[RTEMS Project] #1272: [libblock, bdbuf] disk released early

[RTEMS trac]

#1272: [libblock, bdbuf] disk released early
----------------------+----------------------------
 Reporter:  strauman  |       Owner:  joel.sherrill
     Type:  defect    |      Status:  closed
 Priority:  normal    |   Milestone:  4.9
Component:  cpukit    |     Version:  4.7
 Severity:  normal    |  Resolution:  fixed
 Keywords:            |
----------------------+----------------------------
Description changed by chrisj:

Old description:

> A long time ago, Eugeny Mints reported
> (http://www.rtems.org/ml/rtems-users/2002/october/msg00041.html)
>
> >But you remaind me about bug in rtems_bdbuf_get - there
> >rtems_disk_release(dd) call rigth befor DISABLE_PREEMPTION
> >is
> >wrong because pdd pointer which is used  later in ioctl may
> >be null if between rtems_disk_release(dd)
> >call and DISABLE_PREEMPTION some high priority task removed
> >both devices (pointed by dd and pdd). This bug may be fixed
> >by simply moving rtems_disk_release(dd) call below
> >find_or_assign_buffer(pdd, block, &bd_buf) call.
> >The same was in rtems_bdbuf_read but I fixed it in this
> >routine but forgot about rtems_bdbuf_get :(
>
> The attached patch fixes this issue.
>
> Also, releasing the disk was moved after re-enabling task preemption
> (for consistency; other routines in bdbuf.c also re-enable task
> preemption prior to releasing the disk)

New description:

 A long time ago, Eugeny Mints reported
 (http://lists.rtems.org/pipermail/users/2002-October/005740.html)

 >But you remaind me about bug in rtems_bdbuf_get - there
 >rtems_disk_release(dd) call rigth befor DISABLE_PREEMPTION
 >is
 >wrong because pdd pointer which is used  later in ioctl may
 >be null if between rtems_disk_release(dd)
 >call and DISABLE_PREEMPTION some high priority task removed
 >both devices (pointed by dd and pdd). This bug may be fixed
 >by simply moving rtems_disk_release(dd) call below
 >find_or_assign_buffer(pdd, block, &bd_buf) call.
 >The same was in rtems_bdbuf_read but I fixed it in this
 >routine but forgot about rtems_bdbuf_get :(

 The attached patch fixes this issue.

 Also, releasing the disk was moved after re-enabling task preemption
 (for consistency; other routines in bdbuf.c also re-enable task
 preemption prior to releasing the disk)

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Ticket URL: <http://devel.rtems.org/ticket/1272#comment:2>
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