From 80ea73378af46b0023eb2f400d26c2a60248ffaa Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 9 Feb 2014 20:59:08 -0500 Subject: [PATCH] Bluetooth: Fix unreleased rfcomm_dev reference When RFCOMM_RELEASE_ONHUP is set, the rfcomm tty driver 'takes over' the initial rfcomm_dev reference created by the RFCOMMCREATEDEV ioctl. The assumption is that the rfcomm tty driver will release the rfcomm_dev reference when the tty is freed (in rfcomm_tty_cleanup()). However, if the tty is never opened, the 'take over' never occurs, so when RFCOMMRELEASEDEV ioctl is called, the reference is not released. Track the state of the reference 'take over' so that the release is guaranteed by either the RFCOMMRELEASEDEV ioctl or the rfcomm tty driver. Note that the synchronous hangup in rfcomm_release_dev() ensures that rfcomm_tty_install() cannot race with the RFCOMMRELEASEDEV ioctl. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann --- include/net/bluetooth/rfcomm.h | 1 + net/bluetooth/rfcomm/tty.c | 6 ++++-- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/include/net/bluetooth/rfcomm.h b/include/net/bluetooth/rfcomm.h index b9759eb17cdd..0d69936831fa 100644 --- a/include/net/bluetooth/rfcomm.h +++ b/include/net/bluetooth/rfcomm.h @@ -333,6 +333,7 @@ int rfcomm_connect_ind(struct rfcomm_session *s, u8 channel, /* rfcomm_dev.status bit definitions */ #define RFCOMM_DEV_RELEASED 0 +#define RFCOMM_TTY_OWNED 1 struct rfcomm_dev_req { s16 dev_id; diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c index d9d4bc89e638..bb570d95adca 100644 --- a/net/bluetooth/rfcomm/tty.c +++ b/net/bluetooth/rfcomm/tty.c @@ -441,7 +441,7 @@ static int rfcomm_release_dev(void __user *arg) tty_kref_put(tty); } - if (!test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) + if (!test_bit(RFCOMM_TTY_OWNED, &dev->status)) tty_port_put(&dev->port); tty_port_put(&dev->port); @@ -685,8 +685,10 @@ static int rfcomm_tty_install(struct tty_driver *driver, struct tty_struct *tty) * when the last process closes the tty. The behaviour is expected by * userspace. */ - if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) + if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) { + set_bit(RFCOMM_TTY_OWNED, &dev->status); tty_port_put(&dev->port); + } return 0; } -- GitLab