104, Status 0x0000000000000004
	MCA: Vendor "AuthenticAMD", ID 0x681, APIC ID 1
	MCA: CPU 0 UNCOR PCC OVER BUSLG Source DRD Memory
	MCA: Address 0xe4000

	Fatal trap 28: machine check trap while in kernel mode
	cpuid = 0; apic id = 01
	instruction pointer = 0x20:0xc06ebc03
	stack pointer       = 0x28:0xc0c20d1c
	frame pointer       = 0x28:0xc0c20d44
	doce segment        = base 0x0, limit 0xfffff, type 0x1b
	                    = DPL 0, pres 1, def32 1, gran 1
	processor eflags    = interrupt enabled, IOPL = 0
	current process     = 0
	[thread pid 0 tid 0 ]
	Stopped at    bios_sigsearch+0x93:  leal  0(%ebx,%eax,1),xedx
	db>

	This machine had no problem at least until short before
	7.3-RELEASE, so I'd rule out an actual hardware error.
	
>How-To-Repeat:
	Boot a generic kernel on a Tyan Tiger MP (S2460).
>Fix:

	Setting hw.mca.enabled=0 works around the problem.
>Release-Note:
>Audit-Trail:
>Unformatted: