From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754286Ab1G0AlZ (ORCPT ); Tue, 26 Jul 2011 20:41:25 -0400 Received: from mga01.intel.com ([192.55.52.88]:6474 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753497Ab1G0AfB (ORCPT ); Tue, 26 Jul 2011 20:35:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,272,1309762800"; d="scan'208";a="34855562" From: Andi Kleen References: <20110726534.972201586@firstfloor.org> In-Reply-To: <20110726534.972201586@firstfloor.org> To: jslaby@suse.cz, amitshah@gmx.net, baoyb@avit.org.cn, stable@kernel.org, gregkh@suse.de, ak@linux.intel.com, linux-kernel@vger.kernel.org, stable@kernel.org, tim.bird@am.sony.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] [9/98] USB: serial/usb_wwan, fix tty NULL dereference Message-Id: <20110727003501.247242403FF@tassilo.jf.intel.com> Date: Tue, 26 Jul 2011 17:35:01 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Slaby [ upstream commit 38237fd2be9421c104f84cc35665097bdce89013 ] tty_port_tty_get may return without any problems NULL. Handle this case and do not oops in usb_wwan_indat_callback by dereferencing it. The oops: Unable to handle kernel paging request for data at address 0x000000d8 Faulting instruction address: 0xc0175b3c Oops: Kernel access of bad area, sig: 11 [#1] PowerPC 40x Platform last sysfs file: /sys/devices/pci0000:00/0000:00:00.0/0000:01:00.0/0000:02:09.2/usb1/idVendor Modules linked in: NIP: c0175b3c LR: c0175e7c CTR: c0215c90 REGS: c77f7d50 TRAP: 0300 Not tainted (2.6.37-rc5) MSR: 00021030 CR: 88482028 XER: 2000005f DEAR: 000000d8, ESR: 00000000 TASK = c7141b90[1149] 'wvdial' THREAD: c2750000 GPR00: 00021030 c77f7e00 c7141b90 00000000 0000000e 00000000 0000000e c0410680 GPR08: c683db00 00000000 00000001 c03c81f8 88482028 10073ef4 ffffffb9 ffffff94 GPR16: 00000000 fde036c0 00200200 00100100 00000001 ffffff8d c34fabcc 00000000 GPR24: c71120d4 00000000 00000000 0000000e 00021030 00000000 00000000 0000000e NIP [c0175b3c] tty_buffer_request_room+0x2c/0x194 LR [c0175e7c] tty_insert_flip_string_fixed_flag+0x3c/0xb0 Call Trace: [c77f7e00] [00000003] 0x3 (unreliable) [c77f7e30] [c0175e7c] tty_insert_flip_string_fixed_flag+0x3c/0xb0 [c77f7e60] [c0215df4] usb_wwan_indat_callback+0x164/0x170 ... References: https://bugzilla.kernel.org/show_bug.cgi?id=24582 Cc: Amit Shah Cc: baoyb Signed-off-by: Jiri Slaby Cc: stable Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen Index: linux-2.6.35.y/drivers/usb/serial/usb_wwan.c =================================================================== --- linux-2.6.35.y.orig/drivers/usb/serial/usb_wwan.c +++ linux-2.6.35.y/drivers/usb/serial/usb_wwan.c @@ -216,12 +216,15 @@ static void usb_wwan_indat_callback(stru __func__, status, endpoint); } else { tty = tty_port_tty_get(&port->port); - if (urb->actual_length) { - tty_insert_flip_string(tty, data, urb->actual_length); - tty_flip_buffer_push(tty); - } else - dbg("%s: empty read urb received", __func__); - tty_kref_put(tty); + if (tty) { + if (urb->actual_length) { + tty_insert_flip_string(tty, data, + urb->actual_length); + tty_flip_buffer_push(tty); + } else + dbg("%s: empty read urb received", __func__); + tty_kref_put(tty); + } /* Resubmit urb so we continue receiving */ if (status != -ESHUTDOWN) {