Re: [PATCH 1/3] Make remote follow fork 'Detaching' message match native

[Pedro Alves <palves at redhat dot com>]

On 05/22/2015 07:55 PM, Don Breazeal wrote:
> This patch fixes a couple of failures in gdb.base/foll-vfork.exp for
> extended-remote targets.  The failures were the result of the
> verbose/debug "Detaching..." messages in infrun.c:follow_fork_inferior
> not matching what was expected in the extended-remote case.
> 
> The path modifies the ptids used in the messages to ensure that they
> print "process nnn" instead of (possibly) "Thread nnn.nnn".  

...

> The
> ptids for the native case are already in this form, so there the
> change has no effect.  

This isn't true.  What happens is that linux_nat_pid_to_str
gives (pid,pid,0) special treatment:

(top-gdb) p ptid
$2 = {pid = 14246, lwp = 14246, tid = 0}
(top-gdb) bt
#0  linux_nat_pid_to_str (ops=0xe357f0, ptid=...) at /home/pedro/gdb/mygit/src/gdb/linux-nat.c:4078
#1  0x0000000000675bb5 in delegate_pid_to_str (self=0xe357f0, arg1=...) at /home/pedro/gdb/mygit/src/gdb/target-delegates.c:1438
#2  0x0000000000682641 in target_pid_to_str (ptid=...) at /home/pedro/gdb/mygit/src/gdb/target.c:2212
#3  0x00000000006245b2 in follow_fork_inferior (follow_child=0, detach_fork=1) at /home/pedro/gdb/mygit/src/gdb/infrun.c:449
#4  0x0000000000624e7e in follow_fork () at /home/pedro/gdb/mygit/src/gdb/infrun.c:722
#5  0x000000000062a531 in handle_inferior_event_1 (ecs=0x7fffffffd180) at /home/pedro/gdb/mygit/src/gdb/infrun.c:4072

> The ptids in the extended-remote case must be
> reported by gdbserver in the (pid,pid,0) form in order to later
> identify and remove new fork children that are reported prematurely
> by remote_update_thread_list.  

(so this bit is actually irrelevant)

> So here we generate process-style ptids
> to get identical messages in both native and extended-remote cases.
> 
> OK?

Still, detach is a process-wide operation, so this makes
sense anyway.

OK with commit log fixed.

Thanks,
Pedro Alves