[lldb-dev] Resuming traced process on Linux and SIGSTOP

[Todd Fiala]

Hey Andrew, this looks fine.  It also tested out just fine as well.


On Tue, Mar 25, 2014 at 12:11 PM, Todd Fiala <tfiala at google.com> wrote:

> Sure thing :-)
>
>
> On Tue, Mar 25, 2014 at 12:10 PM, Andrew MacPherson <andrew.macp at gmail.com
> > wrote:
>
>> Great, thanks Todd!
>>
>>
>> On Tue, Mar 25, 2014 at 8:09 PM, Todd Fiala <tfiala at google.com> wrote:
>>
>>> I just finished clearing out some Linux test errors (I'm now all green
>>> on Linux x86_64).  I'll add this to a queue I've got with some changes from
>>> Piotr, Ed and you in it now.
>>>
>>>
>>> On Tue, Mar 25, 2014 at 12:08 PM, Andrew MacPherson <
>>> andrew.macp at gmail.com> wrote:
>>>
>>>> Just pinging this again in case anyone has a chance to review the small
>>>> Linux detach patch here. Thanks!
>>>>
>>>>
>>>> On Sat, Mar 22, 2014 at 11:05 AM, Andrew MacPherson <
>>>> andrew.macp at gmail.com> wrote:
>>>>
>>>>> I'm attaching a patch here that resolves the issue of a signal being
>>>>> delivered to the inferior on detach, let me know if I should start a new
>>>>> thread for this but since it's related to what we were discussing I'm
>>>>> attaching it here. To reproduce the issue just launch a process, then in a
>>>>> new terminal:
>>>>>
>>>>> sudo lldb -p <pid>
>>>>> c
>>>>> q
>>>>>
>>>>> When quitting the inferior receives a SIGSTOP because the process is
>>>>> already running when the PTRACE_DETACH is sent. I can't find a clear answer
>>>>> on what's supposed to happen here (PTRACE_DETACH sent to running thread)
>>>>> but this is the behaviour I'm seeing. The docs do indicate that
>>>>> PRACE_DETACH is like PTRACE_CONT and should only be sent to a stopped
>>>>> thread.
>>>>>
>>>>> I also tried to add a unit test for this and the previous patch,
>>>>> however I hit http://llvm.org/pr16172. The tests these two patches
>>>>> require are similar to the one mentioned in that case and I get the same
>>>>> errors in my sample test as when running that one:
>>>>>
>>>>> attach -p <pid> (ok)
>>>>> c (ok)
>>>>> detach (error: Detach failed: No such process)
>>>>>
>>>>> And:
>>>>>
>>>>> attach -p <pid> (ok)
>>>>> c (ok)
>>>>> process interrupt (ok)
>>>>> c (error: Failed to resume process: Resume request failed - process
>>>>> still running..)
>>>>>
>>>>>
>>>>> On Fri, Mar 21, 2014 at 8:37 PM, Ed Maste <emaste at freebsd.org> wrote:
>>>>>
>>>>>> On 21 March 2014 15:14,  <jingham at apple.com> wrote:
>>>>>> > I'm pretty sure we have some test cases that test attach.  If we
>>>>>> don't, then it would be great to add one.  If we do, then it would be
>>>>>> interesting to see why they didn't fail.  For instance, maybe they just
>>>>>> didn't bother to try "continue" after the attach.  Just adding that would
>>>>>> be good too.
>>>>>>
>>>>>> We definitely have some, because they used to fail early on in the
>>>>>> FreeBSD porting effort.  I suspect that your suggestion is correct and
>>>>>> they just don't do anything but attach and then quit.
>>>>>>
>>>>>> On a related note, I'm pretty sure we don't have tests for detach.
>>>>>> I'll see about extending tests to include that at some point.
>>>>>>
>>>>>> -Ed
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>> --
>>>  Todd Fiala | Software Engineer |  tfiala at google.com |  650-943-3180
>>>
>>
>>
>
>
> --
> Todd Fiala | Software Engineer |  tfiala at google.com |  650-943-3180
>



-- 
Todd Fiala | Software Engineer | tfiala at google.com | 650-943-3180
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