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 41dda25da049..190e5dc15738 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -2238,6 +2238,12 @@ 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 a638c1738547..89fd20382ce4 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -702,6 +702,14 @@ 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 */ @@ -757,6 +765,7 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) * can't yet guarantee all that. */ 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 a1042afff99a..d67ceb3f5958 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -342,6 +342,7 @@ 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 */ #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty)) |