commit 06eb61844d841d0032a9950ce7f8e783ee49c0d0
author Peter Zijlstra <peterz@infradead.org> Fri Sep 22 18:30:40 2017 +0200
committer Ingo Molnar <mingo@kernel.org> Fri Sep 29 11:02:56 2017 +0200
tree 2c1db5ade5acc687e67f37d69e711bf0470df532
parent 5f6ad26ea353fdf3dad2328052cbee49e0b9c5b4

sched/debug: Add explicit TASK_IDLE printing

Markus reported that kthreads that idle using TASK_IDLE instead of
TASK_INTERRUPTIBLE are reported in as TASK_UNINTERRUPTIBLE and things
like htop mark those red.

This is undesirable, so add an explicit state for TASK_IDLE.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

fs/proc/array.c

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 01196d3a..a120a45 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -119,18 +119,23 @@ static inline void task_name(struct seq_file *m, struct task_struct *p)
  * simple bit tests.
  */
 static const char * const task_state_array[] = {
-	"R (running)",		/*   0 */
-	"S (sleeping)",		/*   1 */
-	"D (disk sleep)",	/*   2 */
-	"T (stopped)",		/*   4 */
-	"t (tracing stop)",	/*   8 */
-	"X (dead)",		/*  16 */
-	"Z (zombie)",		/*  32 */
+
+	/* states in TASK_REPORT: */
+	"R (running)",		/* 0x00 */
+	"S (sleeping)",		/* 0x01 */
+	"D (disk sleep)",	/* 0x02 */
+	"T (stopped)",		/* 0x04 */
+	"t (tracing stop)",	/* 0x08 */
+	"X (dead)",		/* 0x10 */
+	"Z (zombie)",		/* 0x20 */
+
+	/* states beyond TASK_REPORT: */
+	"I (idle)",		/* 0x40 */
 };
 
 static inline const char *get_task_state(struct task_struct *tsk)
 {
-	BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array) - 1);
+	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != ARRAY_SIZE(task_state_array));
 	return task_state_array[__get_task_state(tsk)];
 }