linux-kernel - Re: [BUG] 6.16-rc7: lockdep failure with max77620-gpio/max77686-rtc

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Message-ID: <b91dd3c5-c24e-43d1-8d06-8ec4d01f2762@sirena.org.uk>
Date: Thu, 31 Jul 2025 18:03:43 +0100
From: Mark Brown <broonie@...nel.org>
To: "Russell King (Oracle)" <linux@...linux.org.uk>
Cc: Krzysztof Kozlowski <krzk@...nel.org>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	Alexandre Belloni <alexandre.belloni@...tlin.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Bartosz Golaszewski <brgl@...ev.pl>, linux-gpio@...r.kernel.org,
	linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org,
	Thierry Reding <treding@...dia.com>
Subject: Re: [BUG] 6.16-rc7: lockdep failure with max77620-gpio/max77686-rtc

On Thu, Jul 31, 2025 at 05:28:39PM +0100, Russell King (Oracle) wrote:
> On Thu, Jul 31, 2025 at 05:16:13PM +0100, Mark Brown wrote:

> > Yeah, and that's all internals which we're not super encouraged to peer
> > at.  There should be something that'll give us a nesting level
> > somewhere...  

> > Lockdep's handling of nesting is generally fun.

> As I said, I'm just going to disable lockdep to shut up the warning and
> not pursue any further time on this. If someone else cares about it
> (which I doubt) they can try to come up with a solution. I suspect
> nested regmap-irq is extremely rare.

I'm pretty sure it's extremely rare, and I'll have to construct a
virtual setup to actually test.  After poking at it some more I think
we're actually going to need an explicit lock_class_key for each
regmap-irq rather than relying on the default lockdep one.  I'll try to
send out a patch for that today or tomorrow but likely not really tested
- if you could find time to give it a spin on the affected system that'd
be good, but if not no worries.  Thanks for the report and analysis.

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