3.2.65-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Peter Hurley <pe...@hurleysoftware.com>
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: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
drivers/tty/tty_io.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1594,6 +1594,7 @@ int tty_release(struct inode *inode, str
int devpts;
int idx;
char buf[64];
+ long timeout = 0;
if (tty_paranoia_check(tty, inode, "tty_release_dev"))
return 0;
@@ -1721,7 +1722,11 @@ int tty_release(struct inode *inode, str
"active!\n", tty_name(tty, buf));
tty_unlock();
mutex_unlock(&tty_mutex);
- schedule();
+ schedule_timeout_killable(timeout);
+ if (timeout < 120 * HZ)
+ timeout = 2 * timeout + 1;
+ else
+ timeout = MAX_SCHEDULE_TIMEOUT;
}
/*
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