i386/142742: pmcstat segmentation fault with Intel Core CPU

[Luca Pizzamiglio]

>Number:         142742
>Category:       i386
>Synopsis:       pmcstat segmentation fault with Intel Core CPU
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Jan 12 11:10:00 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Luca Pizzamiglio
>Release:        7-STABLE
>Organization:
>Environment:
FreeBSD pcXX.xxxx.de 7.2-STABLE FreeBSD 7.2-STABLE #0 r2462M: Tue Dec 22 12:31:48 CET 2009     root at pcXX.xxxx.de:/usr/obj/usr/home/prog/svnsys/src_7stable/sys/BW7Dev  i386
>Description:
pmcstat utility crashes with a segmentation fault.
I've analyzed the problem that resides in the libpmc library.

For INTEL CORE architecture (PMC_CPU_INTEL_CORE), initialization of the pmc_class_table[] array of lib/libpmc/libpmc.c is not completed and this causes the segmentation fault during the use of the pmcstat utility.

The CPU I'm using now has the follow level 1 CPUID:
cpuid level 0x1: 0x000006ec 0x00010800 0x0000c109 0xafe9fbff
that means:
Family 0x600 and Model 0x0e


>How-To-Repeat:
Running pmcstat with an INTEL CORE CPU.
The problem appears both in sampling and counting mode.
>Fix:
I propose a patch to solve this problem: I've tested a bit and seems to work. 

This patch corrects the set up of the pmc_class_table[] array of lib/libpmc/libpmc.c when a PMC_CPU_INTEL_CORE CPU is recognized.



Patch attached with submission follows:

--- lib/libpmc/libpmc.c.orig	2010-01-11 16:43:47.000000000 +0100
+++ lib/libpmc/libpmc.c	2010-01-11 16:43:59.000000000 +0100
@@ -2507,6 +2507,7 @@
 		break;
 	case PMC_CPU_INTEL_CORE:
 		PMC_MDEP_INIT(core);
+		pmc_class_table[n] = &core_class_table_descr;
 		break;
 	case PMC_CPU_INTEL_CORE2:
 	case PMC_CPU_INTEL_CORE2EXTREME:


>Release-Note:
>Audit-Trail:
>Unformatted: