Issue with kill after exec in testsuite

[Jeremy Drake]

On Fri, 11 Jul 2025, Jon Turney wrote:

> On 08/07/2025 20:02, Jeremy Drake via Cygwin-developers wrote:
> > I've run into an odd issue with exec and kill in winsup/testsuite that
> > doesn't happen in a more normal configuration.  What I'm doing is getting
>
> This is odd.
>
> Jst so I'm clear: This works when run normally, but but fails when run in the
> testsuite?

Correct.

> > the pid via getpid (), then forking.  In the forked child, I can call kill
> > (pid, SIGUSR1) without issue, but if instead I call execv (passing the
> > pid as an argument) and then call kill after the exec I get "No such
> > process" error.  Can anyone tell what I'm doing wrong?
> >
> > Here's the test output:
> > kill after exec: No such process
> > SUCCESS: The process with PID 3748 (child process of PID 5984) has been
> > terminated.
> > Timeout
> > FAIL winsup.api/killissue.exe (exit status: 124)
> >
> > And here's a test with the working fork/kill if 0'ed out and the broken
> > fork/exec/kill in place:
> > [...]
>
> Weird.
>
> The only think I can think of right now is if somehow the
> execv("/proc/self/exe") is escaping the testinst, and running against the
> (different) installed cygwin DLL instead?
>
> But that doesn't seem very plausible.

Yeah.  I wonder if this is related to the pgid of 0 I was seeing in the
testsuite also.  I'll see if I can get any more info out of a test.