Value being assigned to is no longer active.

Value being assigned to is no longer active.

[Shaun Jackman]

What does this error message mean?

(gdb) set $cpsr=0x1f
Value being assigned to is no longer active.
(gdb) set $pc=0x2000000
Value being assigned to is no longer active.
(gdb) show version
GNU gdb 6.3.50.20050419
...
This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-elf".

Thanks,
Shaun

Re: Value being assigned to is no longer active.

[Daniel Jacobowitz]

On Wed, Apr 20, 2005 at 04:58:24PM -0700, Shaun Jackman wrote:
> What does this error message mean?
> 
> (gdb) set $cpsr=0x1f
> Value being assigned to is no longer active.
> (gdb) set $pc=0x2000000
> Value being assigned to is no longer active.
> (gdb) show version
> GNU gdb 6.3.50.20050419
> ...
> This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-elf".

In this context, I'm not sure.  Could you show a whole session?

-- 
Daniel Jacobowitz
CodeSourcery, LLC

Re: Value being assigned to is no longer active.

[Shaun Jackman]

On 4/20/05, Daniel Jacobowitz <drow@false.org> wrote:
> On Wed, Apr 20, 2005 at 04:58:24PM -0700, Shaun Jackman wrote:
> > What does this error message mean?
> >
> > (gdb) set $cpsr=0x1f
> > Value being assigned to is no longer active.
> > (gdb) set $pc=0x2000000
> > Value being assigned to is no longer active.
> > (gdb) show version
> > GNU gdb 6.3.50.20050419
> > ...
> > This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-elf".
> 
> In this context, I'm not sure.  Could you show a whole session?

In the following snippet, the target hung after the "s", so I pressed Ctrl-c.

Cheers,
Shaun

(gdb) s
Program received signal SIGSTOP, Stopped (signal).
0x0000000c in ?? ()
(gdb) bt
#0  0x0000000c in ?? ()
(gdb) p/x $cpsr
$1 = 0x40000093
(gdb) set $cpsr=0x1f
Value being assigned to is no longer active.

Re: Value being assigned to is no longer active.

[Daniel Jacobowitz]

On Wed, Apr 20, 2005 at 08:16:37PM -0700, Shaun Jackman wrote:
> On 4/20/05, Daniel Jacobowitz <drow@false.org> wrote:
> > On Wed, Apr 20, 2005 at 04:58:24PM -0700, Shaun Jackman wrote:
> > > What does this error message mean?
> > >
> > > (gdb) set $cpsr=0x1f
> > > Value being assigned to is no longer active.
> > > (gdb) set $pc=0x2000000
> > > Value being assigned to is no longer active.
> > > (gdb) show version
> > > GNU gdb 6.3.50.20050419
> > > ...
> > > This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-elf".
> > 
> > In this context, I'm not sure.  Could you show a whole session?
> 
> In the following snippet, the target hung after the "s", so I pressed Ctrl-c.
> 
> Cheers,
> Shaun
> 
> (gdb) s
> Program received signal SIGSTOP, Stopped (signal).
> 0x0000000c in ?? ()
> (gdb) bt
> #0  0x0000000c in ?? ()
> (gdb) p/x $cpsr
> $1 = 0x40000093
> (gdb) set $cpsr=0x1f
> Value being assigned to is no longer active.

We'd need to be able to reproduce the problem.

I suspect that we've failed to create the first frame, somehow.

-- 
Daniel Jacobowitz
CodeSourcery, LLC

Re: Value being assigned to is no longer active.

[Shaun Jackman]

On 4/20/05, Daniel Jacobowitz <drow@false.org> wrote:
> We'd need to be able to reproduce the problem.
> 
> I suspect that we've failed to create the first frame, somehow.

I'm afraid I haven't found a simple set of events yet that recreates
this problem. Is there any other information I can provide? If not,
I'll try to find a set of steps that recreate the problem.

Cheers,
Shaun

Re: Value being assigned to is no longer active.

[Shaun Jackman]

On 4/20/05, Daniel Jacobowitz <drow@false.org> wrote:
> On Wed, Apr 20, 2005 at 04:58:24PM -0700, Shaun Jackman wrote:
> > What does this error message mean?
> >
> > (gdb) set $cpsr=0x1f
> > Value being assigned to is no longer active.
> > (gdb) set $pc=0x2000000
> > Value being assigned to is no longer active.
> > (gdb) show version
> > GNU gdb 6.3.50.20050419
> > ...
> > This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-elf".
> 
> In this context, I'm not sure.  Could you show a whole session?

Here's a complete session. I loaded and ran the program. It hung so I
interrupted it. I tried a backtrace, but the processor was in
no-man's-land, so I attempted to switch the chip back to user-mode to
see what its stack looked like.

Cheers,
Shaun

(gdb) target remote bdi:2001
Remote debugging using bdi:2001
0x01009810 in ?? ()
(gdb) lo
Loading section .text, size 0x2ece8 lma 0x2000000
Loading section .rodata, size 0x7e30 lma 0x202ece8
Loading section .data, size 0x19c8 lma 0x2036c18
Start address 0x2000000, load size 230624
Transfer rate: 108528 bits/sec, 312 bytes/write.
(gdb) c
Continuing.

Program received signal SIGSTOP, Stopped (signal).
0x00000010 in ?? ()
(gdb) bt
#0  0x00000010 in ?? ()
(gdb) p/x $cpsr
$1 = 0x20000097
(gdb) set $cpsr=0x1f
Value being assigned to is no longer active.
(gdb) p/x $cpsr=0x1f
Value being assigned to is no longer active.

Re: Value being assigned to is no longer active.

[Daniel Jacobowitz]

On Wed, Apr 27, 2005 at 09:36:03AM -0700, Shaun Jackman wrote:
> On 4/20/05, Daniel Jacobowitz <drow@false.org> wrote:
> > On Wed, Apr 20, 2005 at 04:58:24PM -0700, Shaun Jackman wrote:
> > > What does this error message mean?
> > >
> > > (gdb) set $cpsr=0x1f
> > > Value being assigned to is no longer active.
> > > (gdb) set $pc=0x2000000
> > > Value being assigned to is no longer active.
> > > (gdb) show version
> > > GNU gdb 6.3.50.20050419
> > > ...
> > > This GDB was configured as "--host=i686-pc-linux-gnu --target=arm-elf".
> > 
> > In this context, I'm not sure.  Could you show a whole session?
> 
> Here's a complete session. I loaded and ran the program. It hung so I
> interrupted it. I tried a backtrace, but the processor was in
> no-man's-land, so I attempted to switch the chip back to user-mode to
> see what its stack looked like.

OK, that's really bizarre.  I'm afraid I have no idea how this could
happen.

-- 
Daniel Jacobowitz
CodeSourcery, LLC

RE: Value being assigned to is no longer active.

[Decker, Paul]

Thanks, at least now I have some sort of starting point.

 

-----Original Message-----
From: Daniel Jacobowitz [mailto:drow@false.org] 
Sent: Tuesday, May 03, 2005 9:54 AM
To: Decker, Paul
Cc: gdb@sources.redhat.com
Subject: Re: Value being assigned to is no longer active.

On Tue, May 03, 2005 at 09:46:40AM -0400, Decker, Paul wrote:
> 
> 
> The "set debug remote 1" and "set debug frame 1" options seem to be 
> good things to know.

Yep.  Please fix your line wrapping; I've manually unwrapped this so
that I can read it.

> { create_sentinel_frame (...) -> {level=-1,type=<unknown> 
> type>,unwind=0x8227310,pc=<unknown>,id={!stack,!code,!special},func=<u
> nknown>} } { get_prev_frame_1 (this_frame=-1) -> 
> {level=0,type=<unknown>,unwind=<unknown>,pc=<unknown>,id=<unknown>,fun
> c=<unknown>} } { deprecated_update_frame_pc_hack 
> (frame=0,pc=0xffa00006) } { frame_register_unwind 
> (frame=-1,regnum=49(SP),...) -> *optimizedp=0 *lvalp=2 *addrp=0x8c 
> *bufferp=[f80fb0ff] } Sending packet: $mffa00002,c#1b...Ack Packet 
> received: 000000000000000000000000
> 0xffa00006 in ?? ()
> (gdb) p/x $PC
> { frame_register_unwind (frame=-1,regnum=0(PC),...) -> *optimizedp=0 
> *lvalp=2 *addrp=0x0 *bufferp=[0600a0ff] } { get_frame_id (fi=0) { 
> frame_register_unwind (frame=-1,regnum=51(FP),...) -> *optimizedp=0 
> *lvalp=2 *addrp=0x94 *bufferp=[dcb1bc48] } { frame_func_unwind (fi=-1)

> -> 0x0 }
> -> {!stack,!code,!special} }
> $1 = 0xffa00006
> (gdb) set $PC=0xFFA00000
> { frame_register_unwind (frame=-1,regnum=0(PC),...) -> *optimizedp=0 
> *lvalp=2 *addrp=0x0 *bufferp=[0600a0ff] } { frame_id_p 
> (l={!stack,!code,!special}) -> 0 } Value being assigned to is no
longer active.

The key here is that nothing claims the code at 0xffa00006 as any kind
of frame.  That means we end up with no frames at all except for the
special sentinal frame (at -1).

One solution would be to make sure that some frame sniffer for your
target does accept this frame.  Another would be to handle this in
common code by creating a special frame sniffer, at the end of the list,
which always accepts frame ID 0.  I'm not sure how practical that is
(haven't thought about it much).

--
Daniel Jacobowitz
CodeSourcery, LLC

Re: Value being assigned to is no longer active.

[Daniel Jacobowitz]

On Tue, May 03, 2005 at 09:46:40AM -0400, Decker, Paul wrote:
> 
> 
> The "set debug remote 1" and "set debug frame 1" options seem to be good
> things to know.  

Yep.  Please fix your line wrapping; I've manually unwrapped this so
that I can read it.

> { create_sentinel_frame (...) -> {level=-1,type=<unknown> type>,unwind=0x8227310,pc=<unknown>,id={!stack,!code,!special},func=<unknown>} }
> { get_prev_frame_1 (this_frame=-1) -> {level=0,type=<unknown>,unwind=<unknown>,pc=<unknown>,id=<unknown>,func=<unknown>} }
> { deprecated_update_frame_pc_hack (frame=0,pc=0xffa00006) }
> { frame_register_unwind (frame=-1,regnum=49(SP),...) -> *optimizedp=0 *lvalp=2 *addrp=0x8c *bufferp=[f80fb0ff] }
> Sending packet: $mffa00002,c#1b...Ack
> Packet received: 000000000000000000000000
> 0xffa00006 in ?? ()
> (gdb) p/x $PC
> { frame_register_unwind (frame=-1,regnum=0(PC),...) -> *optimizedp=0 *lvalp=2 *addrp=0x0 *bufferp=[0600a0ff] }
> { get_frame_id (fi=0) { frame_register_unwind (frame=-1,regnum=51(FP),...) -> *optimizedp=0 *lvalp=2 *addrp=0x94 *bufferp=[dcb1bc48] }
> { frame_func_unwind (fi=-1) -> 0x0 }
> -> {!stack,!code,!special} }
> $1 = 0xffa00006
> (gdb) set $PC=0xFFA00000
> { frame_register_unwind (frame=-1,regnum=0(PC),...) -> *optimizedp=0 *lvalp=2 *addrp=0x0 *bufferp=[0600a0ff] }
> { frame_id_p (l={!stack,!code,!special}) -> 0 }
> Value being assigned to is no longer active.

The key here is that nothing claims the code at 0xffa00006 as any kind
of frame.  That means we end up with no frames at all except for the
special sentinal frame (at -1).

One solution would be to make sure that some frame sniffer for your
target does accept this frame.  Another would be to handle this in
common code by creating a special frame sniffer, at the end of the
list, which always accepts frame ID 0.  I'm not sure how practical that
is (haven't thought about it much).

-- 
Daniel Jacobowitz
CodeSourcery, LLC

RE: Value being assigned to is no longer active.

[Decker, Paul]

The "set debug remote 1" and "set debug frame 1" options seem to be good
things to know.  


(gdb) set debug remote 1
(gdb) set debug frame 1
(gdb) target remote :1234
Remote debugging using :1234
Sending packet: $Hc-1#09...Ack
Packet received: OK
Sending packet: $qC#b4...Ack
Packet received:
Sending packet: $qOffsets#4b...Ack
Packet received:
Sending packet: $?#3f...Ack
Packet received: T00
{ flush_cached_frames () }
Sending packet: $Hg0#df...Ack
Packet received: OK
Sending packet: $p0#a0...Ack
Packet received:
Sending packet: $g#67...Ack
Packet received:
0600a0ff000008601400000104c8cbcfde367ffc01000000000000000dc8dd8
855017bb00000140004c8de36010000000dc8550108600001cbcf7ffc00000000dd887bb
0001404d
e01000d550810e0ff10e3fc8819f35d4ad837fc0a0400000022d02e983ab058a83ca8f09
00000000
00000000000000000000000000000000008b1eecfb4d23c56b1b6f89af80fb0ff9836bd4
8dcb1bc4
800000000000000000000000000000000000000000000002000000000010000000000800
34300010
000000000000044440bc001000000180100ef5a0000effeff7eff0600a0ff4463827e000
03044082
0000000ef08ef000030442000000000002000304400000013e0ff0404e0ff0003e0ff010
00000000
000000000a0ff0000000000000000
{ create_sentinel_frame (...) -> {level=-1,type=<unknown
type>,unwind=0x8227310,
pc=<unknown>,id={!stack,!code,!special},func=<unknown>} }
{ get_prev_frame_1 (this_frame=-1) ->
{level=0,type=<unknown>,unwind=<unknown>,p
c=<unknown>,id=<unknown>,func=<unknown>} }
{ deprecated_update_frame_pc_hack (frame=0,pc=0xffa00006) }
{ frame_register_unwind (frame=-1,regnum=49(SP),...) -> *optimizedp=0
*lvalp=2 *
addrp=0x8c *bufferp=[f80fb0ff] }
Sending packet: $mffa00002,c#1b...Ack
Packet received: 000000000000000000000000
0xffa00006 in ?? ()
(gdb) p/x $PC
{ frame_register_unwind (frame=-1,regnum=0(PC),...) -> *optimizedp=0
*lvalp=2 *a
ddrp=0x0 *bufferp=[0600a0ff] }
{ get_frame_id (fi=0) { frame_register_unwind
(frame=-1,regnum=51(FP),...) -> *o
ptimizedp=0 *lvalp=2 *addrp=0x94 *bufferp=[dcb1bc48] }
{ frame_func_unwind (fi=-1) -> 0x0 }
-> {!stack,!code,!special} }
$1 = 0xffa00006
(gdb) set $PC=0xFFA00000
{ frame_register_unwind (frame=-1,regnum=0(PC),...) -> *optimizedp=0
*lvalp=2 *a
ddrp=0x0 *bufferp=[0600a0ff] }
{ frame_id_p (l={!stack,!code,!special}) -> 0 }
Value being assigned to is no longer active.
(gdb) p/x $FP
{ frame_register_unwind (frame=-1,regnum=51(FP),...) -> *optimizedp=0
*lvalp=2 *
addrp=0x94 *bufferp=[dcb1bc48] }
$2 = 0x48bcb1dc
(gdb) set $FP=0x0
{ frame_register_unwind (frame=-1,regnum=51(FP),...) -> *optimizedp=0
*lvalp=2 *
addrp=0x94 *bufferp=[dcb1bc48] }
{ frame_id_p (l={!stack,!code,!special}) -> 0 }
Value being assigned to is no longer active.
(gdb) p/x $SP
{ frame_register_unwind (frame=-1,regnum=49(SP),...) -> *optimizedp=0
*lvalp=2 *
addrp=0x8c *bufferp=[f80fb0ff] }
$3 = 0xffb00ff8
(gdb) set $SP=0
{ frame_register_unwind (frame=-1,regnum=49(SP),...) -> *optimizedp=0
*lvalp=2 *
addrp=0x8c *bufferp=[f80fb0ff] }
{ frame_id_p (l={!stack,!code,!special}) -> 0 }
Value being assigned to is no longer active.
(gdb)






 

-----Original Message-----
From: gdb-owner@sources.redhat.com [mailto:gdb-owner@sources.redhat.com]
On Behalf Of Daniel Jacobowitz
Sent: Tuesday, May 03, 2005 9:41 AM
To: Decker, Paul
Cc: gdb@sources.redhat.com
Subject: Re: Value being assigned to is no longer active.

On Tue, May 03, 2005 at 09:38:18AM -0400, Decker, Paul wrote:
> Also, I've made my debug server print out the packets it sends and 
> receives, this is what is sent from the target to gdb.

You can get some similar information from gdb with "set debug remote".

Could you redo this with both "set debug remote 1" and "set debug frame
1" before you issue the "target remote" command?


--
Daniel Jacobowitz
CodeSourcery, LLC

Re: Value being assigned to is no longer active.

[Daniel Jacobowitz]

On Tue, May 03, 2005 at 09:38:18AM -0400, Decker, Paul wrote:
> Also, I've made my debug server print out the packets it sends and
> receives, this is what is sent from the target to gdb.

You can get some similar information from gdb with "set debug remote".

Could you redo this with both "set debug remote 1" and "set debug frame
1" before you issue the "target remote" command?


-- 
Daniel Jacobowitz
CodeSourcery, LLC

RE: Value being assigned to is no longer active.

[Decker, Paul]

I guess I lied a bit, I thought for sure I could set registers before
the load, but it seems I can not.


(gdb) target remote :1234
Remote debugging using :1234
0xffa00006 in ?? ()
(gdb) p/x $PC
$1 = 0xffa00006
(gdb) set $PC=0xFFA00000
Value being assigned to is no longer active.
(gdb) p/x $FP
$2 = 0x48bcb1dc
(gdb) p/x $R0
$3 = 0x0
(gdb) set $R0=3
Value being assigned to is no longer active.
(gdb) p/x $SP
$4 = 0xffb00ff8
(gdb) set $SP = 0
Value being assigned to is no longer active.
(gdb) set $FP=0
Value being assigned to is no longer active.
(gdb)

Also, I've made my debug server print out the packets it sends and
receives, this is what is sent from the target to gdb.

Selection>Connected on port: 56465
Remote debugging from host 127.0.0.1

Hc-1
Putpkt(OK)

qC
Putpkt()

qOffsets
Putpkt()

?
In the ???
Putpkt(T00)

Hg0
Putpkt(OK)

p0
Putpkt()

g
Putpkt(0600a0ff000000004400000104c8cbcfde367ffc01000000000000000dc8dd885
5017bb00
000440004c8de36010000000dc8550100000001cbcf7ffc00000000dd887bb0004404de0
1000d550
810e0ff10e3fc8819f35d4ad837fc0a0400000022d02e983ab058a83ca8f090000000000
00000000
0000000000000000000000008b1eecfb4d23c56b1b6f89af80fb0ff9836bd48dcb1bc480
00000000
000000000000000000000000000000000000020000000000100000000008003430001000
00000000
00044440bc001000000180100ef5a0000effeff7eff0600a0ff4463827e0000304408200
00000ef0
8ef000030442000000000002000304400000013e0ff0404e0ff0003e0ff0100000000000
0000000a
0ff0000000000000000)

mffa00002,c
Putpkt(000000000000000000000000)





 

-----Original Message-----
From: Daniel Jacobowitz [mailto:drow@false.org] 
Sent: Tuesday, May 03, 2005 9:21 AM
To: Decker, Paul
Cc: gdb@sources.redhat.com
Subject: Re: Value being assigned to is no longer active.

On Tue, May 03, 2005 at 09:00:51AM -0400, Decker, Paul wrote:
> 
> Hi Daniel,
> 
> I'll give u whatever I can, what is a transcript, and how do I produce

> it?

A log of the session showing the problem, from beginning to end.  You
can use the 'script' program, or copy/paste.


--
Daniel Jacobowitz
CodeSourcery, LLC

Re: Value being assigned to is no longer active.

[Daniel Jacobowitz]

On Tue, May 03, 2005 at 09:00:51AM -0400, Decker, Paul wrote:
> 
> Hi Daniel,
> 
> I'll give u whatever I can, what is a transcript, and how do I produce
> it?

A log of the session showing the problem, from beginning to end.  You
can use the 'script' program, or copy/paste.


-- 
Daniel Jacobowitz
CodeSourcery, LLC

RE: Value being assigned to is no longer active.

[Decker, Paul]

Hi Daniel,

I'll give u whatever I can, what is a transcript, and how do I produce
it?


Paul.

 

-----Original Message-----
From: Daniel Jacobowitz [mailto:drow@false.org] 
Sent: Tuesday, May 03, 2005 8:55 AM
To: Decker, Paul
Cc: gdb@sources.redhat.com
Subject: Re: Value being assigned to is no longer active.

On Tue, May 03, 2005 at 08:31:15AM -0400, Decker, Paul wrote:
>  
> 
> Being relatively new to using gdb, and developing a new target for it,

> I'm now getting this same error message.  I get it, after I have 
> loaded a program to my target.  Before performing a load, I can set 
> register values without any problems.  The load seems to work fine, 
> however at that point, I can not set any register values, including
the PC.
> 
> I would be grateful for any ideas, remember though, I'm very green 
> with gdb and the whole debug server stuff.

That's not enough information to reproduce... how about a transcript?


--
Daniel Jacobowitz
CodeSourcery, LLC

Re: Value being assigned to is no longer active.

[Daniel Jacobowitz]

On Tue, May 03, 2005 at 08:31:15AM -0400, Decker, Paul wrote:
>  
> 
> Being relatively new to using gdb, and developing a new target for it,
> I'm now getting this same error message.  I get it, after I have loaded
> a program to my target.  Before performing a load, I can set register
> values without any problems.  The load seems to work fine, however at
> that point, I can not set any register values, including the PC.
> 
> I would be grateful for any ideas, remember though, I'm very green with
> gdb and the whole debug server stuff.

That's not enough information to reproduce... how about a transcript?


-- 
Daniel Jacobowitz
CodeSourcery, LLC

Value being assigned to is no longer active.

[Decker, Paul]

 

Being relatively new to using gdb, and developing a new target for it,
I'm now getting this same error message.  I get it, after I have loaded
a program to my target.  Before performing a load, I can set register
values without any problems.  The load seems to work fine, however at
that point, I can not set any register values, including the PC.

I would be grateful for any ideas, remember though, I'm very green with
gdb and the whole debug server stuff.

thanks,
Paul.





-----Original Message-----
From: gdb-owner@sources.redhat.com [mailto:gdb-owner@sources.redhat.com]
On Behalf Of Daniel Jacobowitz
Sent: Wednesday, April 20, 2005 11:18 PM
To: Shaun Jackman
Cc: gdb@sources.redhat.com
Subject: Re: Value being assigned to is no longer active.

On Wed, Apr 20, 2005 at 08:16:37PM -0700, Shaun Jackman wrote:
> On 4/20/05, Daniel Jacobowitz <drow@false.org> wrote:
> > On Wed, Apr 20, 2005 at 04:58:24PM -0700, Shaun Jackman wrote:
> > > What does this error message mean?
> > >
> > > (gdb) set $cpsr=0x1f
> > > Value being assigned to is no longer active.
> > > (gdb) set $pc=0x2000000
> > > Value being assigned to is no longer active.
> > > (gdb) show version
> > > GNU gdb 6.3.50.20050419
> > > ...
> > > This GDB was configured as "--host=i686-pc-linux-gnu
--target=arm-elf".
> > 
> > In this context, I'm not sure.  Could you show a whole session?
> 
> In the following snippet, the target hung after the "s", so I pressed
Ctrl-c.
> 
> Cheers,
> Shaun
> 
> (gdb) s
> Program received signal SIGSTOP, Stopped (signal).
> 0x0000000c in ?? ()
> (gdb) bt
> #0  0x0000000c in ?? ()
> (gdb) p/x $cpsr
> $1 = 0x40000093
> (gdb) set $cpsr=0x1f
> Value being assigned to is no longer active.

We'd need to be able to reproduce the problem.

I suspect that we've failed to create the first frame, somehow.

--
Daniel Jacobowitz
CodeSourcery, LLC