From 81af8d67d4fc35b1ee6e0feb1f1b34b3a33eeb44 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 2 Oct 2006 02:17:13 -0700 Subject: [PATCH] vt: rework the console spawning variables This is such a rare path it took me a while to figure out how to test this after soring out the locking. This patch does several things. - The variables used are moved into a structure and declared in vt_kern.h - A spinlock is added so we don't have SMP races updating the values. - Instead of raw pid_t value a struct_pid is used to guard against pid wrap around issues, if the daemon to spawn a new console dies. Signed-off-by: Eric W. Biederman Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/vt_ioctl.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'drivers/char/vt_ioctl.c') diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c index a53e382cc10..dc408af165a 100644 --- a/drivers/char/vt_ioctl.c +++ b/drivers/char/vt_ioctl.c @@ -645,13 +645,16 @@ int vt_ioctl(struct tty_struct *tty, struct file * file, */ case KDSIGACCEPT: { - extern int spawnpid, spawnsig; if (!perm || !capable(CAP_KILL)) return -EPERM; if (!valid_signal(arg) || arg < 1 || arg == SIGKILL) return -EINVAL; - spawnpid = current->pid; - spawnsig = arg; + + spin_lock_irq(&vt_spawn_con.lock); + put_pid(vt_spawn_con.pid); + vt_spawn_con.pid = get_pid(task_pid(current)); + vt_spawn_con.sig = arg; + spin_unlock_irq(&vt_spawn_con.lock); return 0; } -- cgit v1.2.3