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 <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__); + tty_kref_put(tty); + } /* Resubmit urb so we continue receiving */ if (status != -ESHUTDOWN) { -- 1.7.3.4 -- 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
