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authorOleg Nesterov <oleg@tv-sign.ru>2008-04-30 00:53:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 08:29:37 -0700
commit7a5e873f096e04e6d8719e4ecb7b70d2decca503 (patch)
tree2d3f7cc6c15e03de02484f9d754a9174ce2fff76 /fs/exec.c
parentfae5fa44f1fd079ffbed8e0add929dd7bbd1347f (diff)
downloadlinux-7a5e873f096e04e6d8719e4ecb7b70d2decca503.tar.gz
signals: de_thread: simplify the ->child_reaper switching
Now that we rely on SIGNAL_UNKILLABLE flag, de_thread() doesn't need the nasty
hack to kill the old ->child_reaper during the mt-exec.

This also means we can avoid taking tasklist_lock around zap_other_threads().

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c15
1 files changed, 2 insertions, 13 deletions
diff --git a/fs/exec.c b/fs/exec.c
index a13883903ee9..8fccc276d40d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -766,9 +766,7 @@ static int de_thread(struct task_struct *tsk)
 
 	/*
 	 * Kill all other threads in the thread group.
-	 * We must hold tasklist_lock to call zap_other_threads.
 	 */
-	read_lock(&tasklist_lock);
 	spin_lock_irq(lock);
 	if (signal_group_exit(sig)) {
 		/*
@@ -776,21 +774,10 @@ static int de_thread(struct task_struct *tsk)
 		 * return so that the signal is processed.
 		 */
 		spin_unlock_irq(lock);
-		read_unlock(&tasklist_lock);
 		return -EAGAIN;
 	}
-
-	/*
-	 * child_reaper ignores SIGKILL, change it now.
-	 * Reparenting needs write_lock on tasklist_lock,
-	 * so it is safe to do it under read_lock.
-	 */
-	if (unlikely(tsk->group_leader == task_child_reaper(tsk)))
-		task_active_pid_ns(tsk)->child_reaper = tsk;
-
 	sig->group_exit_task = tsk;
 	zap_other_threads(tsk);
-	read_unlock(&tasklist_lock);
 
 	/* Account for the thread group leader hanging around: */
 	count = thread_group_leader(tsk) ? 1 : 2;
@@ -821,6 +808,8 @@ static int de_thread(struct task_struct *tsk)
 			schedule();
 		}
 
+		if (unlikely(task_child_reaper(tsk) == leader))
+			task_active_pid_ns(tsk)->child_reaper = tsk;
 		/*
 		 * The only record we have of the real-time age of a
 		 * process, regardless of execs it's done, is start_time.