diff options
| -rw-r--r-- | drivers/tty/n_tty.c | 6 | ||||
| -rw-r--r-- | drivers/tty/tty_io.c | 9 | ||||
| -rw-r--r-- | include/linux/tty.h | 1 |
3 files changed, 16 insertions, 0 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index faf50df81622..1c70541a1467 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -2182,6 +2182,12 @@ 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 fb9bada5f1d5..4ee0a9de7556 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -709,6 +709,14 @@ 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 */ @@ -763,6 +771,7 @@ 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 a41244fe58d0..6f1ee8528210 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -355,6 +355,7 @@ 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 */ |