Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Thomas Gleixner:
 "The scheduler pull request comes with the following updates:

   - Prevent a divide by zero issue by validating the input value of
     sysctl_sched_time_avg

   - Make task state printing consistent all over the place and have
     explicit state characters for IDLE and PARKED so they wont be
     displayed as 'D' state which confuses tools"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/sysctl: Check user input value of sysctl_sched_time_avg
  sched/debug: Add explicit TASK_PARKED printing
  sched/debug: Ignore TASK_IDLE for SysRq-W
  sched/debug: Add explicit TASK_IDLE printing
  sched/tracing: Use common task-state helpers
  sched/tracing: Fix trace_sched_switch task-state printing
  sched/debug: Remove unused variable
  sched/debug: Convert TASK_state to hex
  sched/debug: Implement consistent task-state printing

fs/proc/array.c

@@ -119,30 +119,25 @@ 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 */
+	"P (parked)",		/* 0x40 */
+
+	/* states beyond TASK_REPORT: */
+	"I (idle)",		/* 0x80 */
 };
 
 static inline const char *get_task_state(struct task_struct *tsk)
 {
-	unsigned int state = (tsk->state | tsk->exit_state) & TASK_REPORT;
-
-	/*
-	 * Parked tasks do not run; they sit in __kthread_parkme().
-	 * Without this check, we would report them as running, which is
-	 * clearly wrong, so we report them as sleeping instead.
-	 */
-	if (tsk->state == TASK_PARKED)
-		state = TASK_INTERRUPTIBLE;
-
-	BUILD_BUG_ON(1 + ilog2(TASK_REPORT) != ARRAY_SIZE(task_state_array)-1);
-
-	return task_state_array[fls(state)];
+	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != ARRAY_SIZE(task_state_array));
+	return task_state_array[__get_task_state(tsk)];
 }
 
 static inline int get_task_umask(struct task_struct *tsk)

include/linux/sched.h

@@ -65,25 +65,23 @@ struct task_group;
  */
 
 /* Used in tsk->state: */
-#define TASK_RUNNING			0
-#define TASK_INTERRUPTIBLE		1
-#define TASK_UNINTERRUPTIBLE		2
-#define __TASK_STOPPED			4
-#define __TASK_TRACED			8
+#define TASK_RUNNING			0x0000
+#define TASK_INTERRUPTIBLE		0x0001
+#define TASK_UNINTERRUPTIBLE		0x0002
+#define __TASK_STOPPED			0x0004
+#define __TASK_TRACED			0x0008
 /* Used in tsk->exit_state: */
-#define EXIT_DEAD			16
-#define EXIT_ZOMBIE			32
+#define EXIT_DEAD			0x0010
+#define EXIT_ZOMBIE			0x0020
 #define EXIT_TRACE			(EXIT_ZOMBIE | EXIT_DEAD)
 /* Used in tsk->state again: */
-#define TASK_DEAD			64
-#define TASK_WAKEKILL			128
-#define TASK_WAKING			256
-#define TASK_PARKED			512
-#define TASK_NOLOAD			1024
-#define TASK_NEW			2048
-#define TASK_STATE_MAX			4096
-
-#define TASK_STATE_TO_CHAR_STR		"RSDTtXZxKWPNn"
+#define TASK_PARKED			0x0040
+#define TASK_DEAD			0x0080
+#define TASK_WAKEKILL			0x0100
+#define TASK_WAKING			0x0200
+#define TASK_NOLOAD			0x0400
+#define TASK_NEW			0x0800
+#define TASK_STATE_MAX			0x1000
 
 /* Convenience macros for the sake of set_current_state: */
 #define TASK_KILLABLE			(TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
@@ -99,7 +97,8 @@ struct task_group;
 /* get_task_state(): */
 #define TASK_REPORT			(TASK_RUNNING | TASK_INTERRUPTIBLE | \
 					 TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
-					 __TASK_TRACED | EXIT_ZOMBIE | EXIT_DEAD)
+					 __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \
+					 TASK_PARKED)
 
 #define task_is_traced(task)		((task->state & __TASK_TRACED) != 0)
 
@@ -1243,17 +1242,34 @@ static inline pid_t task_pgrp_nr(struct task_struct *tsk)
 	return task_pgrp_nr_ns(tsk, &init_pid_ns);
 }
 
-static inline char task_state_to_char(struct task_struct *task)
+#define TASK_REPORT_IDLE	(TASK_REPORT + 1)
+#define TASK_REPORT_MAX		(TASK_REPORT_IDLE << 1)
+
+static inline unsigned int __get_task_state(struct task_struct *tsk)
+{
+	unsigned int tsk_state = READ_ONCE(tsk->state);
+	unsigned int state = (tsk_state | tsk->exit_state) & TASK_REPORT;
+
+	BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX);
+
+	if (tsk_state == TASK_IDLE)
+		state = TASK_REPORT_IDLE;
+
+	return fls(state);
+}
+
+static inline char __task_state_to_char(unsigned int state)
 {
-	const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
-	unsigned long state = task->state;
+	static const char state_char[] = "RSDTtXZPI";
 
-	state = state ? __ffs(state) + 1 : 0;
+	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != sizeof(state_char) - 1);
 
-	/* Make sure the string lines up properly with the number of task states: */
-	BUILD_BUG_ON(sizeof(TASK_STATE_TO_CHAR_STR)-1 != ilog2(TASK_STATE_MAX)+1);
+	return state_char[state];
+}
 
-	return state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?';
+static inline char task_state_to_char(struct task_struct *tsk)
+{
+	return __task_state_to_char(__get_task_state(tsk));
 }
 
 /**

include/trace/events/sched.h

@@ -114,7 +114,10 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct *
 	 * Preemption ignores task state, therefore preempted tasks are always
 	 * RUNNING (we will not have dequeued if state != RUNNING).
 	 */
-	return preempt ? TASK_RUNNING | TASK_STATE_MAX : p->state;
+	if (preempt)
+		return TASK_STATE_MAX;
+
+	return __get_task_state(p);
 }
 #endif /* CREATE_TRACE_POINTS */
 
@@ -152,12 +155,14 @@ TRACE_EVENT(sched_switch,
 
 	TP_printk("prev_comm=%s prev_pid=%d prev_prio=%d prev_state=%s%s ==> next_comm=%s next_pid=%d next_prio=%d",
 		__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
-		__entry->prev_state & (TASK_STATE_MAX-1) ?
-		  __print_flags(__entry->prev_state & (TASK_STATE_MAX-1), "|",
-				{ 1, "S"} , { 2, "D" }, { 4, "T" }, { 8, "t" },
-				{ 16, "Z" }, { 32, "X" }, { 64, "x" },
-				{ 128, "K" }, { 256, "W" }, { 512, "P" },
-				{ 1024, "N" }) : "R",
+
+		(__entry->prev_state & (TASK_REPORT_MAX - 1)) ?
+		  __print_flags(__entry->prev_state & (TASK_REPORT_MAX - 1), "|",
+				{ 0x01, "S" }, { 0x02, "D" }, { 0x04, "T" },
+				{ 0x08, "t" }, { 0x10, "X" }, { 0x20, "Z" },
+				{ 0x40, "P" }, { 0x80, "I" }) :
+		  "R",
+
 		__entry->prev_state & TASK_STATE_MAX ? "+" : "",
 		__entry->next_comm, __entry->next_pid, __entry->next_prio)
 );

kernel/sched/core.c

@@ -5166,6 +5166,28 @@ void sched_show_task(struct task_struct *p)
 	put_task_stack(p);
 }
 
+static inline bool
+state_filter_match(unsigned long state_filter, struct task_struct *p)
+{
+	/* no filter, everything matches */
+	if (!state_filter)
+		return true;
+
+	/* filter, but doesn't match */
+	if (!(p->state & state_filter))
+		return false;
+
+	/*
+	 * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
+	 * TASK_KILLABLE).
+	 */
+	if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE)
+		return false;
+
+	return true;
+}
+
+
 void show_state_filter(unsigned long state_filter)
 {
 	struct task_struct *g, *p;
@@ -5188,7 +5210,7 @@ void show_state_filter(unsigned long state_filter)
 		 */
 		touch_nmi_watchdog();
 		touch_all_softlockup_watchdogs();
-		if (!state_filter || (p->state & state_filter))
+		if (state_filter_match(state_filter, p))
 			sched_show_task(p);
 	}
 

kernel/sched/debug.c

@@ -466,8 +466,6 @@ static char *task_group_path(struct task_group *tg)
 }
 #endif
 
-static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;
-
 static void
 print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
 {

kernel/sysctl.c

@@ -367,7 +367,8 @@ static struct ctl_table kern_table[] = {
 		.data		= &sysctl_sched_time_avg,
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
 	},
 #ifdef CONFIG_SCHEDSTATS
 	{

kernel/trace/trace_output.c

@@ -656,15 +656,6 @@ int trace_print_lat_context(struct trace_iterator *iter)
 	return !trace_seq_has_overflowed(s);
 }
 
-static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
-
-static int task_state_char(unsigned long state)
-{
-	int bit = state ? __ffs(state) + 1 : 0;
-
-	return bit < sizeof(state_to_char) - 1 ? state_to_char[bit] : '?';
-}
-
 /**
  * ftrace_find_event - find a registered event
  * @type: the type of event to look for
@@ -930,8 +921,8 @@ static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	T = task_state_char(field->next_state);
-	S = task_state_char(field->prev_state);
+	T = __task_state_to_char(field->next_state);
+	S = __task_state_to_char(field->prev_state);
 	trace_find_cmdline(field->next_pid, comm);
 	trace_seq_printf(&iter->seq,
 			 " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
@@ -966,8 +957,8 @@ static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		S = task_state_char(field->prev_state);
-	T = task_state_char(field->next_state);
+		S = __task_state_to_char(field->prev_state);
+	T = __task_state_to_char(field->next_state);
 	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
 			 field->prev_pid,
 			 field->prev_prio,
@@ -1002,8 +993,8 @@ static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
 	trace_assign_type(field, iter->ent);
 
 	if (!S)
-		S = task_state_char(field->prev_state);
-	T = task_state_char(field->next_state);
+		S = __task_state_to_char(field->prev_state);
+	T = __task_state_to_char(field->next_state);
 
 	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
 	SEQ_PUT_HEX_FIELD(s, field->prev_prio);

kernel/trace/trace_sched_wakeup.c

@@ -397,10 +397,10 @@ tracing_sched_switch_trace(struct trace_array *tr,
 	entry	= ring_buffer_event_data(event);
 	entry->prev_pid			= prev->pid;
 	entry->prev_prio		= prev->prio;
-	entry->prev_state		= prev->state;
+	entry->prev_state		= __get_task_state(prev);
 	entry->next_pid			= next->pid;
 	entry->next_prio		= next->prio;
-	entry->next_state		= next->state;
+	entry->next_state		= __get_task_state(next);
 	entry->next_cpu	= task_cpu(next);
 
 	if (!call_filter_check_discard(call, entry, buffer, event))
@@ -425,10 +425,10 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
 	entry	= ring_buffer_event_data(event);
 	entry->prev_pid			= curr->pid;
 	entry->prev_prio		= curr->prio;
-	entry->prev_state		= curr->state;
+	entry->prev_state		= __get_task_state(curr);
 	entry->next_pid			= wakee->pid;
 	entry->next_prio		= wakee->prio;
-	entry->next_state		= wakee->state;
+	entry->next_state		= __get_task_state(wakee);
 	entry->next_cpu			= task_cpu(wakee);
 
 	if (!call_filter_check_discard(call, entry, buffer, event))