Index: sys/compat/linprocfs/linprocfs.c
===================================================================
--- sys/compat/linprocfs/linprocfs.c
+++ sys/compat/linprocfs/linprocfs.c
@@ -469,9 +469,51 @@
 	return (0);
 }
 
+/*
+ * Compare a given Linux kernel version string against
+ * the system / jail version and returns an integer greater than, equal to,
+ * or less than zero, according as the version is greater than, equal to, or
+ * less than the system / jail version.
+ */
+static int
+linprocfs_osrelease_cmp(struct thread *td, const char *rel)
+{
+	char osrelease[LINUX_MAX_UTSNAME];
+	int os_ver[3] = {0, 0, 0};	/* OS kernel version, major, minor */
+	int cmp_ver[3] = {0, 0, 0};	/* Compare kernel version, major, minor */
+	int i;
+
+	linux_get_osrelease(td, osrelease);
+
+	sscanf(osrelease, "%d.%d.%d", &os_ver[0], &os_ver[1], &os_ver[2]);
+	sscanf(rel, "%d.%d.%d", &cmp_ver[0], &cmp_ver[1], &cmp_ver[2]);
+
+	for (i = 0; i < 3; i++) {
+		if (os_ver[i] > cmp_ver[i]) {
+			return (1);
+		} else if (os_ver[i] < cmp_ver[i]) {
+			return (-1);
+		}
+	}
+
+	return (0);
+}
 
 /*
  * Filler function for proc/stat
+ *
+ * Output depends on kernel version:
+ *
+ * v2.5.40 <=
+ *   user, nice, system, idle
+ * v2.5.41
+ *   user, nice, system, idle, iowait
+ * v2.6.11
+ *   user, nice, system, idle, iowait, irq, softirq, steal
+ * v2.6.24
+ *   user, nice, system, idle, iowait, irq, softirq, steal, guest
+ * v2.6.33 >=
+ *   user, nice, system, idle, iowait, irq, softirq, steal, guest, guest_nice
  */
 static int
 linprocfs_dostat(PFS_FILL_ARGS)
@@ -481,22 +523,44 @@
 	long *cp;
 	struct timeval boottime;
 	int i;
+	const char *cpu_fmtstr, *cpun_fmtstr;
+
+	if (linprocfs_osrelease_cmp(td, "2.6.33") >= 0) {
+		cpu_fmtstr = "cpu %lu %lu %lu %lu 0 %lu 0 0 0 0\n";
+		cpun_fmtstr = "cpu%d %lu %lu %lu %lu 0 %lu 0 0 0 0\n";
+	} else if (linprocfs_osrelease_cmp(td, "2.6.24") >= 0) {
+		cpu_fmtstr = "cpu %lu %lu %lu %lu 0 %lu 0 0 0\n";
+		cpun_fmtstr = "cpu%d %lu %lu %lu %lu 0 %lu 0 0 0\n";
+	} else if (linprocfs_osrelease_cmp(td, "2.6.11") >= 0) {
+		cpu_fmtstr = "cpu %lu %lu %lu %lu 0 %lu 0 0\n";
+		cpun_fmtstr = "cpu%d %lu %lu %lu %lu 0 %lu 0 0\n";
+	} else if (linprocfs_osrelease_cmp(td, "2.5.41") >= 0) {
+		/* Note: these format strings purposely drop a parameter */
+		cpu_fmtstr = "cpu %lu %lu %lu %lu 0\n";
+		cpun_fmtstr = "cpu%d %lu %lu %lu %lu 0\n";
+	} else {
+		/* Note: these format strings purposely drop parameters */
+		cpu_fmtstr = "cpu %lu %lu %lu %lu\n";
+		cpun_fmtstr = "cpu%d %lu %lu %lu %lu\n";
+	}
 
 	read_cpu_time(cp_time);
 	getboottime(&boottime);
-	sbuf_printf(sb, "cpu %ld %ld %ld %ld\n",
+	sbuf_printf(sb, cpu_fmtstr,
 	    T2J(cp_time[CP_USER]),
 	    T2J(cp_time[CP_NICE]),
-	    T2J(cp_time[CP_SYS] /*+ cp_time[CP_INTR]*/),
-	    T2J(cp_time[CP_IDLE]));
+	    T2J(cp_time[CP_SYS]),
+	    T2J(cp_time[CP_IDLE]),
+	    T2J(cp_time[CP_INTR]));
 	CPU_FOREACH(i) {
 		pcpu = pcpu_find(i);
 		cp = pcpu->pc_cp_time;
-		sbuf_printf(sb, "cpu%d %ld %ld %ld %ld\n", i,
-		    T2J(cp[CP_USER]),
-		    T2J(cp[CP_NICE]),
-		    T2J(cp[CP_SYS] /*+ cp[CP_INTR]*/),
-		    T2J(cp[CP_IDLE]));
+		sbuf_printf(sb, cpun_fmtstr, i,
+		    T2J(cp_time[CP_USER]),
+		    T2J(cp_time[CP_NICE]),
+		    T2J(cp_time[CP_SYS]),
+		    T2J(cp_time[CP_IDLE]),
+		    T2J(cp_time[CP_INTR]));
 	}
 	sbuf_printf(sb,
 	    "disk 0 0 0 0\n"