diff options
| author | Pan Xinhui <xinhuix.pan@intel.com> | 2015-03-28 10:42:56 +0800 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-06-10 13:42:22 -0400 |
| commit | 32c5ba5c6ec79e3196215ef849a3b2a6047c9cb5 (patch) | |
| tree | bfa0735f0a313ed416c3aac9f5995bf1f779b037 | |
| parent | 526639cb205517c4c83f7aef7884f00415990f3f (diff) | |
tty/n_gsm.c: fix a memory leak when gsmtty is removed
[ Upstream commit 8f9cfeed3eae86c70d3b04445a6f2036b27b6304 ]
when gsmtty_remove put dlci, it will cause memory leak if dlci->port's refcount is zero.
So we do the cleanup work in .cleanup callback instead.
dlci will be last put in two call chains.
1) gsmld_close -> gsm_cleanup_mux -> gsm_dlci_release -> dlci_put
2) gsmld_remove -> dlci_put
so there is a race. the memory leak depends on the race.
In call chain 2. we hit the memory leak. below comment tells.
release_tty -> tty_driver_remove_tty -> gsmtty_remove -> dlci_put -> tty_port_destructor (WARN_ON(port->itty) and return directly)
|
tty->port->itty = NULL;
|
tty_kref_put ---> release_one_tty -> gsmtty_cleanup (added by our patch)
So our patch fix the memory leak by doing the cleanup work after tty core did.
Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com>
Fixes: dfabf7ffa30585
Cc: stable <stable@vger.kernel.org> # 3.14+
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
| -rw-r--r-- | drivers/tty/n_gsm.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index c4343764cc5b..bce16e405d59 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -3170,7 +3170,7 @@ 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 gsmtty_cleanup(struct tty_struct *tty) { struct gsm_dlci *dlci = tty->driver_data; struct gsm_mux *gsm = dlci->gsm; @@ -3178,7 +3178,6 @@ static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty) dlci_put(dlci); dlci_put(gsm->dlci[0]); mux_put(gsm); - driver->ttys[tty->index] = NULL; } /* Virtual ttys for the demux */ @@ -3199,7 +3198,7 @@ static const struct tty_operations gsmtty_ops = { .tiocmget = gsmtty_tiocmget, .tiocmset = gsmtty_tiocmset, .break_ctl = gsmtty_break_ctl, - .remove = gsmtty_remove, + .cleanup = gsmtty_cleanup, }; |