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From: Thomas Gleixner <tglx@linutronix.de>
To: Guenter Roeck <linux@roeck-us.net>,
	Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-s390@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>
Subject: Re: Linux 5.14
Date: Tue, 31 Aug 2021 01:57:03 +0200	[thread overview]
Message-ID: <8735qqfpv4.ffs@tglx> (raw)
In-Reply-To: <87wno2fzbq.ffs@tglx>

On Mon, Aug 30 2021 at 22:32, Thomas Gleixner wrote:

> On Mon, Aug 30 2021 at 13:12, Guenter Roeck wrote:
>> On Sun, Aug 29, 2021 at 03:19:23PM -0700, Linus Torvalds wrote:
>> So far so good, but there is a brand new runtime warning, seen when booting
>> s390 images.
>>
>> [    3.218816] ------------[ cut here ]------------
>> [    3.219010] WARNING: CPU: 1 PID: 0 at kernel/sched/core.c:5779 sched_core_cpu_starting+0x172/0x180
>> [    3.222992]  [<0000000000186e86>] sched_core_cpu_starting+0x176/0x180
>> [    3.223114] ([<0000000000186dc4>] sched_core_cpu_starting+0xb4/0x180)
>> [    3.223182]  [<00000000001963e4>] sched_cpu_starting+0x2c/0x68
>> [    3.223243]  [<000000000014f288>] cpuhp_invoke_callback+0x318/0x970
>> [    3.223304]  [<000000000014f970>] cpuhp_invoke_callback_range+0x90/0x108
>> [    3.223364]  [<000000000015123c>] notify_cpu_starting+0x84/0xa8
>> [    3.223426]  [<0000000000117bca>] smp_init_secondary+0x72/0xf0
>> [    3.223492]  [<0000000000117846>] smp_start_secondary+0x86/0x90
>>
>> Commit 3c474b3239f12 ("sched: Fix Core-wide rq->lock for uninitialized
>> CPUs") sems to be the culprit. Indeed, the warning is gone after reverting
>> this commit.
>
> The warning is gone, but the underlying S390 problem persists:
>
> S390 invokes notify_cpu_starting() _before_ updating the topology masks.

And interestingly enough that very commit was tested on S390:

  https://lore.kernel.org/r/yt9dy28o8q0o.fsf@linux.ibm.com

Thanks,

        tglx

      reply	other threads:[~2021-08-30 23:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-29 22:19 Linus Torvalds
2021-08-30  9:11 ` Sudip Mukherjee
2021-08-30 15:17   ` Linus Torvalds
2021-09-12 19:29     ` Sudip Mukherjee
2021-08-30  9:39 ` Andy Shevchenko
2021-08-30 11:28   ` Andy Shevchenko
2021-08-30 20:12 ` Guenter Roeck
2021-08-30 20:15   ` Linus Torvalds
2021-08-30 21:28     ` Peter Zijlstra
2021-08-31 11:04       ` Heiko Carstens
2021-08-30 20:32   ` Thomas Gleixner
2021-08-30 23:57     ` Thomas Gleixner [this message]

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