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From: Finn Thain <fthain@linux-m68k.org>
To: Michael Schmitz <schmitzmic@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>,
	 Geert Uytterhoeven <geert@linux-m68k.org>,
	linux-m68k@lists.linux-m68k.org
Subject: Re: spinlock recursion when running q800 emulation in qemu
Date: Fri, 8 Mar 2024 20:15:11 +1100 (AEDT)	[thread overview]
Message-ID: <cb98b504-0669-eb91-4da0-8ee7bb7663ba@linux-m68k.org> (raw)
In-Reply-To: <6eeccba7-6877-dd3c-2a67-94ea448bead6@gmail.com>

On Fri, 8 Mar 2024, Michael Schmitz wrote:

> 
> > IMHO, Gueunter would do better to instrument the spinlock tests on the 
> > assumption that the locking in arch/m68k really is correct.
> 
> I've come to agree - maybe logging any run queue locks taken by the init 
> task with IRQs enabled might help?
> 

If I understood how the spinlock test algorithm worked, I'd be adding 
sanity checks to it to test the assumptions underlying that algorithm.

I would not be surprised if it uses logic that sees irqs_disabled() and 
then assumes that all hard irqs are disabled, or something similar.

I don't think I'd be adding printk() because the BUG is intermittent and 
printk() messes with timing.

  reply	other threads:[~2024-03-08  9:14 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-04 17:58 spinlock recursion when running q800 emulation in qemu Guenter Roeck
2024-03-05  0:33 ` Finn Thain
2024-03-05  0:48   ` Michael Schmitz
     [not found]   ` <fcb506f2-523d-4efc-ae3d-fe3c79c6f09e@gmail.com>
2024-03-05  0:58     ` Guenter Roeck
2024-03-05  1:06       ` Michael Schmitz
2024-03-06  7:14 ` Michael Schmitz
2024-03-06  8:30   ` Brad Boyer
2024-03-06 23:13     ` Finn Thain
2024-03-06 23:46       ` Guenter Roeck
2024-03-07 23:35         ` Finn Thain
2024-03-06 23:42     ` Michael Schmitz
2024-03-06 23:52   ` Finn Thain
2024-03-08  0:20     ` Michael Schmitz
2024-03-08  0:56       ` Finn Thain
2024-03-08  8:06         ` Michael Schmitz
2024-03-08  9:15           ` Finn Thain [this message]
2024-03-08  9:33             ` Finn Thain
2024-03-08 20:14               ` Michael Schmitz
2024-03-09  5:02                 ` Finn Thain
2024-03-09 20:56                   ` Michael Schmitz
2024-03-09 22:18                     ` Finn Thain
2024-03-11  7:06                       ` Michael Schmitz
2024-03-11  8:35                         ` Finn Thain
2024-03-12  0:51                           ` Michael Schmitz
2024-03-12  7:59                             ` Geert Uytterhoeven
2024-03-12 20:14                               ` Michael Schmitz
2024-03-13  0:16                               ` Michael Schmitz
2024-03-13  4:39                                 ` Preemption (was: Re: spinlock recursion when running q800 emulation in qemu) Michael Schmitz
2024-03-13  4:40                                 ` spinlock recursion when running q800 emulation in qemu Finn Thain
2024-03-13  5:34                                   ` Michael Schmitz
2024-03-14  0:59                                   ` Michael Schmitz
2024-03-15  4:32                                     ` Michael Schmitz
2024-03-15  7:24                                       ` Finn Thain
2024-03-18  6:24                                         ` Michael Schmitz
2024-03-18  9:31                                           ` Finn Thain
2024-03-20  1:00                                             ` Michael Schmitz

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