From ad86622b478eaafdc25b74237df82b10fce6326d Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Mon, 7 Apr 2014 15:38:46 -0700
Subject: [PATCH] wait: swap EXIT_ZOMBIE and EXIT_DEAD to hide EXIT_TRACE from
user-space
get_task_state() uses the most significant bit to report the state to
user-space, this means that EXIT_ZOMBIE->EXIT_TRACE->EXIT_DEAD transition
can be noticed via /proc as Z -> X -> Z change. Note that this was
possible even before EXIT_TRACE was introduced.
This is not really bad but imho it make sense to hide EXIT_TRACE from
user-space completely. So the patch simply swaps EXIT_ZOMBIE and
EXIT_DEAD, this way EXIT_TRACE will be seen as EXIT_ZOMBIE by user-space.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Michal Schmidt <mschmidt@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Lennart Poettering <lpoetter@redhat.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/proc/array.c | 4 ++--
include/linux/sched.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 656e401794de..64db2bceac59 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -138,8 +138,8 @@ static const char * const task_state_array[] = {
"D (disk sleep)", /* 2 */
"T (stopped)", /* 4 */
"t (tracing stop)", /* 8 */
- "Z (zombie)", /* 16 */
- "X (dead)", /* 32 */
+ "X (dead)", /* 16 */
+ "Z (zombie)", /* 32 */
};
static inline const char *get_task_state(struct task_struct *tsk)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7781de5e5e7b..075b3056c0c0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -210,8 +210,8 @@ print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);
#define __TASK_STOPPED 4
#define __TASK_TRACED 8
/* in tsk->exit_state */
-#define EXIT_ZOMBIE 16
-#define EXIT_DEAD 32
+#define EXIT_DEAD 16
+#define EXIT_ZOMBIE 32
#define EXIT_TRACE (EXIT_ZOMBIE | EXIT_DEAD)
/* in tsk->state again */
#define TASK_DEAD 64
--
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