linux-kernel - Re: [PATCH RESEND] Do not mark ACPI devices as irq safe

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Message-ID: <CAHp75VdbRexEx90ybaFsiPhg8O0CzvpkWT1ER31GnP-y8a1e+w@mail.gmail.com>
Date: Fri, 9 Aug 2024 14:03:27 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Andi Shyti <andi.shyti@...nel.org>
Cc: Breno Leitao <leitao@...ian.org>, Laxman Dewangan <ldewangan@...dia.com>, 
	Dmitry Osipenko <digetx@...il.com>, Thierry Reding <thierry.reding@...il.com>, 
	Jonathan Hunter <jonathanh@...dia.com>, leit@...a.com, 
	Michael van der Westhuizen <rmikey@...a.com>, 
	"open list:I2C SUBSYSTEM HOST DRIVERS" <linux-i2c@...r.kernel.org>, 
	"open list:TEGRA ARCHITECTURE SUPPORT" <linux-tegra@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND] Do not mark ACPI devices as irq safe

On Fri, Aug 9, 2024 at 2:57 AM Andi Shyti <andi.shyti@...nel.org> wrote:
> On Thu, Aug 08, 2024 at 05:14:46AM GMT, Breno Leitao wrote:
> > On ACPI machines, the tegra i2c module encounters an issue due to a
> > mutex being called inside a spinlock. This leads to the following bug:

First of all, ...

> >       BUG: sleeping function called from invalid context at kernel/locking/mutex.c:585
> >       in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1282, name: kssif0010
> >       preempt_count: 0, expected: 0
> >       RCU nest depth: 0, expected: 0
> >       irq event stamp: 0
> >
> >       Call trace:
> >       dump_backtrace+0xf0/0x140
> >       show_stack (./arch/x86/include/asm/current.h:49
> >                    arch/x86/kernel/dumpstack.c:312)
> >       dump_stack_lvl (lib/dump_stack.c:89 lib/dump_stack.c:115)
> >       dump_stack (lib/earlycpio.c:61)
> >       __might_resched (./arch/x86/include/asm/current.h:49
> >                        kernel/sched/core.c:10297)
> >       __might_sleep (./include/linux/lockdep.h:231
> >                        kernel/sched/core.c:10236)
> >       __mutex_lock_common+0x5c/0x2190
> >       mutex_lock_nested (kernel/locking/mutex.c:751)
> >       acpi_subsys_runtime_resume+0xb8/0x160
> >       __rpm_callback+0x1cc/0x4b0
> >       rpm_resume+0xa60/0x1078
> >       __pm_runtime_resume+0xbc/0x130
> >       tegra_i2c_xfer+0x74/0x398
> >       __i2c_transfer (./include/trace/events/i2c.h:122 drivers/i2c/i2c-core-base.c:2258)

...read Submitting Patches and make the above to be ~5-6 significant
(useful) lines only.

> > The problem arises because during __pm_runtime_resume(), the spinlock
> > &dev->power.lock is acquired before rpm_resume() is called. Later,
> > rpm_resume() invokes acpi_subsys_runtime_resume(), which relies on
> > mutexes, triggering the error.
> >
> > To address this issue, devices on ACPI are now marked as not IRQ-safe,
> > considering the dependency of acpi_subsys_runtime_resume() on mutexes.

This is a step in the right direction, but somewhere in the replies
here I would like to hear about roadmap to get rid of the
pm_runtime_irq_safe() in all Tegra related code.

...

> >        * VI I2C device shouldn't be marked as IRQ-safe because VI I2C won't
> >        * be used for atomic transfers.
> >        */

Does the comment need an expansion?

> > -     if (!IS_VI(i2c_dev))
> > +     if (!IS_VI(i2c_dev) && !ACPI_HANDLE(i2c_dev->dev))
>
> looks good to me, can I have an ack from Andy here?

I prefer to see something like
is_acpi_node() / is_acpi_device_node() / is_acpi_data_node() /
has_acpi_companion()
instead depending on the actual ACPI representation of the device.

Otherwise no objections.
Please, Cc me (andy@...nel.org) for the next version.

-- 
With Best Regards,
Andy Shevchenko