Re: ftdi_sio BUG: NULL pointer dereference

From: Mike Remski
Date: Mon Jun 02 2014 - 12:02:48 EST

On 06/02/2014 11:40 AM, Johan Hovold wrote:
[ Please avoid top-posting. ]

On Mon, Jun 02, 2014 at 11:16:11AM -0400, Mike Remski wrote:
Thanks Johan, that's why I looked at the cross references for ftdi_sio.c
over on
http://lxr.free-electrons.com/source/drivers/usb/serial/ftdi_sio.c,
latest version it's showing is 3.14. It appears that the ftdi_sio code
is largely the same as in 2.6.32, particularly in the
ftdi_set_max_packet_size() function.
Lots of things have changed since v2.6.32 and not just in the driver
itself but in all the infrastructure it relies on.

I'm trying to verify if the "number of endpoints is 0" is a valid
situation.
No, that is not normal, but it should not crash the driver if it's a
hardware issue. What is the lsusb -v output of your device (make sure
the ftdi_sio driver isn't loaded when connecting the device).

And what happens if you plug it into a machine running a recent kernel?

Thanks,
Johan
Thanks Johan; sorry for top posting.
An even more ancient kernel (2.6.18) has v1.4.3 of the ftdi_sio.c and I do not see this problem. In v1.4.3,
ftdi_sio_attach() is doing the work that is now in ftdi_sio_port_probe(), but 1.4.3 does not have the ftdi_set_max_packet_size() code. The device works fine under 2.6.18. I have to see if I can scrounge up
a machine running a later kernel (other than my desktop).
Should have included this earlier but its unmodified CentOs 6.0 and 6.4, kernel is:

Linux nicA91A84 2.6.32-71.29.1.el6.i686 #1 SMP Tue May 10 17:35:05 CDT 2011 i686 i686 i386 GNU/Linux


lsusb -v cut for the device in question.

Bus 005 Device 003: ID 1fdf:1001
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2 ?
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 64
idVendor 0x1fdf
idProduct 0x1001
bcdDevice 0.03
iManufacturer 1 Sepura
iProduct 2 Colour Console
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 134
bNumInterfaces 4
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 100mA
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 0
bInterfaceCount 2
bFunctionClass 2 Communications
bFunctionSubClass 2 Abstract (modem)
bFunctionProtocol 0 None
iFunction 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 2 Communications
bInterfaceSubClass 2 Abstract (modem)
bInterfaceProtocol 0 None
iInterface 0
CDC Header:
bcdCDC 1.10
CDC Call Management:
bmCapabilities 0x01
call management
bDataInterface 1
CDC ACM:
bmCapabilities 0x02
line coding and serial state
CDC Union:
bMasterInterface 0
bSlaveInterface 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 10
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 10 CDC Data
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Interface Association:
bLength 8
bDescriptorType 11
bFirstInterface 2
bInterfaceCount 2
bFunctionClass 2 Communications
bFunctionSubClass 2 Abstract (modem)
bFunctionProtocol 0 None
iFunction 0
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 2 Communications
bInterfaceSubClass 2 Abstract (modem)
bInterfaceProtocol 0 None
iInterface 0
CDC Header:
bcdCDC 1.10
CDC Call Management:
bmCapabilities 0x01
call management
bDataInterface 3
CDC ACM:
bmCapabilities 0x02
line coding and serial state
CDC Union:
bMasterInterface 2
bSlaveInterface 3
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 3
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 10 CDC Data
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x04 EP 4 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x85 EP 5 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Device Status: 0x0001
Self Powered

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