svn commit: r237335 - head/sys/cam/scsi

[Sergey Kandaurov]

On 20 June 2012 22:25, Alexander Motin <mav at freebsd.org> wrote:
> Author: mav
> Date: Wed Jun 20 18:25:51 2012
> New Revision: 237335
> URL: http://svn.freebsd.org/changeset/base/237335
>
> Log:
>  Check status of cam_periph_hold() inside cdclose().  If cd device was
>  invalidated while open, cam_periph_hold() will return error and won't
>  get the reference.  Following reference release will crash the system.
>
>  Sponsored by: iXsystems, Inc.
>  MFC after:    3 days
>
> Modified:
>  head/sys/cam/scsi/scsi_cd.c
>
> Modified: head/sys/cam/scsi/scsi_cd.c
> ==============================================================================
> --- head/sys/cam/scsi/scsi_cd.c Wed Jun 20 18:00:26 2012        (r237334)
> +++ head/sys/cam/scsi/scsi_cd.c Wed Jun 20 18:25:51 2012        (r237335)
> @@ -1041,6 +1041,7 @@ cdclose(struct disk *dp)
>  {
>        struct  cam_periph *periph;
>        struct  cd_softc *softc;
> +       int error;
>
>        periph = (struct cam_periph *)dp->d_drv1;
>        if (periph == NULL)
> @@ -1049,7 +1050,11 @@ cdclose(struct disk *dp)
>        softc = (struct cd_softc *)periph->softc;
>
>        cam_periph_lock(periph);
> -       cam_periph_hold(periph, PRIBIO);
> +       if ((error = cam_periph_hold(periph, PRIBIO)) != 0) {
> +               cam_periph_unlock(periph);
> +               cam_periph_release(periph);
> +               return (0);
> +       }
>
>        CAM_DEBUG(periph->path, CAM_DEBUG_TRACE | CAM_DEBUG_PERIPH,
>            ("cdclose\n"));


Hi.

Does it fix the reported crash with cd refcount underflow? It seems so.
http://lists.freebsd.org/pipermail/freebsd-stable/2012-June/068175.html

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