Re: Seems like a bug in target_read_stack / dcache_xfer_memory?

Hui Zhu
2009-10-26T08:25:48Z

Thanks Doug.

Hui

On Sat, Oct 24, 2009 at 01:18, Doug Evans <dje@google.com> wrote:
>  On Thu, Oct 22, 2009 at 12:54 PM, Michael Snyder <msnyder@vmware.com> wrote:
>> Michael Snyder wrote:
>>>
>>> Doug Evans wrote:
>>>>
>>>> On Mon, Oct 19, 2009 at 2:35 PM, Michael Snyder <msnyder@vmware.com>
>>>> wrote:
>>>>>
>>>>> Anyway, yes, that's what it does.  dcache returns zero,
>>>>> and memory_xfer_partial bails out instead of trying the
>>>>> next target down the target stack.
>>>>
>>>> Hi.  If it will help I'll play with your testcase tomorrow.
>>>> I'll also volunteer to make a pass through the code and add some
>>>> comments.
>>>> [I mention that just in case you or someone is already in the process
>>>> of doing that.]
>>>
>>> Sure it will help.  Thanks, Doug.
>>
>> And the test case is in the repo now -- solib-precsave.exp.
>> How to run tests:
>> http://www.sourceware.org/gdb/wiki/ProcessRecord#head-2f56f7474cf60c6a5879ba6d8a4e4d034e6d0c8e
>
> Thanks for the testcase.
> You may be right about needing to test for "res == 0" but I'm less
> sure now, so I'm going to leave it as is, at least for now.
> dcache calls target_read (TARGET_OBJECT_RAW_MEMORY) which should DTRT.
> And in fact it does with this patch. :-)
> Checked in.
>
> 2009-10-23  Doug Evans  <dje@google.com>
>
>        * record.c (record_core_xfer_partial): Pass correct offset to
>        record_beneath_to_xfer_partial.
>
> Index: record.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/record.c,v
> retrieving revision 1.33
> diff -u -p -r1.33 record.c
> --- record.c    23 Oct 2009 16:11:37 -0000      1.33
> +++ record.c    23 Oct 2009 17:07:08 -0000
> @@ -1629,6 +1629,7 @@ record_core_xfer_partial (struct target_
>                if (offset >= p->addr)
>                  {
>                    struct record_core_buf_entry *entry;
> +                  ULONGEST sec_offset;
>
>                    if (offset >= p->endaddr)
>                      continue;
> @@ -1636,7 +1637,7 @@ record_core_xfer_partial (struct target_
>                    if (offset + len > p->endaddr)
>                      len = p->endaddr - offset;
>
> -                   offset -= p->addr;
> +                   sec_offset = offset - p->addr;
>
>                    /* Read readbuf or write writebuf p, offset, len.  */
>                    /* Check flags.  */
> @@ -1673,7 +1674,8 @@ record_core_xfer_partial (struct target_
>                            record_core_buf_list = entry;
>                          }
>
> -                        memcpy (entry->buf + offset, writebuf, (size_t) len);
> +                        memcpy (entry->buf + sec_offset, writebuf,
> +                               (size_t) len);
>                      }
>                    else
>                      {
> @@ -1683,7 +1685,8 @@ record_core_xfer_partial (struct target_
>                                    object, annex, readbuf, writebuf,
>                                    offset, len);
>
> -                       memcpy (readbuf, entry->buf + offset, (size_t) len);
> +                       memcpy (readbuf, entry->buf + sec_offset,
> +                              (size_t) len);
>                      }
>
>                    return len;
>