Re: [PATCH] Oops in usb-storage.c

Matthew Dharm
2001-10-17T01:01:23Z

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Actually, this is a side-effect of another problem, which is that INQUIRY
is legal for a device at any time (at least, to SCSI). What we really need
to do is fake an INQURIY response for detached devices, separate from also
those devices which need a faked-inquiry all the time.

Matt

On Wed, Oct 17, 2001 at 12:58:22AM +0200, Jan Niehusmann wrote:
> Hi,
>
> usb-storage.c oopses in fill_inquiry_response if I send an INQUIRY
> to device which is currently disconnected from the USB bus.
>
> This happens because fill_inquiry_response is called outside a
> check for us->pusb_dev. Moving the special case into the if()
> block, the oops is fixed.
>
> (For reference, the oops is below the patch)
>
> Jan
>
> --- linux-2.4.12-ac3/drivers/usb/storage/usb.c.orig Mon Oct 1 12:15:29 2001
> +++ linux-2.4.12-ac3/drivers/usb/storage/usb.c Wed Oct 17 00:33:22 2001
> @@ -389,24 +389,6 @@
> break;
> }
>
> - /* Handle those devices which need us to fake their
> - * inquiry data */
> - if ((us->srb->cmnd[0] == INQUIRY) &&
> - (us->flags & US_FL_FIX_INQUIRY)) {
> - unsigned char data_ptr[36] = {
> - 0x00, 0x80, 0x02, 0x02,
> - 0x1F, 0x00, 0x00, 0x00};
> -
> - US_DEBUGP("Faking INQUIRY command\n");
> - fill_inquiry_response(us, data_ptr, 36);
> - us->srb->result = GOOD << 1;
> -
> - set_current_state(TASK_INTERRUPTIBLE);
> - us->srb->scsi_done(us->srb);
> - us->srb = NULL;
> - break;
> - }
> -
> /* lock the device pointers */
> down(&(us->dev_semaphore));
>
> @@ -423,15 +405,30 @@
> sizeof(usb_stor_sense_notready));
> us->srb->result = GOOD << 1;
> } else {
> + memset(us->srb->request_buffer, 0, us->srb->request_bufflen);
> memcpy(us->srb->sense_buffer,
> usb_stor_sense_notready,
> sizeof(usb_stor_sense_notready));
> us->srb->result = CHECK_CONDITION << 1;
> }
> } else { /* !us->pusb_dev */
> - /* we've got a command, let's do it! */
> - US_DEBUG(usb_stor_show_command(us->srb));
> - us->proto_handler(us->srb, us);
> +
> + /* Handle those devices which need us to fake
> + * their inquiry data */
> + if ((us->srb->cmnd[0] == INQUIRY) &&
> + (us->flags & US_FL_FIX_INQUIRY)) {
> + unsigned char data_ptr[36] = {
> + 0x00, 0x80, 0x02, 0x02,
> + 0x1F, 0x00, 0x00, 0x00};
> +
> + US_DEBUGP("Faking INQUIRY command\n");
> + fill_inquiry_response(us, data_ptr, 36);
> + us->srb->result = GOOD << 1;
> + } else {
> + /* we've got a command, let's do it! */
> + US_DEBUG(usb_stor_show_command(us->srb));
> + us->proto_handler(us->srb, us);
> + }
> }
>
> /* unlock the device pointers */
>
>
>
>
> Oct 16 21:07:28 sirith kernel: Oops: 0000
> Oct 16 21:07:28 sirith kernel: CPU: 0
> Oct 16 21:07:28 sirith kernel: EIP: 0010:[<e4951766>] Tainted: P
> Oct 16 21:07:28 sirith kernel: EFLAGS: 00010246
> Oct 16 21:07:28 sirith kernel: eax: 00000000 ebx: dc636600 ecx: 00000000 edx: 00000010
> Oct 16 21:07:28 sirith kernel: esi: e495d460 edi: d9f09fcc ebp: e495d450 esp: d9f09f7c
> Oct 16 21:07:28 sirith kernel: ds: 0018 es: 0018 ss: 0018
> Oct 16 21:07:28 sirith kernel: Process usb-storage-0 (pid: 766, stackpage=d9f09000)
> Oct 16 21:07:28 sirith kernel: Stack: d9f08000 e495da91 d9f09ff0 dc636600 c0116373 c02955a7 00000005 c01162c4
> Oct 16 21:07:28 sirith kernel: d9f08000 e4951b44 dc636600 d9f09fcc 00000024 e495daa0 00000100 da003dcc
> Oct 16 21:07:28 sirith kernel: dc636600 dc636600 dc636604 00000001 02028000 0000001f 69736143 0000006f
> Oct 16 21:07:28 sirith kernel: Call Trace: [<e495da91>] [release_console_sem+115/128] [printk+260/272] [<e4951b44>] [<e495daa0>]
> Oct 16 21:07:28 sirith kernel: Code: 0f b7 80 cc 00 00 00 66 c1 e8 0c 0c 30 88 47 20 8b 43 18 8a
>
> >>EIP; e4951766 <[usb-storage]fill_inquiry_response+116/2f0> <=====
> Trace; e495da90 <[usb-storage]__module_usb_device_size+670/81be>
> Code; e4951766 <[usb-storage]fill_inquiry_response+116/2f0>
> 00000000 <_EIP>:
> Code; e4951766 <[usb-storage]fill_inquiry_response+116/2f0> <=====
> 0: 0f b7 80 cc 00 00 00 movzwl 0xcc(%eax),%eax <=====
> Code; e495176c <[usb-storage]fill_inquiry_response+11c/2f0>
> 7: 66 c1 e8 0c shr $0xc,%ax
> Code; e4951770 <[usb-storage]fill_inquiry_response+120/2f0>
> b: 0c 30 or $0x30,%al
> Code; e4951772 <[usb-storage]fill_inquiry_response+122/2f0>
> d: 88 47 20 mov %al,0x20(%edi)
> Code; e4951776 <[usb-storage]fill_inquiry_response+126/2f0>
> 10: 8b 43 18 mov 0x18(%ebx),%eax
> Code; e4951778 <[usb-storage]fill_inquiry_response+128/2f0>
> 13: 8a 00 mov (%eax),%al

--
Matthew Dharm Home: mdharm-usb@one-eyed-alien.net
Maintainer, Linux USB Mass Storage Driver

Sir, for the hundreth time, we do NOT carry 600-round boxes of belt-fed
suction darts!
-- Salesperson to Greg
User Friendly, 12/30/1997

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