qL and qf remote packets [Re: [Kgdb-bugreport] Re: [discuss] kgdb-x86_64-1.6 for kernel 2.4.23]

[George Anzinger]

Andrew Cagney wrote:
>> On Tue, Dec 30, 2003 at 06:11:29PM +0530, Amit S. Kale wrote:
>>
>>> While q[s/f] packet itself doesn't have pid wrap-around problem, I 
>>> can't figure out what will happen to gdb's database of threads in 
>>> following scenario.
>>>
>>> 1. GDB adds a thread with id 1500 to thread database.
>>> 2. It finds that the thread has died later.
>>> 3. Does it delete the thread from its database?
>>> 4. It again finds a thread with id 1500 becase of wrapping around of 
>>> pid. If it has completely forgotten about previous thread in its 
>>> dabase, there shouldn't be any problem.
>>
>>
>>
>> Indeed, there won't be any problem.  I believe that even if thread 1500
>> exists, and then dies and restarts between breakpoints, GDB still won't
>> get confused.
> 
> 
> The user might (eventually).  They aren't going to be notified of thread 
> create/delete events.  Also, it could leave around per-thread 
> breakpoings no longer applicable to that thread.

I think this might be more of a problem in user land.  In the kernel, first it 
is rare to reuse a pid, but still, if it is reused, it is expected.  To help the 
user we also use the thread info command to insert the tasks name in the info 
thread command.


-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml