Subject: + wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space.patch added to -mm tree
To: oleg@xxxxxxxxxx,jan.kratochvil@xxxxxxxxxx,lpoetter@xxxxxxxxxx,mschmidt@xxxxxxxxxx,roland@xxxxxxxxxxxxx,tj@xxxxxxxxxx,viro@xxxxxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Fri, 21 Feb 2014 13:39:21 -0800
The patch titled
Subject: wait: swap EXIT_ZOMBIE and EXIT_DEAD to hide EXIT_TRACE from user-space
has been added to the -mm tree. Its filename is
wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Cc: Jan Kratochvil <jan.kratochvil@xxxxxxxxxx>
Cc: Michal Schmidt <mschmidt@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Lennart Poettering <lpoetter@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/array.c | 4 ++--
include/linux/sched.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff -puN fs/proc/array.c~wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space fs/proc/array.c
--- a/fs/proc/array.c~wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space
+++ a/fs/proc/array.c
@@ -138,8 +138,8 @@ static const char * const task_state_arr
"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 -puN include/linux/sched.h~wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space include/linux/sched.h
--- a/include/linux/sched.h~wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space
+++ a/include/linux/sched.h
@@ -204,8 +204,8 @@ print_cfs_rq(struct seq_file *m, int cpu
#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
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
kthread-ensure-locality-of-task_struct-allocations.patch
wait-fix-reparent_leader-vs-exit_dead-exit_zombie-race.patch
wait-introduce-exit_trace-to-avoid-the-racy-exit_dead-exit_zombie-transition.patch
wait-use-exit_trace-only-if-thread_group_leaderzombie.patch
wait-completely-ignore-the-exit_dead-tasks.patch
wait-swap-exit_zombie-and-exit_dead-to-hide-exit_trace-from-user-space.patch
linux-next.patch
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