The patch titled
ptrace: introduce task_detached() helper
has been added to the -mm tree. Its filename is
ptrace-introduce-task_detached-helper.patch
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See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: ptrace: introduce task_detached() helper
From: Oleg Nesterov <oleg@xxxxxxxxxx>
exit.c has numerous "->exit_signal == -1" comparisons, this check is subtle
and deserves a helper. Imho makes the code more parseable for humans. At
least it's surely more greppable.
Also, a couple of whitespace cleanups. No functional changes.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/exit.c | 45 +++++++++++++++++++++++++--------------------
1 file changed, 25 insertions(+), 20 deletions(-)
diff -puN kernel/exit.c~ptrace-introduce-task_detached-helper kernel/exit.c
--- a/kernel/exit.c~ptrace-introduce-task_detached-helper
+++ a/kernel/exit.c
@@ -52,6 +52,11 @@
static void exit_mm(struct task_struct * tsk);
+static inline int task_detached(struct task_struct *p)
+{
+ return p->exit_signal == -1;
+}
+
static void __unhash_process(struct task_struct *p)
{
nr_threads--;
@@ -160,7 +165,7 @@ repeat:
zap_leader = 0;
leader = p->group_leader;
if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) {
- BUG_ON(leader->exit_signal == -1);
+ BUG_ON(task_detached(leader));
do_notify_parent(leader, leader->exit_signal);
/*
* If we were the last child thread and the leader has
@@ -170,7 +175,7 @@ repeat:
* do_notify_parent() will have marked it self-reaping in
* that case.
*/
- zap_leader = (leader->exit_signal == -1);
+ zap_leader = task_detached(leader);
}
write_unlock_irq(&tasklist_lock);
@@ -655,14 +660,14 @@ reparent_thread(struct task_struct *p, s
return;
/* We don't want people slaying init. */
- if (p->exit_signal != -1)
+ if (!task_detached(p))
p->exit_signal = SIGCHLD;
/* If we'd notified the old parent about this child's death,
* also notify the new parent.
*/
if (!traced && p->exit_state == EXIT_ZOMBIE &&
- p->exit_signal != -1 && thread_group_empty(p))
+ !task_detached(p) && thread_group_empty(p))
do_notify_parent(p, p->exit_signal);
kill_orphaned_pgrp(p, father);
@@ -715,18 +720,18 @@ static void forget_original_parent(struc
} else {
/* reparent ptraced task to its real parent */
__ptrace_unlink (p);
- if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
+ if (p->exit_state == EXIT_ZOMBIE && !task_detached(p) &&
thread_group_empty(p))
do_notify_parent(p, p->exit_signal);
}
/*
- * if the ptraced child is a zombie with exit_signal == -1
- * we must collect it before we exit, or it will remain
- * zombie forever since we prevented it from self-reap itself
- * while it was being traced by us, to be able to see it in wait4.
+ * if the ptraced child is a detached zombie we must collect
+ * it before we exit, or it will remain zombie forever since
+ * we prevented it from self-reap itself while it was being
+ * traced by us, to be able to see it in wait4.
*/
- if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && p->exit_signal == -1))
+ if (unlikely(ptrace && p->exit_state == EXIT_ZOMBIE && task_detached(p)))
list_add(&p->ptrace_list, &ptrace_dead);
}
@@ -783,26 +788,26 @@ static void exit_notify(struct task_stru
* we have changed execution domain as these two values started
* the same after a fork.
*/
- if (tsk->exit_signal != SIGCHLD && tsk->exit_signal != -1 &&
+ if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) &&
(tsk->parent_exec_id != tsk->real_parent->self_exec_id ||
- tsk->self_exec_id != tsk->parent_exec_id)
- && !capable(CAP_KILL))
+ tsk->self_exec_id != tsk->parent_exec_id) &&
+ !capable(CAP_KILL))
tsk->exit_signal = SIGCHLD;
-
/* If something other than our normal parent is ptracing us, then
* send it a SIGCHLD instead of honoring exit_signal. exit_signal
* only has special meaning to our real parent.
*/
- if (tsk->exit_signal != -1 && thread_group_empty(tsk)) {
- int signal = tsk->parent == tsk->real_parent ? tsk->exit_signal : SIGCHLD;
+ if (!task_detached(tsk) && thread_group_empty(tsk)) {
+ int signal = (tsk->parent == tsk->real_parent)
+ ? tsk->exit_signal : SIGCHLD;
do_notify_parent(tsk, signal);
} else if (tsk->ptrace) {
do_notify_parent(tsk, SIGCHLD);
}
state = EXIT_ZOMBIE;
- if (tsk->exit_signal == -1 && likely(!tsk->ptrace))
+ if (task_detached(tsk) && likely(!tsk->ptrace))
state = EXIT_DEAD;
tsk->exit_state = state;
@@ -1107,7 +1112,7 @@ static int eligible_child(enum pid_type
* Do not consider detached threads that are
* not ptraced:
*/
- if (p->exit_signal == -1 && !p->ptrace)
+ if (task_detached(p) && !p->ptrace)
return 0;
/* Wait for all children (clone and not) if __WALL is set;
@@ -1299,9 +1304,9 @@ static int wait_task_zombie(struct task_
* If it's still not detached after that, don't release
* it now.
*/
- if (p->exit_signal != -1) {
+ if (!task_detached(p)) {
do_notify_parent(p, p->exit_signal);
- if (p->exit_signal != -1) {
+ if (!task_detached(p)) {
p->exit_state = EXIT_ZOMBIE;
p = NULL;
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
git-hrt.patch
kthread-call-wake_up_process-without-the-lock-being-held.patch
documentation-atomic_add_unless-doesnt-imply-mb-on-failure-fix.patch
mmap_region-cleanup-the-final-vma_merge-related-code.patch
remove-unused-variable-from-send_signal.patch
turn-legacy_queue-macro-into-static-inline-function.patch
consolidate-checking-for-ignored-legacy-signals.patch
consolidate-checking-for-ignored-legacy-signals-simplify.patch
signals-do_signal_stop-use-signal_group_exit.patch
signals-do_group_exit-use-signal_group_exit-more-consistently.patch
lock_task_sighand-add-rcu-lock-unlock.patch
k_getrusage-dont-take-rcu_read_lock.patch
do_task_stat-dont-take-rcu_read_lock.patch
signals-consolidate-checks-for-whether-or-not-to-ignore-a-signal.patch
signals-clean-dequeue_signal-from-excess-checks-and-assignments.patch
signals-consolidate-send_sigqueue-and-send_group_sigqueue.patch
signals-cleanup-security_task_kill-usage-implementation.patch
introduce-kill_orphaned_pgrp-helper.patch
will_become_orphaned_pgrp-partially-fix-insufficient-exit_state-check.patch
exit_notify-fix-kill_orphaned_pgrp-usage-with-mt-exit.patch
ptrace-introduce-task_detached-helper.patch
ptrace-introduce-ptrace_reparented-helper.patch
reparent_thread-use-same_thread_group.patch
document-de_thread-with-exit_notify-connection.patch
workqueues-shrink-cpu_populated_map-when-cpu-dies.patch
workqueues-shrink-cpu_populated_map-when-cpu-dies-fix.patch
cleanup_workqueue_thread-remove-the-unneeded-cpu-parameter.patch
simplify-cpu_hotplug_begin-put_online_cpus.patch
redo-locking-of-tty-pgrp.patch
resume-tty-on-susp-and-fix-crnl-order-in-n_tty-line-discipline.patch
procfs-task-exe-symlink.patch
procfs-task-exe-symlink-fix.patch
procfs-task-exe-symlink-fix-2.patch
free_pidmap-turn-it-into-free_pidmapstruct-upid.patch
put_pid-make-sure-we-dont-free-the-live-pid.patch
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