While looking through linux-2.4.18pre1/drivers/scsi/ips.c I noticed that
a spin_lock_irq is held while doing a possibly blocking operation.
Can't this code livelock on SMP if datasize is set?
linux-2.4.18pre1/drivers/scsi/ips.c
1778 /* reobtain the lock */
1779 spin_lock_irq(&io_request_lock);
1780
1781 /* command finished -- copy back */
1782 user_area = *((char **) &SC->cmnd[4]);
1783 kern_area = ha->ioctl_data;
1784 datasize = *((u_int32_t *) &SC->cmnd[8]);
1785
1786 if (datasize) {
1787 if (copy_to_user(user_area, kern_area, datasize) > 0) {
1788 DEBUG_VAR(1, "(%s%d) passthru failed - unable to
copy out user data",
1789 ips_name, ha->host_num);
I am not subscribed to this list, so please CC me.
Petter Wahlman
On Thu, Jan 03 2002, petter wahlman wrote:
>
> While looking through linux-2.4.18pre1/drivers/scsi/ips.c I noticed that
> a spin_lock_irq is held while doing a possibly blocking operation.
> Can't this code livelock on SMP if datasize is set?
>
> linux-2.4.18pre1/drivers/scsi/ips.c
>
> 1778 /* reobtain the lock */
> 1779 spin_lock_irq(&io_request_lock);
> 1780
> 1781 /* command finished -- copy back */
> 1782 user_area = *((char **) &SC->cmnd[4]);
> 1783 kern_area = ha->ioctl_data;
> 1784 datasize = *((u_int32_t *) &SC->cmnd[8]);
> 1785
> 1786 if (datasize) {
> 1787 if (copy_to_user(user_area, kern_area, datasize) > 0) {
> 1788 DEBUG_VAR(1, "(%s%d) passthru failed - unable to
> copy out user data",
> 1789 ips_name, ha->host_num);
>
>
> I am not subscribed to this list, so please CC me.
Yup, that's surely a nasty bug.
--
Jens Axboe
Sorry for the delayed response. We have been snow-bound and shut-down
here for several days. We will address this immediately. Thanks for
bringing it to our attention.
Jens Axboe
<[email protected] To: petter wahlman <[email protected]>
> cc: [email protected], ServeRAID For
Linux/Raleigh/IBM@IBMUS
01/03/2002 Subject: Re: bug in IBM ServeRAID driver?
03:06 PM
On Thu, Jan 03 2002, petter wahlman wrote:
>
> While looking through linux-2.4.18pre1/drivers/scsi/ips.c I noticed that
> a spin_lock_irq is held while doing a possibly blocking operation.
> Can't this code livelock on SMP if datasize is set?
>
> linux-2.4.18pre1/drivers/scsi/ips.c
>
> 1778 /* reobtain the lock */
> 1779 spin_lock_irq(&io_request_lock);
> 1780
> 1781 /* command finished -- copy back */
> 1782 user_area = *((char **) &SC->cmnd[4]);
> 1783 kern_area = ha->ioctl_data;
> 1784 datasize = *((u_int32_t *) &SC->cmnd[8]);
> 1785
> 1786 if (datasize) {
> 1787 if (copy_to_user(user_area, kern_area, datasize) > 0) {
> 1788 DEBUG_VAR(1, "(%s%d) passthru failed - unable to
> copy out user data",
> 1789 ips_name, ha->host_num);
>
>
> I am not subscribed to this list, so please CC me.
Yup, that's surely a nasty bug.
--
Jens Axboe