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| author | Peter Hurley <peter@hurleysoftware.com> | 2014-10-16 13:51:30 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-12-14 16:23:55 +0000 |
| commit | 069347b245ac0afe052f68e7f5ea734207f826f4 (patch) | |
| tree | 4c6fff5773bb397b3268a67a43f569cf198b385f /drivers/tty | |
| parent | 2eb38b7609836f81419f52a62170c2a222f7e1aa (diff) | |
| download | kernel_samsung_smdk4412-069347b245ac0afe052f68e7f5ea734207f826f4.zip kernel_samsung_smdk4412-069347b245ac0afe052f68e7f5ea734207f826f4.tar.gz kernel_samsung_smdk4412-069347b245ac0afe052f68e7f5ea734207f826f4.tar.bz2 | |
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: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'drivers/tty')
| -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 446df6b..613f06a 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1594,6 +1594,7 @@ 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, "tty_release_dev")) return 0; @@ -1721,7 +1722,11 @@ int tty_release(struct inode *inode, struct file *filp) "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; } /* |