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Subject[PATCH] tty/n_gsm.c: fix a memory leak when gsmtty is removed
In gsmtty_remove, we will put dlci. when dlci's ref-count is zero,
tty_port_destructor will be called, and it will check if port->itty is NULL.
However port->itty will be set to NULL in release_tty after gsmtty_remove.
that may cause memory leak. so we use queue_work to put the dlci later.

Signed-off-by: xinhui.pan <xinhuix.pan@intel.com>
---
drivers/tty/n_gsm.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index c434376..50f4660 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -135,6 +135,7 @@ struct gsm_dlci {
#define DLCI_OPEN 2 /* SABM/UA complete */
#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
struct mutex mutex;
+ struct work_struct putself_work;

/* Link layer */
spinlock_t lock; /* Protects the internal state */
@@ -3170,14 +3171,25 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state)
return gsmtty_modem_update(dlci, encode);
}

-static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty)
+static void put_gsm_dlci(struct work_struct *work)
{
- struct gsm_dlci *dlci = tty->driver_data;
+ struct gsm_dlci *dlci =
+ container_of(work, struct gsm_dlci, putself_work);
struct gsm_mux *gsm = dlci->gsm;

+ mutex_lock(&gsm->mutex);
dlci_put(dlci);
dlci_put(gsm->dlci[0]);
+ mutex_unlock(&gsm->mutex);
mux_put(gsm);
+}
+
+static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty)
+{
+ struct gsm_dlci *dlci = tty->driver_data;
+
+ INIT_WORK(&dlci->putself_work, put_gsm_dlci);
+ schedule_work(&dlci->putself_work);
driver->ttys[tty->index] = NULL;
}

--
1.9.1

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