Re: hwscan hangs on USB2 disk - SCSI_IOCTL_SEND_COMMAND

[Kurt Garloff <garloff@suse.de>]

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Hi Bart,

On Tue, Jun 29, 2004 at 11:37:36AM +0200, Bart Hartgers wrote:
> The problem is that both hwscan and usb-storage get stuck in the 'D"
> state until I unplug the harddisk.
> 
> A strace of hwscan shows:
> 
> 21141 open("/dev/sda", O_RDONLY|O_NONBLOCK) = 3
> 21141 ioctl(3, 0x301, 0xbfffeba0)       = 0
> 21141 ioctl(3, BLKSSZGET, 0xbfffeb9c)   = 0
> 21141 ioctl(3, 0x80041272, 0xbfffeb90)  = 0
> 21141 ioctl(3, FIBMAP, 0xbfffec40)      = 0  <--- hwscan gets stuck here
> 
> The last ioctl corresponds to this bit of code in
> hwinfo-8.38/src/hd/block.c:
> 
> #ifndef SCSI_IOCTL_SEND_COMMAND
> #define SCSI_IOCTL_SEND_COMMAND 1
> #endif
> 
> ...
> 
>       memset(scsi_cmd_buf, 0, sizeof scsi_cmd_buf);
>       // ###### FIXME: smaller!
>       *((unsigned *) (scsi_cmd_buf + 4)) = sizeof scsi_cmd_buf - 0x100;
>       scsi_cmd_buf[8 + 0] = 0x12;
>       scsi_cmd_buf[8 + 1] = 0x01;
>       scsi_cmd_buf[8 + 2] = 0x80;
>       scsi_cmd_buf[8 + 4] = 0xff;
> 
>       k = ioctl(fd, SCSI_IOCTL_SEND_COMMAND, scsi_cmd_buf);
> 
> So it appears that the driver hangs because of a SCSI command. Is this
> kernel bug, and if so, where do I fix it?

To me it looks like a bug in the USB stick.
It probably locks up when you ask for VPD page 0x80 (serial number)
of the device with INQUIRY. 
Some shitty USB devices lock up when you ask for more than 36 bytes
with INQUIRY. See code in scsi_scan.c and the BLIST_INQUIRY_36 and
_58 flags.
Your device may even do so when you don't ask for standard INQUIRY 
data but for EVPD page 0x80 :-(

Does it work if you send the INQUIRY with 36 bytes allocation length?
scsi_cmd_buf[8 + 4] = 0x26;
-- 
Kurt Garloff  <garloff@suse.de>                            Cologne, DE 
SUSE LINUX AG / Novell, Nuernberg, DE               Director SUSE Labs

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