diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-10-16 13:51:30 -0400 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2015-02-02 17:05:15 +0800 |
| commit | 26bc3aa52a38602cc5a4430571d90e158430573b (patch) | |
| tree | de4302f6dd39d1ce61432f554dbb6cfa1b4f3866 | |
| parent | 741946cf911c1ea1cefcf790baaeb618b0712d0f (diff) | |
tty: Fix high cpu load if tty is unreleaseable
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 <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zefan Li <lizefan@huawei.com>
| -rw-r--r-- | drivers/tty/tty_io.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index b28d6356a142..2d66beed3e1f 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1633,6 +1633,7 @@ int tty_release(struct inode *inode, struct file *filp) int devpts; int idx; char buf[64]; + long timeout = 0; if (tty_paranoia_check(tty, inode, __func__)) return 0; @@ -1717,7 +1718,11 @@ int tty_release(struct inode *inode, struct file *filp) __func__, 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; } /* |