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Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/tty_io.c19
1 files changed, 11 insertions, 8 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 48b59006afc..63543731977 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -2719,6 +2719,8 @@ static int tty_fasync(int fd, struct file * filp, int on)
* Locking:
* Called functions take tty_ldisc_lock
* current->signal->tty check is safe without locks
+ *
+ * FIXME: may race normal receive processing
*/
static int tiocsti(struct tty_struct *tty, char __user *p)
@@ -2878,9 +2880,7 @@ static int fionbio(struct file *file, int __user *p)
* Locking:
* Takes tasklist lock internally to walk sessions
* Takes task_lock() when updating signal->tty
- *
- * FIXME: tty_mutex is needed to protect signal->tty references.
- * FIXME: why task_lock on the signal->tty reference ??
+ * Takes tty_mutex() to protect tty instance
*
*/
@@ -2915,9 +2915,11 @@ static int tiocsctty(struct tty_struct *tty, int arg)
} else
return -EPERM;
}
+ mutex_lock(&tty_mutex);
task_lock(current);
current->signal->tty = tty;
task_unlock(current);
+ mutex_unlock(&tty_mutex);
current->signal->tty_old_pgrp = 0;
tty->session = current->signal->session;
tty->pgrp = process_group(current);
@@ -2957,8 +2959,6 @@ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
* permitted where the tty session is our session.
*
* Locking: None
- *
- * FIXME: current->signal->tty referencing is unsafe.
*/
static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p)
@@ -3037,19 +3037,20 @@ static int tiocsetd(struct tty_struct *tty, int __user *p)
* timed break functionality.
*
* Locking:
- * None
+ * atomic_write_lock serializes
*
- * FIXME:
- * What if two overlap
*/
static int send_break(struct tty_struct *tty, unsigned int duration)
{
+ if (mutex_lock_interruptible(&tty->atomic_write_lock))
+ return -EINTR;
tty->driver->break_ctl(tty, -1);
if (!signal_pending(current)) {
msleep_interruptible(duration);
}
tty->driver->break_ctl(tty, 0);
+ mutex_unlock(&tty->atomic_write_lock);
if (signal_pending(current))
return -EINTR;
return 0;
@@ -3142,6 +3143,8 @@ int tty_ioctl(struct inode * inode, struct file * file,
if (tty_paranoia_check(tty, inode, "tty_ioctl"))
return -EINVAL;
+ /* CHECKME: is this safe as one end closes ? */
+
real_tty = tty;
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)