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| author | Peter Hurley <peter@hurleysoftware.com> | 2014-10-16 13:51:30 -0400 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2014-11-23 10:55:47 +0100 |
| commit | 26967a02542d7e0673f82bc1b71e467f37e0f858 (patch) | |
| tree | d663a95a429532c8a694bef954d69f2cf6d61b8b /drivers | |
| parent | 237d7b2521815c41c245ca22219f4cca2ec75058 (diff) | |
| download | linux-26967a02542d7e0673f82bc1b71e467f37e0f858.tar.gz linux-26967a02542d7e0673f82bc1b71e467f37e0f858.tar.bz2 linux-26967a02542d7e0673f82bc1b71e467f37e0f858.zip | |
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>
Diffstat (limited to 'drivers')
| -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 123cedf62cce..cbdd1698c07b 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; } /* |