From: Peter Hurley <pe...@hurleysoftware.com>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 37b164578826406a173ca7c20d9ba7430134d23e upstream.
Kernel oops can cause the tty to be unreleaseable (for example, if
n_tty_read() crashes while on the read_wait queue). This will cause
tty_release() to endlessly loop without sleeping.
Use a killable sleep timeout which grows by 2n+1 jiffies over the interval
[0, 120 secs.) and then jumps to forever (but still killable).
NB: killable just allows for the task to be rewoken manually, not
to be terminated.
Signed-off-by: Peter Hurley <pe...@hurleysoftware.com>
Signed-off-by: Jiri Slaby <jsl...@suse.cz>
---
drivers/tty/tty_io.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index d3448a90f0f9..25d07412e08e 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1701,6 +1701,7 @@ int tty_release(struct inode *inode, struct file *filp)
int pty_master, tty_closing, o_tty_closing, do_sleep;
int idx;
char buf[64];
+ long timeout = 0;
if (tty_paranoia_check(tty, inode, __func__))
return 0;
@@ -1785,7 +1786,11 @@ int tty_release(struct inode *inode, struct file *filp)
__func__, tty_name(tty, buf));
tty_unlock_pair(tty, o_tty);
mutex_unlock(&tty_mutex);
- schedule();
+ schedule_timeout_killable(timeout);
+ if (timeout < 120 * HZ)
+ timeout = 2 * timeout + 1;
+ else
+ timeout = MAX_SCHEDULE_TIMEOUT;
}
/*
--
2.1.3
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
