rcu: Make rcupreempt_trace.c look at offline CPUs

Given that offline CPUs can now have non-zero counters, we need
to dump counters for offline CPUs as well as for online CPUs.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: josht@linux.vnet.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: hugh.dickins@tiscali.co.uk
Cc: benh@kernel.crashing.org
LKML-Reference: <12503552313921-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/rcupreempt_trace.c

@@ -236,12 +236,13 @@ static ssize_t rcuctrs_read(struct file *filp, char __user *buffer,
 
 	cnt += snprintf(&rcupreempt_trace_buf[cnt], RCUPREEMPT_TRACE_BUF_SIZE,
 				"CPU last cur F M\n");
-	for_each_online_cpu(cpu) {
+	for_each_possible_cpu(cpu) {
 		long *flipctr = rcupreempt_flipctr(cpu);
 		cnt += snprintf(&rcupreempt_trace_buf[cnt],
 				RCUPREEMPT_TRACE_BUF_SIZE - cnt,
-					"%3d %4ld %3ld %d %d\n",
+					"%3d%c %4ld %3ld %d %d\n",
 			       cpu,
+			       cpu_is_offline(cpu) ? '!' : ' ',
 			       flipctr[!f],
 			       flipctr[f],
 			       rcupreempt_flip_flag(cpu),