Re: Bug in i386_process_record?

[Hui Zhu <teawater at gmail dot com>]

Thanks Michael.

Could you send "memrange-reverse.c" to me?

It looks like I handler rep not very well.

Hui

On Fri, Aug 7, 2009 at 11:39, Michael Snyder<msnyder@vmware.com> wrote:
> Hi Hui,
>
> While experimenting with your dump/load commands, I think I discovered
> a bug in i386_process_record, in the handling of the "string ops"
> and the "rep" prefix. ?Looks like we are saving the same data over
> and over in the log.
>
> This was made using the attached sample program.
>
> ?(gdb) break main
> ? ?Breakpoint 1 at 0x80483c4: file memrange-reverse.c, line 29.
> ?(gdb) run
> ? ?Starting program:
> ? ?Breakpoint 1, main ()
> ? ?29 ? ? ? ?memset (blob1, 'a', sizeof (blob1));
> ?(gdb) record
> ?(gdb) next
> ? ?30 ? ? ? ?blob1[sizeof (blob1) - 1] = '\0';
> ?(gdb) record dump
> ? ?Saving recording to file 'rec.27255'
> ? ?Writing 4-byte magic cookie RECORD_FILE_MAGIC (0x26070920)
> ?[...]
> ?Writing register 7 val 0x0000000008049684 (1 plus 8 plus 16 bytes)
> ?Writing memory 0x08049680 (1 plus 8 plus 8 bytes plus 1024 bytes)
> ?Writing register 1 val 0x00000000000000ff (1 plus 8 plus 16 bytes)
> ?Writing register 8 val 0x0000000000587be7 (1 plus 8 plus 16 bytes)
> ?Writing record_end (1 byte)
> ?Writing register 7 val 0x0000000008049688 (1 plus 8 plus 16 bytes)
> ?Writing memory 0x08049684 (1 plus 8 plus 8 bytes plus 1020 bytes)
> ?Writing register 1 val 0x00000000000000fe (1 plus 8 plus 16 bytes)
> ?Writing register 8 val 0x0000000000587be7 (1 plus 8 plus 16 bytes)
> ?Writing record_end (1 byte)
> ?Writing register 7 val 0x000000000804968c (1 plus 8 plus 16 bytes)
> ?Writing memory 0x08049688 (1 plus 8 plus 8 bytes plus 1016 bytes)
> ?Writing register 1 val 0x00000000000000fd (1 plus 8 plus 16 bytes)
> ?Writing register 8 val 0x0000000000587be7 (1 plus 8 plus 16 bytes)
> ?Writing record_end (1 byte)
> ?Writing register 7 val 0x0000000008049690 (1 plus 8 plus 16 bytes)
> ?Writing memory 0x0804968c (1 plus 8 plus 8 bytes plus 1012 bytes)
> ?Writing register 1 val 0x00000000000000fc (1 plus 8 plus 16 bytes)
> ?Writing register 8 val 0x0000000000587be7 (1 plus 8 plus 16 bytes)
> ?Writing record_end (1 byte)
> ?Writing register 7 val 0x0000000008049694 (1 plus 8 plus 16 bytes)
> ?Writing memory 0x08049690 (1 plus 8 plus 8 bytes plus 1008 bytes)
> ?Writing register 1 val 0x00000000000000fb (1 plus 8 plus 16 bytes)
> ?Writing register 8 val 0x0000000000587be7 (1 plus 8 plus 16 bytes)
> ?Writing record_end (1 byte)
> ?Writing register 7 val 0x0000000008049698 (1 plus 8 plus 16 bytes)
> ?Writing memory 0x08049694 (1 plus 8 plus 8 bytes plus 1004 bytes)
> ?Writing register 1 val 0x00000000000000fa (1 plus 8 plus 16 bytes)
> ?Writing register 8 val 0x0000000000587be7 (1 plus 8 plus 16 bytes)
> ?Writing record_end (1 byte)
> ?Writing register 7 val 0x000000000804969c (1 plus 8 plus 16 bytes)
> ?Writing memory 0x08049698 (1 plus 8 plus 8 bytes plus 1000 bytes)
> ?Writing register 1 val 0x00000000000000f9 (1 plus 8 plus 16 bytes)
> ?Writing register 8 val 0x0000000000587be7 (1 plus 8 plus 16 bytes)
> ?Writing record_end (1 byte)
> ?Writing register 7 val 0x00000000080496a0 (1 plus 8 plus 16 bytes)
> ?Writing memory 0x0804969c (1 plus 8 plus 8 bytes plus 996 bytes)
> ?Writing register 1 val 0x00000000000000f8 (1 plus 8 plus 16 bytes)
> ?Writing register 8 val 0x0000000000587be7 (1 plus 8 plus 16 bytes)
> ?[...]
>
> Altogether there were 256 duplicate entries, each one is
> four bytes shorter than the previous one.
>
>