From: Rabin Vincent <rabin@rab.in>
To: Ingo Molnar <mingo@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@us.ibm.com>
Subject: Re: qemu:arm test failure due to commit 8053871d0f7f (smp: Fix smp_call_function_single_async() locking)
Date: Mon, 20 Apr 2015 17:41:48 +0200 [thread overview]
Message-ID: <20150420154148.GA18104@debian> (raw)
In-Reply-To: <20150419180140.GA8934@gmail.com>
On Sun, Apr 19, 2015 at 08:01:40PM +0200, Ingo Molnar wrote:
> That's all fine and good, but why is an IPI sent to a non-existent
> CPU? It's not like we don't know which CPU is up and down.
The perf events code is trying to call smp_call_function_single() on the
non-existent CPU in perf_event_exit_cpu_context() while handling the
CPU_UP_CANCELED notification. perf_cpu_notify() handles CPU_UP_CANCELED
and CPU_DOWN_PREPARE in the same way.
(cpu_up() is tried for the non-existing CPUs because in this case what
is specified in the device tree does not match reality.)
next prev parent reply other threads:[~2015-04-20 15:42 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-18 23:23 qemu:arm test failure due to commit 8053871d0f7f (smp: Fix smp_call_function_single_async() locking) Guenter Roeck
2015-04-18 23:40 ` Guenter Roeck
2015-04-19 0:04 ` Linus Torvalds
2015-04-19 0:36 ` Guenter Roeck
2015-04-19 1:56 ` Guenter Roeck
2015-04-19 3:39 ` Rabin Vincent
2015-04-19 4:03 ` Guenter Roeck
[not found] ` <CA+55aFw4FSja+VBuCYJ7wLXKVRQZ7w6vOUaUJ4B=FXyBmNkrUg@mail.gmail.com>
2015-04-19 8:56 ` Linus Torvalds
2015-04-19 9:31 ` Ingo Molnar
2015-04-19 14:08 ` Guenter Roeck
2015-04-19 18:01 ` Ingo Molnar
2015-04-19 20:34 ` Linus Torvalds
2015-04-20 5:39 ` Ingo Molnar
2015-04-20 12:17 ` Paul E. McKenney
2015-04-20 15:53 ` Linus Torvalds
2015-04-20 15:41 ` Rabin Vincent [this message]
2015-04-20 10:46 ` Geert Uytterhoeven
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