summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--drivers/tty/n_tty.c6
-rw-r--r--drivers/tty/tty_io.c9
-rw-r--r--include/linux/tty.h1
3 files changed, 16 insertions, 0 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 5c0e59e8fe46..cbe98bc2b998 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2180,6 +2180,12 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
}
if (tty_hung_up_p(file))
break;
+ /*
+ * Abort readers for ttys which never actually
+ * get hung up. See __tty_hangup().
+ */
+ if (test_bit(TTY_HUPPING, &tty->flags))
+ break;
if (!timeout)
break;
if (file->f_flags & O_NONBLOCK) {
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index eb9133b472f4..63114ea35ec1 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -586,6 +586,14 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
return;
}
+ /*
+ * Some console devices aren't actually hung up for technical and
+ * historical reasons, which can lead to indefinite interruptible
+ * sleep in n_tty_read(). The following explicitly tells
+ * n_tty_read() to abort readers.
+ */
+ set_bit(TTY_HUPPING, &tty->flags);
+
/* inuse_filps is protected by the single tty lock,
this really needs to change if we want to flush the
workqueue with the lock held */
@@ -640,6 +648,7 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
* from the ldisc side, which is now guaranteed.
*/
set_bit(TTY_HUPPED, &tty->flags);
+ clear_bit(TTY_HUPPING, &tty->flags);
tty_unlock(tty);
if (f)
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 0a6c71e0ad01..47f8af22f216 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -364,6 +364,7 @@ struct tty_file_private {
#define TTY_PTY_LOCK 16 /* pty private */
#define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */
#define TTY_HUPPED 18 /* Post driver->hangup() */
+#define TTY_HUPPING 19 /* Hangup in progress */
#define TTY_LDISC_HALTED 22 /* Line discipline is halted */
/* Values for tty->flow_change */