Re: [PATCH] sd: fix infinite kernel/udev loop on non-removableMedium Not Present

From: James Bottomley
Date: Fri Apr 12 2013 - 16:53:34 EST


Could you resend this, cc'ing the linux-scsi@xxxxxxxxxxxxxxx mailing
list?

Thanks,

James


On Fri, 2013-04-12 at 15:44 -0500, Steve Magnani wrote:
> Commit eface65c336eff420d70beb0fb6787a732e05ffb (2.6.38) altered
> set_media_not_present() in a way that prevents the sd driver from
> remembering that a non-removable device has reported "Medium Not Present".
> This condition can occur on hotplug of a (i.e.) USB Mass Storage device
> whose medium is offline due to an unrecoverable controller error,
> but which is otherwise capable of SCSI communication (to download new
> microcode, etc.).
>
> Under these conditions, the changed code results in an infinite loop
> between the kernel and udevd. When udevd attempts to open the device
> in response to a change notification, a SCSI "Medium Not Present" error
> occurs which causes the kernel to signal another change. The cycle
> repeats until the device is unplugged, resulting in udevd consuming ever-
> increasing amounts of CPU and virtual memory.
>
> Resolve this by remembering "media not present" whether the device has
> declared itself "removable" or not.
>
> Signed-off-by: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>
> ---
> --- a/drivers/scsi/sd.c 2013-04-12 14:16:12.252531097 -0500
> +++ b/drivers/scsi/sd.c 2013-04-12 14:21:55.197216521 -0500
> @@ -1298,10 +1298,8 @@ out:
>
> static void set_media_not_present(struct scsi_disk *sdkp)
> {
> - if (sdkp->media_present)
> + if (sdkp->media_present) {
> sdkp->device->changed = 1;
> -
> - if (sdkp->device->removable) {
> sdkp->media_present = 0;
> sdkp->capacity = 0;
> }
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/