[PATCH] tty: stop the tty vanishing under procfs access

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 0b615d62a159b16eb8da4a593b52f4a469f46cc4..c0e554971df01dbac80e057bde18b94e6648faa9 100644 (file)
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -347,6 +347,8 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
        sigemptyset(&sigign);
        sigemptyset(&sigcatch);
        cutime = cstime = utime = stime = cputime_zero;
+
+       mutex_lock(&tty_mutex);
        read_lock(&tasklist_lock);
        if (task->sighand) {
                spin_lock_irq(&task->sighand->siglock);
@@ -388,6 +390,7 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole)
        }
        ppid = pid_alive(task) ? task->group_leader->real_parent->tgid : 0;
        read_unlock(&tasklist_lock);
+       mutex_unlock(&tty_mutex);
 
        if (!whole || num_threads<2)
                wchan = get_wchan(task);