diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2014-10-16 13:51:30 -0400 |
|---|---|---|
| committer | Stefan Bader <stefan.bader@canonical.com> | 2014-11-25 15:20:27 +0100 |
| commit | 38b11fb2fa8a801eb46b00b91e86c912136845d7 (patch) | |
| tree | ba8e6ad1a829cc2d7b4b50f84b027d5b23b60859 | |
| parent | 4094fcd43e385091ad4b494f6e7e56c0e2acbced (diff) | |
| download | linux-2.6.32.y-drm33.z-38b11fb2fa8a801eb46b00b91e86c912136845d7.tar.gz | |
tty: Fix high cpu load if tty is unreleaseable
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.
Cc: <stable@vger.kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 37b164578826406a173ca7c20d9ba7430134d23e)
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
| -rw-r--r-- | drivers/char/tty_io.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 123cedf62ccef..cbdd1698c07b8 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1482,6 +1482,7 @@ void tty_release_dev(struct file *filp) int devpts; int idx; char buf[64]; + long timeout = 0; struct inode *inode; inode = filp->f_path.dentry->d_inode; @@ -1602,7 +1603,11 @@ void tty_release_dev(struct file *filp) printk(KERN_WARNING "tty_release_dev: %s: read/write wait queue " "active!\n", tty_name(tty, buf)); mutex_unlock(&tty_mutex); - schedule(); + schedule_timeout_killable(timeout); + if (timeout < 120 * HZ) + timeout = 2 * timeout + 1; + else + timeout = MAX_SCHEDULE_TIMEOUT; } /* |