From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>, Rik van Riel <riel@redhat.com>,
Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/6] stop_machine: cleanups, fix, remove lglock
Date: Thu, 30 Jul 2015 19:34:16 +0200 [thread overview]
Message-ID: <20150730173416.GP25159@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150721192219.GA31150@redhat.com>
On Tue, Jul 21, 2015 at 09:22:19PM +0200, Oleg Nesterov wrote:
> Hello,
>
> Let me resend this. The only change in v2 is that I rediffed this
> series against v4.2-rc3.
>
> 5/6 patch fixes the bug, I think. Say, stop_one_cpu(X) can race with
> _cpu_down(X)->stop_machine() so that the kernel will crash if this
> CPU X becomes online again. The window after cpu_stopper_thread()
> returns and before smpboot_thread() calls ->park() is tiny, but still
> this is possible afaics. But see the changelog in 6/6, I think we
> should turn this cpu_stop_signal_done() into BUG() later.
These I've queued (from v1 I think, nothing really changed there).
> 6/6 removes lglock from kernel/stop_machine.c.
>
> Peter, Rik, what do you think ?
This one I've got some 'problems' with, but let me reply there.
prev parent reply other threads:[~2015-07-30 17:34 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-21 19:22 [PATCH v2 0/6] stop_machine: cleanups, fix, remove lglock Oleg Nesterov
2015-07-21 19:22 ` [PATCH v2 1/6] stop_machine: move cpu_stopper_task and stop_cpus_work into struct cpu_stopper Oleg Nesterov
2015-07-21 19:22 ` [PATCH v2 2/6] stop_machine: don't do for_each_cpu() twice in queue_stop_cpus_work() Oleg Nesterov
2015-07-21 19:22 ` [PATCH v2 3/6] stop_machine: unexport __stop_machine() Oleg Nesterov
2015-07-21 19:22 ` [PATCH v2 4/6] stop_machine: use cpu_stop_fn_t where possible Oleg Nesterov
2015-07-21 19:22 ` [PATCH v2 5/6] stop_machine: cpu_stop_park() should remove cpu_stop_work's from list Oleg Nesterov
2015-07-21 19:22 ` [PATCH v2 6/6] stop_machine: kill stop_cpus_lock and lg_double_lock/unlock() Oleg Nesterov
2015-07-30 21:55 ` Peter Zijlstra
2015-07-31 11:12 ` Peter Zijlstra
2015-07-31 14:17 ` Peter Zijlstra
2015-08-03 14:58 ` Oleg Nesterov
2015-08-01 10:57 ` Oleg Nesterov
2015-08-01 22:36 ` Peter Zijlstra
2015-08-03 14:58 ` Oleg Nesterov
2015-07-30 17:34 ` Peter Zijlstra [this message]
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