linux-kernel - Re: [PATCH 2/5] of: dynamic: Refactor action prints to not use "%pOF" inside devtree

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Message-ID: <ZMnNcJ2KW1qUZUA5@smile.fi.intel.com>
Date:   Wed, 2 Aug 2023 06:28:48 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Rob Herring <robh@...nel.org>
Cc:     Frank Rowand <frowand.list@...il.com>,
        "Enrico Weigelt, metux IT consult" <info@...ux.net>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Petr Mladek <pmladek@...e.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] of: dynamic: Refactor action prints to not use
 "%pOF" inside devtree_lock

On Tue, Aug 01, 2023 at 03:54:45PM -0600, Rob Herring wrote:
> While originally it was fine to format strings using "%pOF" while
> holding devtree_lock, this now causes a deadlock.  Lockdep reports:
> 
>     of_get_parent from of_fwnode_get_parent+0x18/0x24
>     ^^^^^^^^^^^^^
>     of_fwnode_get_parent from fwnode_count_parents+0xc/0x28
>     fwnode_count_parents from fwnode_full_name_string+0x18/0xac
>     fwnode_full_name_string from device_node_string+0x1a0/0x404
>     device_node_string from pointer+0x3c0/0x534
>     pointer from vsnprintf+0x248/0x36c
>     vsnprintf from vprintk_store+0x130/0x3b4
> 
> To fix this, move the printing in __of_changeset_entry_apply() outside the
> lock. As there's already similar printing of the same changeset actions,
> refactor all of them to use a common action print function. This has the
> side benefit of getting rid of some ifdefs.

...

> v3:
>  - Add missing 'static' reported by 0-day

It reported two issues (at least what I see).

...

> +	if (pr_debug("notify "))

This is weird. How did you compile it?

> +		of_changeset_action_print(action, pr->dn, pr->prop ? pr->prop->name : NULL);

-- 
With Best Regards,
Andy Shevchenko