A small window exists where a tty reopen will observe the tty
just prior to imminent teardown (tty->count == 0); in this case, open()
returns EIO to userspace.
Instead, retry the open after checking for signals and yielding;
this interruptible retry loop allows teardown to commence and initialize
a new tty on retry. Never retry the BSD master pty reopen; there is no
guarantee the pty pair teardown is imminent since the slave file
descriptors may remain open indefinitely.
Signed-off-by: Peter Hurley <pe...@hurleysoftware.com>
---
drivers/tty/tty_io.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index eb391d4..09e8d4f 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1465,13 +1465,13 @@ static int tty_reopen(struct tty_struct *tty)
{
struct tty_driver *driver = tty->driver;
- if (!tty->count)
- return -EIO;
-
if (driver->type == TTY_DRIVER_TYPE_PTY &&
driver->subtype == PTY_TYPE_MASTER)
return -EIO;
+ if (!tty->count)
+ return -EAGAIN;
+
if (test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN))
return -EBUSY;
@@ -2095,8 +2095,13 @@ retry_open:
tty = tty_open_by_driver(device, inode, filp);
if (IS_ERR(tty)) {
+ tty_free_file(filp);
retval = PTR_ERR(tty);
- goto err_file;
+ if (retval != -EAGAIN || signal_pending(current))
+ return retval;
+
+ schedule();
+ goto retry_open;
}
tty_add_file(tty, filp);
@@ -2165,9 +2170,6 @@ retry_open:
read_unlock(&tasklist_lock);
tty_unlock(tty);
return 0;
-err_file:
- tty_free_file(filp);
- return retval;
}
--
2.6.3
--
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