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

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

The following reply was made to PR kern/16284; it has been noted by GNATS.

From: Nick Hudson <nick.hudson%gmx.co.uk@localhost>
To: gnats-bugs%netbsd.org@localhost,
 dsl%netbsd.org@localhost
Cc: kern-bug-people%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost,
 netbsd-bugs%netbsd.org@localhost,
 lha%stacken.kth.se@localhost
Subject: Re: kern/16284 running function in stoped gdb ...
Date: Mon, 4 Jan 2010 12:20:07 +0000

 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                                                                 
                                                                           
 GNU gdb 6.5                                                                    
                                                                           
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 There is absolutely no warranty for GDB.  Type "show warranty" for details.    
                                                                           
 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)