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Re: PID-reuse races fix, introduced GCC validation brakage
From: |
Pedro Alves |
Subject: |
Re: PID-reuse races fix, introduced GCC validation brakage |
Date: |
Thu, 31 Mar 2016 18:35:47 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.1 |
On 03/31/2016 04:25 PM, Yvan Roux wrote:
> Hi Pedro,
>
> On 31 March 2016 at 16:20, Pedro Alves <address@hidden> wrote:
> The regression is due to this part:
>
> + # Reap it.
> + set res [catch "wait -i $program_id" wres]
> + if {$exec_pid != -1} {
> + # We reaped the process, so cancel the pending force-kills, as
> + # otherwise if the PID is reused for some other unrelated
> + # process, we'd kill the wrong process.
> + exec sh -c "exec > /dev/null 2>&1 && kill -9 $exec_pid"
> + }
>
> In our case the "wait -i" command ends without any effect on the
> running processes
"wait" just reaps an already zombie process. So if that returns,
$program_id either already exited and is zombie, or wait
returned an error.
> and then it kills the command which was about to
> kill them, and the validation is stuck.
>
So before my patch, the "wait -i" would also return immediately,
but it just happened that the "kill -15 $pgid" etc. commands kept
running in the background and ended up killing the processes
after the 5 / 10 seconds sleeps. Correct?
How come the "wait -i" returns before _any_ process is
dead/zombie, as you say? Did wait return an error?
I suspect that's something to do with taking the open path
instead of spawn, due to redirection.
And I wonder why the "kill -2 $pgid | kill -2 $pid" command didn't
cause "cat" to exit?
Thanks,
Pedro Alves
- PID-reuse races fix, introduced GCC validation brakage, Yvan Roux, 2016/03/30
- Re: PID-reuse races fix, introduced GCC validation brakage, Christophe Lyon, 2016/03/30
- Re: PID-reuse races fix, introduced GCC validation brakage, Yvan Roux, 2016/03/30
- Re: PID-reuse races fix, introduced GCC validation brakage, Christophe Lyon, 2016/03/30
- Re: PID-reuse races fix, introduced GCC validation brakage, Yvan Roux, 2016/03/30
- Re: PID-reuse races fix, introduced GCC validation brakage, Ben Elliston, 2016/03/30
- Re: PID-reuse races fix, introduced GCC validation brakage, Yvan Roux, 2016/03/30
Re: PID-reuse races fix, introduced GCC validation brakage, Pedro Alves, 2016/03/31
- Re: PID-reuse races fix, introduced GCC validation brakage, Yvan Roux, 2016/03/31
- Re: PID-reuse races fix, introduced GCC validation brakage,
Pedro Alves <=
- Re: PID-reuse races fix, introduced GCC validation brakage, Yvan Roux, 2016/03/31
- Re: PID-reuse races fix, introduced GCC validation brakage, Pedro Alves, 2016/03/31
- Re: PID-reuse races fix, introduced GCC validation brakage, Yvan Roux, 2016/03/31
- Re: PID-reuse races fix, introduced GCC validation brakage, Pedro Alves, 2016/03/31
- Re: PID-reuse races fix, introduced GCC validation brakage, Yvan Roux, 2016/03/31
- Re: PID-reuse races fix, introduced GCC validation brakage, Pedro Alves, 2016/03/31
Re: PID-reuse races fix, introduced GCC validation brakage, Pedro Alves, 2016/03/31