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From: Oleg Nesterov <oleg@redhat.com>
To: Rik van Riel <riel@surriel.com>
Cc: Gargi Sharma <gs051095@gmail.com>,
	linux-kernel@vger.kernel.org, julia.lawall@lip6.fr,
	akpm@linux-foundation.org, mingo@kernel.org,
	pasha.tatashin@oracle.com, ktkhai@virtuozzo.com
Subject: Re: [PATCH v2 1/2] pid: Replace pid bitmap implementation with IDR API
Date: Wed, 27 Sep 2017 16:06:58 +0200	[thread overview]
Message-ID: <20170927140658.GA28133@redhat.com> (raw)
In-Reply-To: <1506517794.21121.93.camel@surriel.com>

On 09/27, Rik van Riel wrote:
>
> > @@ -240,17 +230,18 @@ void zap_pid_ns_processes(struct pid_namespace
> > *pid_ns)
> >  	 *
> >  	 */
> >  	read_lock(&tasklist_lock);
> > -	nr = next_pidmap(pid_ns, 1);
> > -	while (nr > 0) {
> > -		rcu_read_lock();
> > +	pid = idr_get_next(&pid_ns->idr, &nr);
> > +	while (pid) {
> >  
> > -		task = pid_task(find_vpid(nr), PIDTYPE_PID);
> > -		if (task && !__fatal_signal_pending(task))
> > -			send_sig_info(SIGKILL, SEND_SIG_FORCED,
> > task);
> > +		rcu_read_lock();
> >  
> > +		idr_for_each_entry_continue(&pid_ns->idr, pid, nr) {
> > +			task = pid_task(pid, PIDTYPE_PID);
> > +			if (task && !__fatal_signal_pending(task))
> > +				send_sig_info(SIGKILL,
> > SEND_SIG_FORCED, task);
> > +		}
> >  		rcu_read_unlock();
> >  
> > -		nr = next_pidmap(pid_ns, nr);
> >  	}
> >  	read_unlock(&tasklist_lock);
> >  
> 
> I believe we should be fine with just the idr_for_each_entry_continue()
> surrounding the loop,

Yes, and please move "nr = 2" close to idr_for_each_entry_continue() to
make it clear why do we use _continue (to skip nr == 1).

> and not need the while (pid) around that.
>
> That should still iterate over all the pids in the namespace, and
> simplify the code even more.

And make this patch correct ;)

because currently it is wrong, zap_pid_ns_processes() won't kill the pid
returned by the first idr_get_next().

Oleg.

  reply	other threads:[~2017-09-27 14:07 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-27  5:06 [PATCH v2 0/2] Replace PID bitmap allocation with IDR API Gargi Sharma
2017-09-27  5:06 ` [PATCH v2 1/2] pid: Replace pid bitmap implementation " Gargi Sharma
2017-09-27 13:09   ` Rik van Riel
2017-09-27 14:06     ` Oleg Nesterov [this message]
2017-09-27 15:06       ` Gargi Sharma
2017-09-27 15:15         ` Oleg Nesterov
2017-09-27 15:05     ` Gargi Sharma
2017-09-27 15:05   ` Oleg Nesterov
2017-10-01  9:15   ` Christoph Hellwig
2017-10-01 10:35     ` Gargi Sharma
2017-10-02 13:14       ` Rik van Riel
2017-10-02 13:05     ` Rik van Riel
2017-09-27  5:06 ` [PATCH v2 2/2] pid: Remove pidhash Gargi Sharma
2017-09-27 15:45   ` Oleg Nesterov
2017-09-27 16:28     ` Oleg Nesterov
2017-09-30 15:41       ` Gargi Sharma
2017-10-02 15:03         ` Oleg Nesterov
2017-10-02 13:35     ` Rik van Riel
2017-10-02 13:45       ` Rik van Riel
2017-10-02 15:21       ` Oleg Nesterov
2017-10-02 15:22         ` Rik van Riel
2017-10-02 16:27           ` Gargi Sharma
2017-09-27 17:18 ` [PATCH v2 0/2] Replace PID bitmap allocation with IDR API Eric W. Biederman
     [not found]   ` <CAOCi2DESqWV2YPcRTe6NYjx6m6N19ewXbAyfLfeBa23kJiEO9Q@mail.gmail.com>
2017-09-28 19:46     ` Rik van Riel
2017-09-28 20:05       ` Gargi Sharma
2017-09-29  0:35         ` Rik van Riel

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