From: Frederic Weisbecker <frederic@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@kernel.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: [patch 6/6] posix-cpu-timers: Make PID=0 and PID=self handling consistent
Date: Mon, 23 Sep 2019 16:13:25 +0200 [thread overview]
Message-ID: <20190923141324.GB10778@lenoir> (raw)
In-Reply-To: <20190905120540.162032542@linutronix.de>
On Thu, Sep 05, 2019 at 02:03:45PM +0200, Thomas Gleixner wrote:
> If the PID encoded into the clock id is 0 then the target is either the
> calling thread itself or the process to which it belongs.
>
> If the current thread encodes its own PID on a process wide clock then
> there is no reason not to treat it in the same way as the PID=0 case.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> kernel/time/posix-cpu-timers.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> --- a/kernel/time/posix-cpu-timers.c
> +++ b/kernel/time/posix-cpu-timers.c
> @@ -90,7 +90,14 @@ static struct task_struct *lookup_task(c
>
> } else {
> /*
> - * For processes require that p is group leader.
> + * Timer is going to be attached to a process. If p is
> + * current then treat it like the PID=0 case above.
> + */
> + if (p == current)
> + return current->group_leader;
> +
> + /*
> + * For foreign processes require that p is group leader.
> */
> if (!has_group_leader_pid(p))
> return NULL;
So, right after you should have that:
if (same_thread_group(p, current))
return p;
Which I suggested to convert as:
if (p == current)
return p;
Either way, you can now remove those lines.
And then:
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
next prev parent reply other threads:[~2019-09-23 14:13 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 12:03 [patch 0/6] posix-cpu-timers: Fallout fixes and permission tightening Thomas Gleixner
2019-09-05 12:03 ` [patch 1/6] posix-cpu-timers: Always clear head pointer on dequeue Thomas Gleixner
2019-09-05 15:49 ` Frederic Weisbecker
2019-09-05 12:03 ` [patch 2/6] posix-cpu-timers: Fix permission check regression Thomas Gleixner
2019-09-05 17:31 ` Frederic Weisbecker
2019-09-05 18:55 ` Thomas Gleixner
2019-09-05 21:15 ` [patch V2 " Thomas Gleixner
2019-09-09 15:13 ` Frederic Weisbecker
2019-09-10 11:18 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-09-05 12:03 ` [patch 3/6] posix-cpu-timers: Restrict timer_create() permissions Thomas Gleixner
2019-09-21 0:44 ` Frederic Weisbecker
2019-09-05 12:03 ` [patch 4/6] posix-cpu-timers: Restrict clock_gettime() permissions Thomas Gleixner
2019-09-23 13:39 ` Frederic Weisbecker
2019-09-05 12:03 ` [patch 5/6] posix-cpu-timers: Sanitize thread clock permissions Thomas Gleixner
2019-09-05 12:21 ` Peter Zijlstra
2019-09-05 14:11 ` Thomas Gleixner
2019-09-23 14:03 ` Frederic Weisbecker
2019-09-05 12:03 ` [patch 6/6] posix-cpu-timers: Make PID=0 and PID=self handling consistent Thomas Gleixner
2019-09-23 14:13 ` Frederic Weisbecker [this message]
2019-09-23 14:17 ` Thomas Gleixner
2019-09-05 14:48 ` [patch 0/6] posix-cpu-timers: Fallout fixes and permission tightening Frederic Weisbecker
2019-09-05 14:57 ` Thomas Gleixner
2019-09-05 15:21 ` Frederic Weisbecker
2019-09-05 20:32 ` Kees Cook
2019-09-05 21:13 ` Thomas Gleixner
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