From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52049 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933607AbcE3UcC (ORCPT ); Mon, 30 May 2016 16:32:02 -0400 Subject: Patch "TTY: n_gsm, fix false positive WARN_ON" has been added to the 4.6-stable tree To: jslaby@suse.cz, alan@linux.intel.com, dvyukov@google.com, gregkh@linuxfoundation.org Cc: , From: Date: Mon, 30 May 2016 13:24:40 -0700 Message-ID: <146463988018196@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled TTY: n_gsm, fix false positive WARN_ON to the 4.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tty-n_gsm-fix-false-positive-warn_on.patch and it can be found in the queue-4.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From d175feca89a1c162f60f4e3560ca7bc9437c65eb Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Tue, 22 Mar 2016 18:09:51 +0100 Subject: TTY: n_gsm, fix false positive WARN_ON From: Jiri Slaby 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: ... [] warn_slowpath_null+0x29/0x30 kernel/panic.c:490 [] gsm_cleanup_mux+0x166/0x6b0 drivers/tty/n_gsm.c:2048 [] gsmld_open+0x5b7/0x7a0 drivers/tty/n_gsm.c:2386 [] tty_ldisc_open.isra.2+0x78/0xd0 drivers/tty/tty_ldisc.c:447 [] tty_set_ldisc+0x1ca/0xa70 drivers/tty/tty_ldisc.c:567 [< inline >] tiocsetd drivers/tty/tty_io.c:2650 [] 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" Cc: Alan Cox Link: http://lkml.kernel.org/r/CACT4Y+bHQbAB68VFi7Romcs-Z9ZW3kQRvcq+BvHH1oa5NcAdLA@mail.gmail.com Fixes: 5a640967 ("tty/n_gsm.c: fix a memory leak in gsmld_open()") Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- 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. */ Patches currently in stable-queue which might be from jslaby@suse.cz are queue-4.6/bluetooth-vhci-purge-unhandled-skbs.patch queue-4.6/tty-n_gsm-fix-false-positive-warn_on.patch queue-4.6/bluetooth-vhci-fix-open_timeout-vs.-hdev-race.patch queue-4.6/tty-vt-return-error-when-con_startup-fails.patch