svn commit: r230636 - head/sys/dev/hwpmc

[Ed Maste]

Author: emaste
Date: Sat Jan 28 01:38:48 2012
New Revision: 230636
URL: http://svn.freebsd.org/changeset/base/230636

Log:
  pmc_*_initialize may return NULL if the CPU is not supported, so check
  that md is not null before dereferencing it.
  
  PR:		kern/156540

Modified:
  head/sys/dev/hwpmc/hwpmc_x86.c

Modified: head/sys/dev/hwpmc/hwpmc_x86.c
==============================================================================
--- head/sys/dev/hwpmc/hwpmc_x86.c	Sat Jan 28 00:17:17 2012	(r230635)
+++ head/sys/dev/hwpmc/hwpmc_x86.c	Sat Jan 28 01:38:48 2012	(r230636)
@@ -250,7 +250,7 @@ pmc_md_initialize()
 		return (NULL);
 
 	/* disallow sampling if we do not have an LAPIC */
-	if (!lapic_enable_pmc())
+	if (md != NULL && !lapic_enable_pmc())
 		for (i = 1; i < md->pmd_nclass; i++)
 			md->pmd_classdep[i].pcd_caps &= ~PMC_CAP_INTERRUPT;