2 files changed, 12 insertions, 6 deletions

diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX
index f54273e2ac97..ceb1ff735469 100644
--- a/Documentation/00-INDEX
+++ b/Documentation/00-INDEX
@@ -210,6 +210,8 @@ local_ops.txt
         - semantics and behavior of local atomic operations.
 lockdep-design.txt
         - documentation on the runtime locking correctness validator.
+lockup-watchdogs.txt
+        - info on soft and hard lockup detectors (aka nmi_watchdog).
 logo.gif
         - full colour GIF image of Linux logo (penguin - Tux).
 logo.txt
@@ -240,8 +242,6 @@ netlabel/
         - directory with information on the NetLabel subsystem.
 networking/
         - directory with info on various aspects of networking with Linux.
-nmi_watchdog.txt
-        - info on NMI watchdog for SMP systems.
 nommu-mmap.txt
         - documentation about no-mmu memory mapping support.
 numastat.txt
diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 64c3b3172367..e296572c73ed 100644
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -45,10 +45,13 @@ static cputime64_t get_iowait_time(int cpu)
 
 static u64 get_idle_time(int cpu)
 {
-        u64 idle, idle_time = get_cpu_idle_time_us(cpu, NULL);
+        u64 idle, idle_time = -1ULL;
+
+        if (cpu_online(cpu))
+                idle_time = get_cpu_idle_time_us(cpu, NULL);
 
         if (idle_time == -1ULL)
-                /* !NO_HZ so we can rely on cpustat.idle */
+                /* !NO_HZ or cpu offline so we can rely on cpustat.idle */
                 idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];
         else
                 idle = usecs_to_cputime64(idle_time);
@@ -58,10 +61,13 @@ static u64 get_idle_time(int cpu)
 
 static u64 get_iowait_time(int cpu)
 {
-        u64 iowait, iowait_time = get_cpu_iowait_time_us(cpu, NULL);
+        u64 iowait, iowait_time = -1ULL;
+
+        if (cpu_online(cpu))
+                iowait_time = get_cpu_iowait_time_us(cpu, NULL);
 
         if (iowait_time == -1ULL)
-                /* !NO_HZ so we can rely on cpustat.iowait */
+                /* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
                 iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];
         else
                 iowait = usecs_to_cputime64(iowait_time);