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* what is the function of EXCEPTIONS_SIGLONGJMP?
@ 2012-09-13  9:55 John Smith
  2012-09-15  6:08 ` Jan Kratochvil
  0 siblings, 1 reply; 4+ messages in thread
From: John Smith @ 2012-09-13  9:55 UTC (permalink / raw)
  To: gdb

hi:
   when I  debug gdb using gdb self ,  after I  type "start" command ,
 the prompt  is  as  below :
       Warning:
      Cannot insert breakpoint 0.
      Error accessing memory address 0xdb6a5194: /.
      0xb7589571 in siglongjmp () from /lib/i686/cmov/libc.so.6

 it seem to be some exceptions  happened  when  dealing with  break points  .

 and Is there some  interpret  here ?


thanks!

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: what is the function of EXCEPTIONS_SIGLONGJMP?
  2012-09-13  9:55 what is the function of EXCEPTIONS_SIGLONGJMP? John Smith
@ 2012-09-15  6:08 ` Jan Kratochvil
  2012-09-16  6:50   ` John Smith
  0 siblings, 1 reply; 4+ messages in thread
From: Jan Kratochvil @ 2012-09-15  6:08 UTC (permalink / raw)
  To: John Smith; +Cc: gdb

On Thu, 13 Sep 2012 11:55:34 +0200, John Smith wrote:
>    when I  debug gdb using gdb self ,  after I  type "start" command ,
>  the prompt  is  as  below :
>        Warning:
>       Cannot insert breakpoint 0.
>       Error accessing memory address 0xdb6a5194: /.
>       0xb7589571 in siglongjmp () from /lib/i686/cmov/libc.so.6
> 
>  it seem to be some exceptions  happened  when  dealing with  break points  .

You are trying to step over longjmp or siglongjmp call.  This is supported
only with SystemTap-extended glibc, this is implemented only in recent glibc
and recent GDB.  Recent Fedora releases also have it working.
glibc/
	commit 8422c9a560e6e3c854739c8a13ecb1c6714f930f
	Author: Roland McGrath <roland@hack.frob.com>
	Date:   Fri May 25 13:31:57 2012 -0700
	    Add systemtap static probe points in setjmp/longjmp on x86.
gdb/
	commit 014135139c612fe1fbe6f11d2350f72325a66f7c
	Author: sergiodj <sergiodj>
	Date:   Fri Apr 27 20:48:52 2012 +0000
	    2012-04-27  Sergio Durigan Junior  <sergiodj@redhat.com>
			Tom Tromey  <tromey@redhat.com>

I just do not understand how that can happen during 'start' command, 'start'
is just doing 'tbreak' and 'run', there is no stepping involved anywhere.


Regards,
Jan

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: what is the function of EXCEPTIONS_SIGLONGJMP?
  2012-09-15  6:08 ` Jan Kratochvil
@ 2012-09-16  6:50   ` John Smith
  2012-09-16  7:15     ` Jan Kratochvil
  0 siblings, 1 reply; 4+ messages in thread
From: John Smith @ 2012-09-16  6:50 UTC (permalink / raw)
  To: gdb

  I  am not trying to  step over longjump, I just  trace the event loop
>  procedure of gdb
> so why does  that exception occured?

2012/9/15 Jan Kratochvil <jan.kratochvil@redhat.com>:
> On Thu, 13 Sep 2012 11:55:34 +0200, John Smith wrote:
>>    when I  debug gdb using gdb self ,  after I  type "start" command ,
>>  the prompt  is  as  below :
>>        Warning:
>>       Cannot insert breakpoint 0.
>>       Error accessing memory address 0xdb6a5194: /.
>>       0xb7589571 in siglongjmp () from /lib/i686/cmov/libc.so.6
>>
>>  it seem to be some exceptions  happened  when  dealing with  break points  .
>
> You are trying to step over longjmp or siglongjmp call.  This is supported
> only with SystemTap-extended glibc, this is implemented only in recent glibc
> and recent GDB.  Recent Fedora releases also have it working.
> glibc/
>         commit 8422c9a560e6e3c854739c8a13ecb1c6714f930f
>         Author: Roland McGrath <roland@hack.frob.com>
>         Date:   Fri May 25 13:31:57 2012 -0700
>             Add systemtap static probe points in setjmp/longjmp on x86.
> gdb/
>         commit 014135139c612fe1fbe6f11d2350f72325a66f7c
>         Author: sergiodj <sergiodj>
>         Date:   Fri Apr 27 20:48:52 2012 +0000
>             2012-04-27  Sergio Durigan Junior  <sergiodj@redhat.com>
>                         Tom Tromey  <tromey@redhat.com>
>
> I just do not understand how that can happen during 'start' command, 'start'
> is just doing 'tbreak' and 'run', there is no stepping involved anywhere.
>
>
> Regards,
> Jan

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: what is the function of EXCEPTIONS_SIGLONGJMP?
  2012-09-16  6:50   ` John Smith
@ 2012-09-16  7:15     ` Jan Kratochvil
  0 siblings, 0 replies; 4+ messages in thread
From: Jan Kratochvil @ 2012-09-16  7:15 UTC (permalink / raw)
  To: John Smith; +Cc: gdb

On Sun, 16 Sep 2012 08:50:08 +0200, John Smith wrote:
>   I  am not trying to  step over longjump, I just  trace the event loop
> >  procedure of gdb
> > so why does  that exception occured?

"trace the event loop" is too ambiguous, you should copy-paste your session.

Various features of GDB enable stepping mode which will then fail with old
system components like you described.


Regards,
Jan

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-09-16  7:15 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-09-13  9:55 what is the function of EXCEPTIONS_SIGLONGJMP? John Smith
2012-09-15  6:08 ` Jan Kratochvil
2012-09-16  6:50   ` John Smith
2012-09-16  7:15     ` Jan Kratochvil

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