Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755654Ab1BORQZ (ORCPT ); Tue, 15 Feb 2011 12:16:25 -0500 Received: from mail-yi0-f46.google.com ([209.85.218.46]:49274 "EHLO mail-yi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345Ab1BORQV (ORCPT ); Tue, 15 Feb 2011 12:16:21 -0500 Message-ID: <4D5AB48A.2040504@ru.mvista.com> Date: Tue, 15 Feb 2011 20:14:50 +0300 From: Sergei Shtylyov User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Jiri Slaby CC: gregkh@suse.de, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, jirislaby@gmail.com, Amit Shah , baoyb Subject: Re: [PATCH 1/1] USB: serial/usb_wwan, fix tty NULL dereference References: <1297781707-3985-1-git-send-email-jslaby@suse.cz> In-Reply-To: <1297781707-3985-1-git-send-email-jslaby@suse.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2815 Lines: 71 Hello. Jiri Slaby wrote: > 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 > Cc: Greg Kroah-Hartman > Signed-off-by: Jiri Slaby > --- > drivers/usb/serial/usb_wwan.c | 15 +++++++++------ > 1 files changed, 9 insertions(+), 6 deletions(-) > diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c > index b004b2a..9c014e2 100644 > --- a/drivers/usb/serial/usb_wwan.c > +++ b/drivers/usb/serial/usb_wwan.c > @@ -295,12 +295,15 @@ static void usb_wwan_indat_callback(struct urb *urb) > __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__); Should be {} on the *else* branch too, according to Documentation/CodingStyle... WBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/