From 9c9f4ded90a59eee84e15f5fd38c03d60184e112 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Mon, 13 Oct 2008 10:37:26 +0100 Subject: tty: Add a kref count Introduce a kref to the tty structure and use it to protect the tty->signal tty references. For now we don't introduce it for anything else. Signed-off-by: Alan Cox Signed-off-by: Linus Torvalds --- kernel/fork.c | 5 ++++- kernel/sys.c | 4 +--- 2 files changed, 5 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/fork.c b/kernel/fork.c index 7ce2ebe84796..30de644a40c4 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -802,6 +802,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) sig->leader = 0; /* session leadership doesn't inherit */ sig->tty_old_pgrp = NULL; + sig->tty = NULL; sig->utime = sig->stime = sig->cutime = sig->cstime = cputime_zero; sig->gtime = cputime_zero; @@ -838,6 +839,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) void __cleanup_signal(struct signal_struct *sig) { exit_thread_group_keys(sig); + tty_kref_put(sig->tty); kmem_cache_free(signal_cachep, sig); } @@ -1227,7 +1229,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, p->nsproxy->pid_ns->child_reaper = p; p->signal->leader_pid = pid; - p->signal->tty = current->signal->tty; + tty_kref_put(p->signal->tty); + p->signal->tty = tty_kref_get(current->signal->tty); set_task_pgrp(p, task_pgrp_nr(current)); set_task_session(p, task_session_nr(current)); attach_pid(p, PIDTYPE_PGID, task_pgrp(current)); diff --git a/kernel/sys.c b/kernel/sys.c index 038a7bc0901d..234d9454294e 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1060,9 +1060,7 @@ asmlinkage long sys_setsid(void) group_leader->signal->leader = 1; __set_special_pids(sid); - spin_lock(&group_leader->sighand->siglock); - group_leader->signal->tty = NULL; - spin_unlock(&group_leader->sighand->siglock); + proc_clear_tty(group_leader); err = session; out: -- cgit v1.2.3