4.5-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jiri Slaby <jsl...@suse.cz> commit d175feca89a1c162f60f4e3560ca7bc9437c65eb upstream. Dmitry reported, that the current cleanup code in n_gsm can trigger a warning: WARNING: CPU: 2 PID: 24238 at drivers/tty/n_gsm.c:2048 gsm_cleanup_mux+0x166/0x6b0() ... Call Trace: ... [<ffffffff81247ab9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:490 [<ffffffff828d0456>] gsm_cleanup_mux+0x166/0x6b0 drivers/tty/n_gsm.c:2048 [<ffffffff828d4d87>] gsmld_open+0x5b7/0x7a0 drivers/tty/n_gsm.c:2386 [<ffffffff828b9078>] tty_ldisc_open.isra.2+0x78/0xd0 drivers/tty/tty_ldisc.c:447 [<ffffffff828b973a>] tty_set_ldisc+0x1ca/0xa70 drivers/tty/tty_ldisc.c:567 [< inline >] tiocsetd drivers/tty/tty_io.c:2650 [<ffffffff828a14ea>] tty_ioctl+0xb2a/0x2140 drivers/tty/tty_io.c:2883 ... But this is a legal path when open fails to find a space in the gsm_mux array and tries to clean up. So make it a standard test instead of a warning. Reported-by: "Dmitry Vyukov" <dvyu...@google.com> Cc: Alan Cox <a...@linux.intel.com> Link: http://lkml.kernel.org/r/cact4y+bhqbab68vfi7romcs-z9zw3kqrvcq+bvhh1oa5nca...@mail.gmail.com Fixes: 5a640967 ("tty/n_gsm.c: fix a memory leak in gsmld_open()") Signed-off-by: Jiri Slaby <jsl...@suse.cz> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/tty/n_gsm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2045,7 +2045,9 @@ static void gsm_cleanup_mux(struct gsm_m } } spin_unlock(&gsm_mux_lock); - WARN_ON(i == MAX_MUX); + /* open failed before registering => nothing to do */ + if (i == MAX_MUX) + return; /* In theory disconnecting DLCI 0 is sufficient but for some modems this is apparently not the case. */
