Re: kern/16284 running function in stoped gdb ...

[Nick Hudson <nick.hudson%gmx.co.uk@localhost>]

On Sunday 03 January 2010 21:10:06 David Laight wrote:
> The following reply was made to PR kern/16284; it has been noted by GNATS.
> 
> From: David Laight <david%l8s.co.uk@localhost>
> To: gnats-bugs%netbsd.org@localhost
> Cc:
> Subject: Re: kern/16284 running function in stoped gdb ...
> Date: Sun, 3 Jan 2010 21:07:54 +0000
> 
>  This still happens, errno is unchanged and the 'ret' value
>  from select() seems to be undefined.

It works for me on NetBSD/i386 netbsd-5 from around Dec 12th.

Where do you see the problem?

>  ktrace shows a 'RET syscall 0' for the return from select
>  errno is unchanged (unless set in the called function).
> 
>  gdb has to do some horrid stuff in order to call a process
>  function - and even the 'success' result is lost.
> 
>  Sometimes, but not always, I also see almost 2 seconds delay before
>  the output from the called function - not sure where that delay comes
>  from. (A 2nd ^C gives a "Corrupt Obj_Entry pointer in GOT" error.)
> 
>  Anyone know the ptrace interface well enough to know what gdb is
>  trying to do ?

set debug infrun 1

See below

> 
>       David
> 

Nick
-- 

kenny$ gdb bar                                                                  
                                                                          
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This GDB was configured as "i386--netbsdelf"...                                 
                                                                          
(gdb) set debug infrun 1                                                        
                                                                          
(gdb) run                                                                       
                                                                          
Starting program: /tmp/bar                                                      
                                                                          
infrun: wait_for_inferior                                                       
                                                                          
infrun: infwait_normal_state                                                    
                                                                          
infrun: TARGET_WAITKIND_STOPPED                                                 
                                                                          
infrun: stop_pc = 0xbbbf4770                                                    
                                                                          
infrun: quietly stopped                                                         
                                                                          
infrun: stop_stepping                                                           
                                                                          
infrun: resume (step=0, signal=0)                                               
                                                                          
infrun: wait_for_inferior                                                       
                                                                          
infrun: infwait_normal_state                                                    
                                                                          
infrun: TARGET_WAITKIND_STOPPED                                                 
                                                                          
infrun: stop_pc = 0xbbbf4770                                                    
                                                                          
infrun: quietly stopped                                                         
                                                                          
infrun: stop_stepping                                                           
                                                                          
infrun: proceed (addr=0xffffffff, signal=0, step=0)                             
                                                                          
infrun: resume (step=0, signal=0)                                               
                                                                          
infrun: wait_for_inferior                                                       
                                                                          
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0xbbbf4ab8
infrun: BPSTATE_WHAT_CHECK_SHLIBS
infrun: no stepping, continue
infrun: resume (step=1, signal=0)
infrun: prepare_to_wait
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0xbbbf5d72
infrun: trap expected
infrun: no stepping, continue
infrun: resume (step=0, signal=0)
infrun: prepare_to_wait
^Cinfrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0xbbb1ba87
infrun: random signal 2

Program received signal SIGINT, Interrupt.
infrun: stop_stepping
0xbbb1ba87 in select () from /usr/lib/libc.so.12
(gdb) p foo()
infrun: proceed (addr=0x804877c, signal=0, step=0)
infrun: resume (step=0, signal=0)
infrun: wait_for_inferior
hej
infrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0x8048540
infrun: BPSTATE_WHAT_STOP_SILENT
infrun: stop_stepping
$1 = void
(gdb) c
Continuing.
infrun: proceed (addr=0xffffffff, signal=144, step=0)
infrun: resume (step=0, signal=0)
infrun: wait_for_inferior
^Cinfrun: infwait_normal_state
infrun: TARGET_WAITKIND_STOPPED
infrun: stop_pc = 0xbbb1ba87
infrun: random signal 2

Program received signal SIGINT, Interrupt.
infrun: stop_stepping
0xbbb1ba87 in select () from /usr/lib/libc.so.12
(gdb)