[Crash-utility] [PATCH 2/3] Add support for TASK_IDLE task state

[Kazuhito Hagio]

kernel commit 06eb61844d ("sched/debug: Add explicit TASK_IDLE
printing") exposed the TASK_IDLE task state to user space as
'I (idle)' state.
On the other hand, crash still shows 'UN' for TASK_IDLE state.

It is confusing for support folks, and 'foreach UN bt', which shows
useful information for troubles like system stall, includes unexpected
idle tasks.  So let's print TASK_IDLE as 'ID' state.

Signed-off-by: Kazuhito Hagio <k-hagio at ab.jp.nec.com>
---
 help.c |  4 ++--
 task.c | 22 +++++++++++++++++++++-
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/help.c b/help.c
index 54bf9b4..14cae8e 100644
--- a/help.c
+++ b/help.c
@@ -837,7 +837,7 @@ char *help_foreach[] = {
 "   kernel  perform the command(s) on all kernel threads.",
 "   active  perform the command(s) on the active thread on each CPU.",
 "    state  perform the command(s) on all tasks in the specified state, which",
-"           may be one of: RU, IN, UN, ST, ZO, TR, SW, DE, WA or PA.\n",
+"           may be one of: RU, IN, UN, ST, ZO, TR, SW, DE, WA, PA or ID.\n",
 "  If none of the task-identifying arguments above are entered, the command",
 "  will be performed on all tasks.\n",
 "  command  select one or more of the following commands to be run on the tasks",
@@ -1292,7 +1292,7 @@ char *help_ps[] = {
 "    3. the CPU number that the task ran on last.",
 "    4. the task_struct address or the kernel stack pointer of the process.",
 "       (see -s option below)",
-"    5. the task state (RU, IN, UN, ZO, ST, TR, DE, SW, WA, PA).",
+"    5. the task state (RU, IN, UN, ZO, ST, TR, DE, SW, WA, PA, ID).",
 "    6. the percentage of physical memory being used by this task.",
 "    7. the virtual address size of this task in kilobytes.",
 "    8. the resident set size of this task in kilobytes.",
diff --git a/task.c b/task.c
index 164e546..5412215 100644
--- a/task.c
+++ b/task.c
@@ -5539,7 +5539,11 @@ task_state_string(ulong task, char *buf, int verbose)
 	}
 
 	if (state & _UNINTERRUPTIBLE_) {
-		sprintf(buf, "UN");
+		if (valid_task_state(_NOLOAD_) &&
+		    (state & _NOLOAD_))
+			sprintf(buf, "ID");
+		else
+			sprintf(buf, "UN");
 		valid++; 
 		set++;
 	}
@@ -6282,6 +6286,7 @@ cmd_foreach(void)
 		    STREQ(args[optind], "DE") ||
 		    STREQ(args[optind], "PA") ||
 		    STREQ(args[optind], "WA") ||
+		    STREQ(args[optind], "ID") ||
 		    STREQ(args[optind], "SW")) {
 
 			if (fd->flags & FOREACH_STATE)
@@ -6307,6 +6312,8 @@ cmd_foreach(void)
 				fd->state = _PARKED_;
 			else if (STREQ(args[optind], "WA"))
 				fd->state = _WAKING_;
+			else if (STREQ(args[optind], "ID"))
+				fd->state = _UNINTERRUPTIBLE_|_NOLOAD_;
 
 			if (fd->state == TASK_STATE_UNINITIALIZED)
 				error(FATAL, 
@@ -6687,6 +6694,19 @@ foreach(struct foreach_data *fd)
 			if (fd->state == _RUNNING_) {
 				if (task_state(tc->task) != _RUNNING_)
 					continue;
+			} else if (fd->state & _UNINTERRUPTIBLE_) {
+				if (!(task_state(tc->task) & _UNINTERRUPTIBLE_))
+					continue;
+
+				if (valid_task_state(_NOLOAD_)) {
+					if (fd->state & _NOLOAD_) {
+						if (!(task_state(tc->task) & _NOLOAD_))
+							continue;
+					} else {
+						if ((task_state(tc->task) & _NOLOAD_))
+							continue;
+					}
+				}
 			} else if (!(task_state(tc->task) & fd->state))
 				continue;
 		}
-- 
1.8.3.1