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From: Valentin Schneider <valentin.schneider@arm.com>
To: Guenter Roeck <linux@roeck-us.net>,
	Alexey Kardashevskiy <aik@ozlabs.ru>,
	Frederic Weisbecker <frederic@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	x86@kernel.org
Subject: Re: [tip: sched/core] sched/core: Initialize the idle task with preemption disabled
Date: Wed, 07 Jul 2021 18:31:55 +0100	[thread overview]
Message-ID: <875yxm6nec.mognet@arm.com> (raw)
In-Reply-To: <c9bd8db3-60ae-1dbe-aa2f-f2fe3d5fe2d9@roeck-us.net>

On 07/07/21 09:35, Guenter Roeck wrote:
> I think I have it. pseries_defconfig, and pseries emulation,
> started with "-smp 2" and qemu-system-ppc64:
>
> [    0.731644][    T1] smp: Bringing up secondary CPUs ...^M
> [    0.750546][    T0] BUG: scheduling while atomic: swapper/1/0/0x00000000^M
> [    0.752119][    T0] no locks held by swapper/1/0.^M
> [    0.752309][    T0] Modules linked in:^M
> [    0.752684][    T0] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.13.0-11855-g77d34a4683b0 #1^M
> [    0.753197][    T0] Call Trace:^M
> [    0.753334][    T0] [c000000008737b20] [c0000000009f9b18] .dump_stack_lvl+0xa4/0x100 (unreliable)^M
> [    0.754224][    T0] [c000000008737bb0] [c000000000190ed0] .__schedule_bug+0xa0/0xe0^M
> [    0.754459][    T0] [c000000008737c30] [c000000001182518] .__schedule+0xc08/0xd90^M
> [    0.754738][    T0] [c000000008737d20] [c000000001182b8c] .schedule_idle+0x2c/0x60^M
> [    0.754945][    T0] [c000000008737d90] [c0000000001a48ec] .do_idle+0x29c/0x3c0^M
> [    0.755145][    T0] [c000000008737e60] [c0000000001a4df0] .cpu_startup_entry+0x30/0x40^M
> [    0.755403][    T0] [c000000008737ee0] [c00000000005ef10] .start_secondary+0x2c0/0x300^M
> [    0.755621][    T0] [c000000008737f90] [c00000000000d254] start_secondary_prolog+0x10/0x14^M
> [    0.764164][    T1] smp: Brought up 1 node, 2 CPUs^M
>
> Guenter

Hmph, I was about to say I couldn't get that, but after cycling between
different PREEMPT options I finally triggered it, so thanks for that!

Same sha1 as yours, invocation is:

  qemu-system-ppc64 vmlinux -smp 2 -nographic -m 1024 -machine pseries,usb=off

with pseries_defconfig + CONFIG_DEBUG_ATOMIC_SLEEP + CONFIG_PREEMPT_VOLUNTARY

Now to dig!

  reply	other threads:[~2021-07-07 17:32 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-12  9:46 [PATCH] sched: Initialize the idle task with preemption disabled Valentin Schneider
2021-05-12 11:15 ` [tip: sched/core] sched/core: " tip-bot2 for Valentin Schneider
2021-07-06 19:44   ` Guenter Roeck
2021-07-06 23:55     ` Valentin Schneider
2021-07-07  4:06       ` Guenter Roeck
2021-07-07 12:03       ` Frederic Weisbecker
2021-07-07 12:11         ` Valentin Schneider
2021-07-07 14:14           ` Guenter Roeck
2021-07-07 14:35             ` Alexey Kardashevskiy
2021-07-07 14:57               ` Valentin Schneider
2021-07-07 15:31                 ` Guenter Roeck
2021-07-07 16:35                 ` Guenter Roeck
2021-07-07 17:31                   ` Valentin Schneider [this message]
2021-07-08  1:50                     ` Alexey Kardashevskiy

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