On 02/15/2011 07:10 PM, Amit Shah wrote: > On (Tue) 15 Feb 2011 [20:14:50], Sergei Shtylyov wrote: >> 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. > > Thanks for looking at this! > >>> 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 <ME,CE,IR,DR> 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 <amitshah@xxxxxxx> >>> Cc: baoyb <baoyb@xxxxxxxxxxx> >>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxx> >>> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> >>> --- >>> 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... > > If you're fixing that, might as well return in the 'if' above No, the urb has to be resubmitted. regards, -- js -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
