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From: Thomas Gleixner <tglx@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Hyunwoo Kim <imv4bel@gmail.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Anna-Maria Behnsen <anna-maria@linutronix.de>,
	Kees Cook <kees@kernel.org>,
	Christian Brauner <brauner@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	John Stultz <jstultz@google.com>, Ingo Molnar <mingo@kernel.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH v2] posix-cpu-timers: Dequeue per-thread timers before exchange_tids()
Date: Tue, 01 Sep 2026 16:50:39 +0200	[thread overview]
Message-ID: <87qzjdauv4.ffs@fw13> (raw)
In-Reply-To: <apXGzcA9BmrbrQZv@redhat.com>

On Mon, Aug 31 2026 at 20:24, Oleg Nesterov wrote:
> On 08/31, Thomas Gleixner wrote:
>>
>> On Wed, Aug 26 2026 at 14:55, Oleg Nesterov wrote:
>> > Can we move posix_cpu_timers_exit() or the whole CONFIG_POSIX_TIMERS
>> > sequence in begin_new_exec() up, right after de_thread() before the
>> > "if (retval)" check?
>>
>> Yes, but that does not buy us anything.
>
> I didn't mean this makes sense, I just tried to understand the Hyunwoo's
> fix, in particular the placement of additional posix_cpu_timers_exit().

Fair enough. But as I was staring at it some more, I thought more about
it. Yes, we can do:

     ret = de_thread()
     if (ret)
     	goto out;

     mop_up_posix_timers();

de_thread() only returns failure _before_ the TID swap, so that's safe
and spares sprinkling this extra invocation into de_thread().

What a mess.



  reply	other threads:[~2026-09-01 14:50 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-26 11:41 [PATCH v2] posix-cpu-timers: Dequeue per-thread timers before exchange_tids() Hyunwoo Kim
2026-08-26 12:55 ` Oleg Nesterov
2026-08-27 13:13   ` Hyunwoo Kim
2026-08-31 16:20   ` Thomas Gleixner
2026-08-31 18:24     ` Oleg Nesterov
2026-09-01 14:50       ` Thomas Gleixner [this message]
2026-09-01 15:11         ` Thomas Gleixner
2026-08-31 11:56 ` Thomas Gleixner
2026-08-31 16:19   ` Thomas Gleixner

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